the pennsylvania state university soil test calibration...
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The Pennsylvania State UniversityThe Graduate School
Department of Agronomy
Soil Test Calibration Studies for Turfgrasses
A Thesis inAgronomy
byThomas Reams Turner
Submitted in Partial Fulfillmentof the Requirements
for the Degree of
Doctor of PhilosophyMay' 1980
The signatories below indicate that they have readand approved the thesis of Thomas Reams Turner.
Dat~ of Signature:. Signatories:
Donald V. Waddington, Professor ofSoil Science, Chairman of Committee,Thesis Advisor
James L. Starling,ment of Agronomy
Duich, Professor ofScience
Thomas L. Watschke, AssociateProfessor of Turfgrass Science
Cyril B. Smith, Professor ofPlant Nutrition
Jo<t'K:Hall, Associate Professorof Soil Chemistry
ABSTRACT
Soil testing is the primary means of determining the
phosphorus, potassium, and limestone requirements for turf-
grass establishment and maintenance. For reliable soil test
recommendations, soil test calibration studies must be con-
ducted; however, no extensive calibration studies have beeni
conducted for turfgrasses. These studies were thus conducted
to relate turfgrass response during establishment from seed,
establishment from sod, and maintenance to different levels
of applied P, K, and limestone on soils with different
initial levels of fertility.
Thirteen tests were used to evaluate turfgrass
establishment response from seed to seedbed P, K, and lime-
stone applications. Tests included seedings of a perennial
ryegrass - Kentucky bluegrass and a creeping red fescue-
Kentucky bluegrass mixture,. as well as monocultures of
perennial ryegrass, chewings fescue, and Kentucky bluegrass.
Initial soil fertility values ranged from 5.6 to 6.5 pH, 6
to 76 ppm P, 0.08 to 0.20 meq K/lOOg, 4.1 to 6.1 meq Ca/100g, .
0.8 to 2.2% K saturation, and 41.7 to 64.5% Ca saturation.
Limestone and K applications to these soils decreased the
rate of establishment and had no important beneficial effects
during the first year of establishment. On soils with less
than 30 ppm P, most rapid and satisfactory establishment
occurred when soil P was increased to 40 to 70 ppm from seed-
bed P applications of 1.3 to 4.0 kg/a. Higher P rates gave
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little additional benefit. On soil with an initial level of78 ppm P, no increase in rate of establishment was obtainedwith P applications. Also, P raked into the surface 1.2 cmresulted in similar response as higher·P rates incorporatedto a depth of 11 cm.
Two tests were used to evaluate establishmentresponse from Kentucky bluegrass sod. Initial soil fertilityvalues ranged from 5.5 to 6.5 pH, 15 to 17 ppm P, 0.11 to0.12 meq K/lOOg, 3.8 to 6.1 meq Ca/lOOg, 1.1 to 1.3% K satura-tion, and 38.5 to 65.6% Ca saturation. No important effectof P, K, or limestone applications to the sodbed wasmeasured for clipping yield, turfgrass quality, or sod root-ing in the first year of establishment.
Four tests were used to evaluate Kentucky bluegrass,perennial ryegrass, and creeping red fescue response tomaintenance applications of N, P, K, and limestone. Initialsoil fertility values ranged from 5.1 to 6.5 pH, 6 to 32 ppmP, 0.12 to 0.26 meq K/lOOg, 2.8 to 4.5 meq Ca/lOOg, 1.2 to3.0% K saturation, and 32.8 to 60.8% Ca saturation.Virtually no beneficial Or detrimental response to limestone,P, or K applications was· obtained during the duration ofthe study for clipping yields, turfgrass quality, diseaseincidence, or weed encroachment.
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TABLE OF CONTENTS
ABSTRACT. • • • . . . . . . . . . . . . ..LIST OF TABLES •• . . . . .. . . . . . . . .LIST OF FIGURES
ACKNOWLEDGEMENTS. • •
INTRODUCTION. • • • • · t ·GENERAL METHODS AND MATERIALS •
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CHAPTER 1. SOIL TEST CALIBRATION STUDIES FOR THEESTABLISHMENT OF TURFGRASS FROM SEEDAND SOD • • • • •• • • • •••• 26
TEST SITE A ..•••Methods and Materials •Results and Discussion.
Soil Fertility Values •Elemental Tissue Analysis • . • . • • • .Clipping Yields • • • • • •Ground Cover, Turfgrass Quality,
Crabgrass Encroachment, andSod Strength.. •••• .• ·
Conclusions • • • • • • •
TEST SITE B • • • • • • • • • •• • • . •Methods and Materials ••••••••Results and Discussion. • • • • • • ·
Soil Fertility Values •• ••••••Elemental Tissue Analysis • • • • • •Clipping Yields • • • • • • • • .Ground Cover, Turfgrass Quality, and
Sod Strength. • . • •Conclusions • • • • • • • • • • • • • • •
TEST SITE C • • • • • • • •Methods and Materials •Results and Discussion.Conclusions • • • • • •
TEST SITE D • • • • • • • • • • • • • • •Methods and Materials ••.••.••••Results and Discussion.. •••• • • • •
Elemental Tissue Analysis • . • • • • • •Clipping Yields, Sod Rooting, and
Turfgrass Quality • .Conclusions. • • . • • • • • • •
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103104
TABLE OF CONTENTS (Continued)
CHAPTER 2.· SQIL TEST ·CALIBRATION STUDIES FOR TURF-' .. J ;,GRASS MAINTENANCE. • • • • • • • •
TEST SITE E. • • • • • .• •••••••Methods and Materials ••••.Results and Discussion • •••
Soil Fertility Values. • ••Elemental Tissue Analysis •••Clipping Yields ..•••• ·Turfgrass Quality, Disease Incidence,
and Dandelion Encroachment •Conclusions. • • • • .
· . . .· .
TEST SITE F. • • • • • • • • .•• •• • •Methods and Materials ••••••• • • • •• •Results and Discussion •••••.••
Soil Fertility Values. • • • • • •Elemental Tissue Analysis ••..•• •Clipping Yields. • . • • • • • · • • • • •Turfgrass Quality, Red Thread
Incidence, and CrabgrassEncroachment •
Conclusions. • • . • • . • •· . . .· . . .
TEST SITE G. . • • • . . • • . • . • • • • • •Methods and Materials ••Results and Discussion .
Soil Fertility Values ••Elemental Tissue Analysis ••Clipping Yieldi. • • • • • • •Turfgrass Quality, L~af Spot
Incidence, and CrabgrassEncroachment • •
Conclusions. • • • . • • • • • • • • •
TEST SITE H. . • . • ~ • •Methods and Materials ••Results and Discussion • • • • . . • . • • • •
Soil Fertility Values.Elemental Tissue Analysis ••Clipping Yields •••••.•• • •Turfgrass Quality. • •
Conclusions. . • • • • • •
· . . .
GENERAL SUMMARY AND CONCLUSIONS •• . . . . . . . .LITERATURE CITED • . . . . . . . . . . . .APPENDIX.
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Table1
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LIST OF TABLES
The initial soil fertility values forSite A • • • • • • •• •••.• . . . ..Phosphorus, potassium, and limestone treat-ments and their coded values for Site A. • •Soil fertility value response equations tolimestone, P, and K applications (Site Aibluegrass-perennial ryegrass studYi 3 May1978) . . . . .Soil fertility value response equations tolimestone, P, and K applications (Site Aibluegrass-perennial ryegrass studYi 30October 1978) •. ~ •..••..•••Soil fertility value response equations tolimestone~ P, and K applications (Site Aibluegrass-red fescue studYi 3 May 1978) .• . . . .Soil fertility value response equationsto limestone, P, and K applications(Site Ai bluegrass-red fescue study,30 October 1978) . • • . • . • • • • • • • •
7 Elemental tissue analysis response equationsto limestone, P, and K applications (Site Aibluegrass-perennial ryegrass studYi 31October 1977) •••••••••••••• • •
8 Elemental tissue response equations to lime-stone, P, and K applications (Site Ai blue-grass-perennial ryegrass studYi 14 June 1978).
9 Elemental tissue analysis response equationsto limestone, P, and K applications (Site Ai~luegrass-red fescue studYi 31 October 1977)
10 Elemental tissue analysis responseequations to limestone, P, and K appli-cations (Site Ai bluegrass-red fescuescudy r 14 June 1978) • • • .• •.•
11 Turfgrass clipping yield responseequations to limestone, P, and K appli-cations (Site Ai bluegrass-perennialryegrass seeded 13 September 1977) • • • . . . . .
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Table12
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14
15
Turfgrass clipping yield responseequations to limestone, P, and Kapplications (Site A; bluegrass-redfescue seeded 13 September 1977) . . . .Ground cover, quality, crabgrass encroachment,and sod strength response equations to lime-stone, P, and K applications (Site A;bluegrass-perennial ryegrass seeded13 September 1977). • • • • . . . • • • . •• •
Ground cover, .quality, crabgrass encroachment,and sod strength response equations to lime-stone, P,and K applications (Site A;bluegrass-red fescue seeded 13 September1977). . . . . . . . . . . . e. • • • • • • • • •
Initial soil fertility values forSite B .'. • • • •. •• ••• • • . . . . . .
16 Phosphorus, potassium, and limestonetreatments and their coded values forSite B • • • • • • • • • • • • • • • • •
17 Soil fertility value response equat~onsto limestone, P, and K applications(Site B; 29 April 1978). . • . • . •
18 Soil fertility response equations tolimestone, P, and K applications(Site B; 25 October 1978) ....••
19 Elemental tissue analysis responseequations to lim~stone, P, and Kapplications (Site B; bluegrass study;26 May 19 78) .••.••••• • • • • •
20 Elemental tissue analysis responseequations to limestone, P, and Kapplications (Site B; chewingsfescue study; 26 May 1978) . . • . • • • . • . •
21 Elemental tissue analysis responseequations to limestone, P, and Kapplications (Site B; perennial rye-grass study; 2 June 1978) •.•..•••• • • •
22 Turfgrass clipping yield responseequations to limestone, P, and Kapplications (Site B; bluegrassstudy) • . • • . • • • • • • • • • • • • • • • •
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Table23
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Turfgrass clipping yield responseequations to limestone, P, and Kapplications (Site Bi chewingsfescue study) • • • • • •• • • • • • • •• • •Turfgrass clipping yield responseequations to limestone, P, and Kapplications (Site Bi perennial rye-grass study) ••.•••••••••• . . . . .Ground cover, quality, and sod strengthresponse equations to limestone, P, andK applications (Site B; bluegrassseeded 29 September 1977) • • • • • • • • • • •Ground cover, quality, and sod strengthresponse equations to limestone, P, andK applications (Site Bi chewings fescueseeded 29 September 1977) • • •• • • • • • • •Ground cover and quality responseequations to limestone, P, and K·applications (Site Bi perennial rye-grass study*) . • . • . • • • •• •••••
28 The initial soil fertility values forSi te C. • • • . . • • • • • • • . · . . . . . .
29 Phosphorus and potassium treatmentsand their coded values for tests Clthrough C4. • • . • • • • • • . . .• . . . .
30 Phosphorus and limestone treatments andtheir coded values for tests C5 throughC8. • • • • • • ~ • • • • • • • • •
31 Soluble salt and relative bluegrass germina-tion response equations to phosphorus andpotassium applications (Site Ci tests Clthrough C4) • • • • • • • • • • • • • • • • • •
32 Percent ground cover response equationsto phosphorus and limestone applications(Site Ci tests C5 through C8i 28 September1978) . . '.. . . . . . . . . . . . . . . · ·
33 lIlitial soil fertility levels of soil and sodfor Site 0 and Penn State recommendations forsod establishment •• •• • • • • • • • • •
34 Phosphorus, potassium and limestone treatmentsand their coded values for tests 01 and 02. • •
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Table35
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initial soil fertility values forSit.e E. • • • • • • • • • • • . . . ." .Nitrogen, phosphorus, potassium, andlimestone treatments and their codedvalues for Site E • • • • • • • • . • . . . . .Soil fertility value response equationsto limestone, P, andK a:pplications(Site E; 1 Novembe r 1978) ••..•• • . . . .Elemental tissue analysis response equationsto limestone, P, and K applications (Site E;26 May 1978) .••••.. ~ • • • • • . •
39 Turfgrass clipping yield response equations tolimestone, P, and K applications (Site E) •Quality, winter injury, disease incidence,and dandelion encroachment responseequations to limestone, P, and K applica-tions (Site E) ••• ~ • . •• • ••• •
41 Initial soil fertility values for Site F.42 Nitrogen, phosphorus, potassium, and lime-
stone treatments and their coded valuesfor Site F. •.• • .'. :..• '. • • . · • •
43 Soil fertility value response equations toN, P, K, and limestone applications (Site F;9 October 1978) •••..•••••.• • • • • •
44 Elemental tissue analysis responseequations to N, P, K, and limestoneapplications (Site F; 11 May 1978).
45 Clipping yield response equations to N, P,K, and limestone applications (Site F).
46 Turfgrass quality, red thread incidence, andcrabgrass encroachment response equations toN, P, K, and limestone applications (Site F). •
47 Initial soil fertility values for Site G. •48 Nitrogen, phosphorus, potassium, and lime-
stone treatments and their coded values forSite G. • • • • . • • •_•_. • . . . . .
49 Soil fertility value response equations tolimestone, P, and K applications (Site G;30 May 1978). • • • • • • · • • • •
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Table50
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Elemental tissue analysis responseequations to N,P, K, and limestoneapplications (Site Gi 5 June 1978) • .. .Clipping yield response equations to N,P, K, and limestone applications (Site G) ••
Turfgrass quality, Helminthosporium leafspotincidence, and crabgrass encroachmentresponse equations (Site G)•••••••••Initial soil fertility values forst te H . • • .• • . • '. • • • • • • • . . . . . .Nitrogen, phosphorus, potassium, andlimestone treatments and their codedvalues for Site H. • • • • • • • • •
55 Soil fertility value response equationstoN, P, K, and limestone applications(Site Hi 11 May 1978) ••••••••••
56 Elemental tissue analysis response equationsto N, P, K, and limestone applications(Site Hi 5 June 1978). •• • • • . • • • • •
57 Clipping yield response equations to N,' P,K, and limestone applications (Site H). • • • •
58 Turfgrass quality response equations toNt P, K# and limestone applications(Site H) • • • • • • • • • • • • • •
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Figure
LIST OF FIGURES
1 The effect of phosphorus and limestoneapplications on soil pH (Site Ai bluegrass-ryegrass scudy r 3 May 1978) • • • • • • • • •
2 The effect of limestone applications Onsoil pH (Site A; bluegrass-ryegrassstudy; 30 October 1978) ••••••••
3 The effect of phosphorus and limestoneapplications on soil buffer pH (Site Aibluegrass-ryegrass studYi 3 May 1978) •
4 .The effect of phosphorus and limestoneapplications of soil buffer pH (Site A;bluegrass-ryegrass study; 30 October 1978) ••••
The effect of phosphorus application!on available soil phosphorus (Site Aibluegrass-ryegrass studYi 3 May 1978and 30 October 1978) •••.•••••
5
6 The effect of phosphorus and potassiumapplications on exchangeable soilpotassium (Site Ai bluegrass-ryegrassstudy i 3 May 1978). • . •• • . • • •
7 The effect of limestone and potassiumapplications on exchangeable soilpotassium (Site Ai bluegrass-ryegrassstudy; 30 October 1978) . . . • • • • • • • • • •
8 The effect of potassium applications onpercent potassium saturation (Site A; blue-grass-ryegrass s cudy r 3 May 1978) •• • •••
9 The effect of phosphorus applications onpercent potassium saturation (Site Ai b1ue-grass-ryegrass studYi 3 May 1978) • • • • •
10 The effect of limestone and potassiumapplications on percent potassium satura-tion (Site Ai bluegrass-ryegrass study;30 October 1978) .•••.•...••.••
11 The effect of potassium and limestoneapplications on exchangeable soil calcium(Site A; bluegrass-ryegrass study;3 May 1978) •.. • • •• .•••••.
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Figure
12 The effect of limestone applicationson exchangeable soil calcium (Site Aibluegrass-ryegrass studYi 30 October1978) . . . . . . . .. ... ...
13 The effect of potassium and limestoneapplications on percent calcium satura-tion (Site Ai bluegrass-ryegrass studYi3 May 19 78) ~ • • • • . • • • • • • • • • . • • .•
14 The effect of phosphorus applicationson percent calcium saturation (Site Aibluegrass-ryegrass study r 3 May 1978)
15 The effect of potassium and limestoneapplications on percent calciumsaturation (Site Ai bluegrass-ryegrassstudYi 30 October 1978) . • • • • • •
16 The effect of potassium applicationson exchangeable soil magnesium (Site Aibluegrass-ryegrass studYi 3 May 1978) •
17 The effect of phosphorus applicationson exchangeable soil magnesium (Site Aibluegrass-ryegrass studYi 30 October1978) . . . . . . . . . . . . . . . . . . . . ...
18 .The effect of potassium applicationson percent magnesium saturation (Site A;bluegrass-ryegrass study; 3 May 1978)
19 The effect of phosphorus applicationson percent magnesium saturation (Site Aibluegrass-ryegrass study; 30 October1978) . ., . . . . . . . . . . . . . . . . . . ...
20 The effect of phosphorus and limestoneapplications on soil pH (Site A; blue-grass-red fescue study; 3 May 1978) • •
21 The effect of limestone applications onsoil pH (Site A; bluegrass-red fescuestudy; 3 May 19 78). • . . • • • • • • •
22 The effect of phosphorus and limestoneapplications on soil buffer pH (Site A;bluegrass-red fescue study; 3 May 1978)
23 The effect of limestone applications onsoil buffer pH (Site Ai bluegrass-redfescue studYi 30 October 1978) •••••
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Figure
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The effect of phosphorus applicationson available soil phosphorus (Site A;bluegrass-red fescue study; 3 May 1978and 30 October 1978) • • • • • • • • .'. . . . .The effect of potassium applications onexchangeable soil potassium (Site A;bluegrass-red fescue study; 3 May 197'8and 30 October 1978) . • • . • . • • •• • • • •
The effect of potassium applicationson percent potassium saturation (Site A;bluegrass-red fescue study; 3 May 1978and 30 October 1978) • • • • • • • • • •
Th~ effect of limestone applications onexchangeable soil calcium. (Site Ai blue-grass-red fescue study; 3 May 1978 and30 October 1978) • • • . . . • • • .• •
The effect of potassium and phosphorusapplications on exchangeable soilcalcium (Site Ai bluegrass-red fescuei30 October 1978) ••.•..• ,••••
The effect of limestone applications onpercent calcium saturation (Site Aibluegrass-red fescue studYi 3 May 1978).
30 The effect of phosphorus and limestoneapplications on percent calcium satura-tion (Site A; bluegrass-red fescue studYi30 October 1978) • • • • • • . • • . •
31 The effect of potassium and limestoneapplications on exchangeable soil magnesium(Site Ai bluegrass-red fescue study;3 May 1978) •••••••.•• '. • • • • •
32 The effect of potassium and phosphorusapplications on exchangeable soilmagnesium (Site A; bluegrass-red fescuestudy; 30 October 1978). •••• • • • • • •
33 The effect of phosphorus and potassiumapplications on percent magnesium satura-tion (Site A; bluegrass-red fescue studYi3 May 1978). • . • • •• •••.• •••
34 The effect of phosphorus and potassium appli-cations on percent magnesium saturation(Site Ai bluegrass-red fescue study;30 October 1978) • • •• ••.•••••••
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Figure
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35 . The effect of limestone applications onpercent magnesium saturation (Site A;bluegrass-red. fescue study; 3 May 1978and 30 October 1978) • . • • • • .'. •
36 The effect of phosphorus applications ontissue phosphorus (Site A; b1uegrass-rye-grass study; 31 October 1977 and 14 June197"8) •••••••••••• '••••
37 The effect of potassium applications ontissue calcium (Site A; b1uegrass-ryegrassstudy; 31 October 1977 and 14 June 1978) •
38 The effect of potassium and phosphorusapplications on tissue magnesium (Site A;b1uegrass-ryegrass study; 14 June 1978) ••
The effect of phosphorus applications ontissue iron (Site A; b1uegrass-ryegrassstudy; 31 October 1977) •••.•••••
39
40 The effect 'of potassium and phosphorusapplications on tissue iron (Site Ai blue-grass~ryegrass study; 14 June 1978) •••• ,••••
41 The effect of potassium and limestoneapplications on tissue iron (Site A; blue-grass-ryegrass studYi 14 June 1978) ••
The effect of limestone and phosphorusapplications on tissue magnanese (Site A;bluegrass-ryegrass study; 31 October 1977)
The effect of limestone and phosphorusapplications on tissue magnanese (Site A;bluegrass-ryegrass study; 14 June 1978). •
The effect of phosphorus, limestone andpotassium'applications on tissue copper(Site A; bluegrass-ryegrass study;14 June 1978). • • . • . • • . • . • '. .
45 The effect of phosphorus applications ontissue aluminum (Site A; b1uegrass-ryegrassstudy; 31 October 1977). . • • . . .
The effect of potassium applications ontissue sodium (Site A; bluegrass-ryegrassstudy; 31 October 1977). • ••••.•
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Figure
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The effect of limestone and phosphorusapplications on tissue sodium (Site Aibluegrass-ryegrass studYi 14 June 1978).
The effect of phosphorus applications ontissue phosphorus (Site Ai bluegrass-red-fescue studYi 31 October 1977) • • • • • •
The effect of potassium and phosphorusapplications on tissue phosphorus (Site Aibluegrass-red fescue studYi 14 June 1978).
The effect of limestone and potassiumapplications on tissue potassium (Site A;bluegrass-red fescue study; 31 October1977). . . . . . . . . . . . . . . . .
The effect of potassium and limestoneapplications on tissue calcium (Site Aibluegrass-red fescue studYi 31 October1977). . . . . . . . . . . . . . . . .
The effect of potassium and limestoneapplications on tissue calcium (Site Aibluegrass-red fescue studYi 14 June 1978).
The effect of potassium applications ontissue iron (Site Ai bluegrass-red fescuestudy i 31 October 1977). • . • • • • • • • . . .The effect of potassium and limestoneapplications on tissue iron (Site Ai blue-grass-red fescue studYi 14 June 1978).
The effect of limestone and phosphorusapplications on tissue manganese (Site Aibluegrass-red fescue; 31 October 1977) . • •
The effect of limestone and phosphorusapplications on tissue manganese (Site Aibluegrass-red fescue studYi 14 June 1978).
57 The effect of potassium applications on tissuezinc (Site Ai bluegrass-red fescue studYi14 June 1978). • • • • • • • • • • • • • • • ••
58 The effect of phosphorus applications ontissue aluminum (Site Ai bluegrass-red fescuestudy; 31 October 1977). • •••••••••
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Figure59 .The effect o£ potassium and limestone
applications on tissue aluminum (Site A;bluegrass-red fescue study; 14 June 1978).
60 The effect of potassium applications ontissue sodium (Site A; bluegrass-red fescuestudy; 31 October 1978)•••••••••••
61 The effect of phosphorus and potassiumapplicatioI)s on tissue sodium (Site A;bluegrass-red fescue study; 14 June 1978) ••
62 The effect of potassium and phosphorusapplications on clipping yields seven weeksafter seeding (Site A; bluegrass-ryegrassstudy; 31 October 1977).•.••.•••••
63 The effect of limestone and phosphorusapplications on clipping yields seven weeksafter seeding (Site A; bluegrass-ryegrassstudy; 31 October 1977). • . . . . • • •
64 The effect of ,phosphorus applications onclipping yields (Site A; bluegrass-ryegrassstudy; 3 May and 1 June 1978)..••••••
65 The effect of phosphorus applications onclipping yields (Site A; bluegrass-ryegrassstudy; 14 June and 29 June 1978) . . • • . .
66 The effect of limestone and phosphorus appli-cations on clipping yields (Site A; bluegrass-ryegrass study; 4 August 1978) • . • • • . • • •
67 The effect of limestone and phosphorus appli-cations on clipping yields seven weeks afterseeding (Site A; bluegrass-red fescue study;31 October 1977) • . • . . • . • • • • • • •
68 The effect of potassium and phosphorusappli-cations on clipping yields (Site A; bluegrass-red fescue study; 1 June 1978) •...•.•..
69 The effect of potassium and phosphorus appli-cations on clipping yields (Site A; bluegrass-red fescue study; 14 June 1978).....••.•The effect of potassium and phosphorus appli-cations on clipping yields (Site A; bluegrass-red fescue study; 29 June 1978)•••••••••
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Figure Page71 . The effect of limestone applications on
clipping yields (Site Ai bluegrass-redfescue study i 5 September 1978) ••• ' •• 207The effect of phosphorus applications onpercent ground cover (Site Ai bluegrass-ryegrass.studYi 25 October 1977) •••••••• 207
73' The effect of phosphorus and potassiumapplications on crabgrass encroachment(Site Ai bluegrass-ryegrass studYi4 October 1978) •••••••.•. .••.•• . 208
74 The effect of potassium applications onsod strength (Site Ai bluegrass-ryegrasss tudy r 12 October 1978). • • . • . . • • • • •• 208
75 The effect of ~hosphorus applications onpercent ground cover (Site Ai bluegrass-red fescuestudYi 25 October 1977) • • • • • •• 209
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The effect of phosphorus and potassiumapplications on crabgrass encroachment(Site Ai bluegrass-red fescue studYi4 October 1978) •••.••..•••• 209
The effect of phosphorus and limestoneapplications on soil pH (Site Bi29 April1978) . . . . . .. ..... ..' . 210
The effect of phosphorus and limestoneapplications on soil pH (Site Bi 25 October1978) . . . .' . . . • . . . . . 210
The effect of potassium applications onsoil pH (Site Bi 25 October 1978). • 211
The effect of limestone applications onsoil buffer pH (Site Bi 29 April and 25October 1978) •••••••••••. 211
The effect of phosphorus applications onavailable soil phosphorus (Site Bi 29Ap ri 1 19 78). • • • • • • • • • • • • • • 212
82 . The effect of phosphorus and potassiumapplications on available soil phosphorus(Site Bi 25 October 1978) ••••••
83
212
The effect of potassium applications onexchangeable soil potassium (Site Bi 29 Apriland 25 October 1978)'. • • • • • • • • • • • • • 213
xviii
Figure84 The effect of phosphorus and potassium
applications on percent potassiumsatura-tion (SiteB; 29 April 1978) •••••••
85 The effect of limestone and potassium,applications on percent potassium satura~tion (Site B; 25 October 1978) ••••••
86 The effect of limestone applications onexchangeable soil calcium (Site B; 29April and 25 October 1978) •••••• . . . .
87 The effect of limestone applications onpercent calcium saturation (Site B;29 April 1978). • • •• ••.••• • • • •
88 The effect of limestone and potassiumapplications on percent calcium satura-tion (SiteB; 25 October 1978) •..•.•.
89 The effect of potassium and phosphorusapplications on exchangeable soil magnesium(Site B; 25 October 1978) •••••••••••
90 The effect of limestone applications onpercent magnesium saturation (Site B; 25October 1978) • • • .• ••••••
91 The effect of limestone and phosphorusapplications on tissue phosphorus (Site B;bluegrass study; 26 May 1978) • • • • •
92 The effect of limestone and potassiumapplications on tissue potassium (Site B;bluegrass study; 26 May 1978) ••••••
93 The effect of phosphorus applications ontissue potassium (Site B; bluegrass study;26 May 19 78) ••.••••••••••
94 The effect of potassium applications ontissue calcium (Site B; bluegrass study:26 May 1978). • • • • • . • • • • • • • • • • •
95 The effect of limestone applications ontissue manganese (Site B: bluegrass study;26 May 1978). • • • • • • • • . • • • • • •
96 The effect of potassium applications ontissue aluminum (Site B; bluegrass study:2 6 May 19 78). • • • •• • • • • • • • • • •
xix
Page
213
214
214
215
215
216
216
217
217
218
218
219
219
Figure
97Page
The effect of potassium and phosphorusapplications on tissue sodium (Site B;bluegrass study; 26 May 1978) .•••• . . . . . 220
98 The effect of potassium and phosphorusapplications on tissue phosphoru~ (Site Bifescue study; 26 May 1978) • • • • • • • • •.•• .' 220
99
100
101
102
103
The effect of potassium applicationson tissue potassiUm (Site Bi fescues t.udy r 26 May 1978). • • • . • • • • • 221
The effect of potassium and limestoneapplications on tissue calcium (Site Bifescue studYi 26 May 1978) • . • • • 221
The effect of limestone applicationson tissue manganese (Site Bi fescuestudy; 26 May 1978). • • • • • • •'.• 222
The effect of potassium applicationson tissue sodium (Site B; fescue study;26 May 19 78) • . • • • . • • • . • • • • 222
The effect of limestone and phosphorusapplications on tissue sodium (Site Bi
·fescue study; 26 May 1978) • • . • • • 223
104 The effect of limestone and phosphorusapplications on tissue nitrogen (Site B;ryegrass study; 2 June 1978) ~ • . . . . • • •• 223
105
106
107
108
The effect of phosphorus applicationson tissue phosphorus (Site B; ryegrassst.udyr 2 June 1978). • • . • •.• • • • 224
The effect of limestone and potassiumapplications on tissue potassium (Site B;ryegrass study; 2 June 1978) • • • • • 224
The effect of potassium applications ontissue calcium (Site Bi ryegrass study;2 June 1978) • . • • . • • • . . • • • • 225
The effect of potassium applications ontissue magnesium (Site B; ryegrass study;2 June 1978) • . • • • • • • . • • • • • • 225
109 The effect of potassium applications ontissue iron (Site B; ryegrass studYi2 June 1978) ~ • • •• •• • . • 226
xx
Figure
110
Page
The effect of limestone and phosphorusapplications on tissue manganese (Site B;ryegrass study; 2 June 1978) ••••• 226
III The effect of limestone and potassiumapplications on tissue zinc (Site B;ryegrass study; 2 June .1978). • • • • • • ••• 227
112 The effect of potassium applicationson tissue aluminum (Site B; ryegrassstudy; 2 June 1978) . • • • • • .•• • • • • •• 227
113
114
115
116
117
118
119
The effect of potassium applicationson tissue sodium (Site B; ryegrassstudy; 2 June 1978) • • . • • . • • •• . . . . 228
The effect of limestone and phosphorusapplications on clipping yields (Site B;bluegrass study; 26 May 1978) • . . •__ ·228
The effect of phosphorus applicationson clipping yields (Site B; bluegrassstudy; 2 June and 13 June 1978) • . • • 229
The effect of limestone and phosphorusapplications on clipping yields(Site B; bluegrass study; 27 June 1978) 229
The effect of limestone and potassiumapplications on clipping yields (Site B;bluegrass study; 11 July 1978) .••.•• 230
The effect of potassium applications onclipping yields (Site B; bluegrass study;25 July 1978) • • • •. • . • • . 230
The effect of limestone and potassiumapplications on clipping yields (Site B;bluegrass study: 21 August 1978) •.• 231
120 The effect of limestone and potassiumapplicationson clipping yields (Site B:bluegrass study; 20 September 1978) • • • • .• 231
121 The effect of phosphorus applications. onclipping yields (Site B; fescue study:26 May 1978) ...••••••..•••••• 232
122 The effect of potassium applications onclipping yields (Site B: fescue study;27 June 1978) . • • • • • • • . • • • . 232
xxi
Figure Page123 The effect. of limestone and potassium
applications on clipping yields (Site B;.fescue study; 11 July 1978). •.• • • •.•
124 The·effect of'limestone and phosphorusapplications on clipping yields (Site B;ryegrass study; 2 June 1978) • •.• • • •
125 The effect of limestone and phosphorusapplications on clipping yields (Site B;ryegrass study; 13 June 1978) •••.•••
. '. ~ . 233
. . . 233
234
126 The effect of potassium applicationsonclipping yields (Site B;ryegrass study;11 July 1978). • • • . • • • ••.• • .'. 234
127 The effect of limestone and potassiumapplications on clipping yields (Site B;ryegrass study; 25 July 1978).. • • .'!..•
The effect of limestone and potassiumapplications on clipping yields (Site B;ryegrass study; 21 August 1978) ••.••
235128
235
129 The effect of phosphorus and limestomeapplications on clipping yields (Site B;ryegrass study; 20 September 1978) .••••.• 236
130 The effect of phosphorus and potassiumapplications on percent ground cover(Site B; bluegrass study; 2 November 1977) 236
131 The effect of phosphorus and potassiumapplications on percent ground cover(Site B; bluegrass study; 12 April 1978) • • •• 237
132 The effect of phosphorus applications onquality (Site B; blu~grass study; 31 Mayand 27 June 1978 • • • . • • • • • • • • • • •• 237
133 The effect of phosphorus and limestoneapplications on sod strength (Site B;bluegrass study; 11 October 1978). • • . • • •• 238
134 The effect of phosphorus applications onpercent ground cover (Site B; fescue study;2 November 1977 and 12 April 1978) • • • • • 238
135 The effect of phosphorus applications onquality (Site B; fescue study; 31 May 1978). 239
xxii
Figure
136
137
138
139
140
The effect of phosphorus and limestoneapplications on quality (Site Bi fescuestudy; 11 October 1978) ••••••••••
The ,effect of potassium and limestoneapplications on quality (SiteBi fescuestudy; 11 October 1978). • • • • • .•.•
The effect of potassium and limestoneapplications on sod strength (Site B;fescue study; 11 October 1978) ••••
. . . . .
The effect of phosphorus applicationson percent ground cover (Site B; ryegrassstudy; 2 November 1977 and 31 May 1978) ••
The effect of phosphorus applications onquality (Site B; ryegrass study; 27 Juneand 26 July 1978). • • • .• • • ••
141 The effect of potassium applications onsoluble salts (Site C;tests Cl, C3, andC4; 5 September 1978) ••••.•••
142 The effect of potassium applications onsoluble salts (Site C; test C2;5 September 1978)., • • • • • • • • •
143
144
145
146
147
148
The effect of potassium applications onrelative bluegrass germination (Site C;tests Cl I C3 I and C4; 30 August 1978).··.
The effect of potassium applications onrelative bluegrass germination (Site C;test.C2; 30 August 1978) •.•••••
The effect of limestone and phosphorusapplications on percent ground cover(Site C; test C5; 28 September 1978) • . .'. . .The effect of limestone and phosphorusapplications on percent ground cover(Site Ci test C7; 28 September 1978) ••
The effect of limestone applications onpercent ground cover (Site C; test C8;28 September 1978} • . . • • • • • • • •
The effect of phosphorus application onpercent ground cover (Site C; test C6iSeptember 1978). • • • • • • • • • • • •
xxiii
Page
239
240
240
241
241
242
242
243
243
244
244
245
245
Figure
149
150
151
152
153
154
155
156
157
158
159
160
161
The effect of phosphorus applications onclipping yield (Site D; tests Dl and D2;25 October 1978) •••••••••• j •••
The effect of two limestone applicationson soil pH (Site E; 1 November 1978) ••••
The effect of two limestone applicationson soil buffer pH (Site E; 1 November 1978)
The effect of three phosphorus applicationson available soil phosphorus (Site E;1 November 1978). • • • • • • • • • • • • ·
The effect of three potassium applicationson exchangeable soil potassium (Site E;1 November 1978). • • . • • • . • • • .,· •
The effect of three potassium applicationson percent potassium saturation (Site E;1 November 1978). • • • . • • • • • • • · •
The effect of two limestone applicationson exchangeable soil calcium (Site E;1 November 1978).. • • • • •
The effect of three potassium and twolimestone applications on percent calciumsaturation (Site E; 1 November 1978).
The effect of three potassium and twolimestone applications on percentmagnesiUm saturation (Site E;1 November 1978) •.•••• · . . . . . .The effect of two limestone and twonitrogen applications on tissuenitrogen (Site E; 26 May 1978). · . . . . . .The effect of two nitrogen and twophosphorus applications on tissuephosphorus (Site E; 26 May 1978) •• · . . . . . '.The effect of two potassium and twolimestone applications on tissuecalcium (Site E; 26 May 1978) . • • · . . . . . .The effect of two potassium and twolimestone applications on tissueiron (SiteEi 26 May 1978). • . • • · . . . . . .
xxiv
Page
246
246
247
247
248
248
249
249
250
250
251
251
252
Figure
162
163
Page
The effect of two limestone and twonitrogen applications on tissuemanganese (Site E; 26 May 1978). • .• 252
The effect of two potassium andtwo nitrogen applications on tissuealuminum (Site E; 26 May 1978) ••• 253
164 The effect of two potassium and twonitrogen applications on tissue .sodium (Site E; 26 May 1978) • • • • • • • •.••. 253
165
166
167
168
169
170
171
172
173
174
The effect of one phosphorus and onepotassium application on clippingyields (Site E; June 1977) ••••• 254
The effect of one phosphorus appli-cation on clipping yields (Site E;July 1977) • . • . • • • • •• • • • 254
The effect of one limesconeapplicationon clipping yields (Site E; September1977). . . . . . . . . . . . . . . . . 255
The effect of two phosphorus applica-tions on clipping yields (Site E;October 1977). • •.. • • • • . • • • • • 255
The effect of two potassium applicationson clipping yields (Site E; May and June1978). . . . . . . . . . . . . . . . . . 256
The effect of three potassium and twolimestone applications on clippingyields (Site E; july 1978) • • . • • 256
The effect of two limestone applica-tions on clipping yields (Site E;August 1978) • • • • • • • • • • • • 257
The effect of two limestone and twophosphorus applications on turfgrassquality (Site E; November 1977) .•• 257
The effect of two limestone applica-tions on turfgrass quality (Site E;June and July 1978). • • • • • • •• 258
The effect of two limestone applica-tions on red thread incidence (Site E;10 July 1978) ••••••••••••• 258
xxv
175 The effect of two nitrogen applica-tions on red thread and dollar spotincidence (Site Ei 1 July and 16July 1977 respectively).... • • • • • • • • • .
The effect of three nitrogen applica-tions on red thread incidence (Site Ei10 July 1978) ••• '••••••••••
Figure
176
177
Page
259
259
The effect ·of two limestone and twonitrogen applications on winter injury(Site E; 12 April 1978) ••••••.• . . . . . 260
178 The effect of three nitrogen applica-tions on dandelion encroachment (Site Ei28 August 1978). • • • • • . . • • • • • • • •• 260
179 The effect of two limestone applica-tions on soil pH (Site Fi 9 October1978) . . . . . . . . . . . . . _ ... . 261
180 The effect of two limestone applicationson soil buffer pH (Site F; 9 October
181
182
183
184
185
186
1978). . . . . . . . . . . . . . . . .. 261
The effect of two limestone applicationson exchangeable soil calcium (Site Fi9 October 1978). • • • • • • • • • • • • 262
The effect of two limestone applicationson percent calcium saturation (Site Fi9 October 1978) ..•••.•.••••• 262
The effect of three phosphorus applica-tions on available soil phosphorus(Site Fi 9 October 1978) • • • • • • • . 263
The effect of three potassium applica-tions on exchangeable soil potassium(Site Fi 9 October 1978) ••.•••• 263
The effect of three nitrogen and threepotassium applications on percentpotassium saturation (Site Fi 9 October1978). . . . . . . . .. . . . . . . . . . 264
The effect of two nitrogen applicationson tissue nitrogen (Site Fi 11 May 1978) 264
187 The effect of two nitrogen and twopotassium app.lications on tissuepotassium (Site Fi 11 May 1978). • • • • • • •• 265
xxvi
Figure Page188 The effect of two nitrogen and two limestone
applications on tissue calcium (Site F;11 May 19 78).• • • • • •• • • • • • • • • • • 265
189 The effect of two nitrogen and twophosphorus applications on tissuemanganese (SiteFi 11 May 1978) • • • • • • • •• 266
190 The effect of two limestone applica-tions on tissue manganese (Site F;11 May 1978) •• '•••••••• ' •••••• • •• 266
191 The effect of two potassium and twonitrogen applications on turfgrassquality (Site Fi April. 1978). • .• • • • •• 267
192 The effect of two nitrogen applicationson red thread incidence (Site F;27 May 19 78) • ." • • • • • • • • • • • • • • • •• 267
193 The effect of one limestone applicationon soil pH (Site Gi 30 May 1978). • • • • • • •• 268
194 The effect of one limestone applicationon soil 'buffer pH (Site Gi 30 May 1978) • • • •• 268
195 The effect of one limestone applicationon exchangeable soil calcium (Site Gi30 Ivlay 1978). • • • • • • • • • • • • • • • • •• 269
196 The effect of one limestone applicationon percent calcium saturation (Site Gi30 May 19 78). • • • • • • • • • . • • • • • • •• 269
197 The effect of two phosphorus applicationson available soil phosphorus (Site Gi3O'May 1978). • • • . • • • . • • • • • • • • •• 270
198 The effect of two phosphorus and twopotassium applications on exchangeablesoil potassium (Site Gi 30 May 1978) •• 270
199 The effect of two nitrogen and two potassiumapplications on percent potassium satura-tion (Site G; 30 May 1978). • • • • • • • • • 271
200 The effect of two phosphorus applicationson tissue phosphorus (Site Gi 5 June 1978). • •• 271
201 The effect of two phosphorus and twopotassium applications on tissuepotassium (Site Gi 5 June 1978) • • • • • • • •• 272
xxvii
Figure
202
203
Page
The effect of one limestone applica-tion on tissue manganese (Site G;5 June 1978). • . •.• •• • • • • • • · . . . . . 272
The effect of two limestone and threephosphorus applications on clippingyields (Site G; July 1978) •••••• · . . . . . 273
204 The effect of phosphorus applicationson turfgrass quality (Site G; July 1977and July 1978; after one and twophosphorus applications respectively) • • • • •• 273
205 The effect of one potassium and onelimestone application on turfgrassquality (Site G; July 1977) • • • • • • • • • •• 274
206
207
208
209
210
211
212
The effect of one potassium and onelimestone application on turfgrassquality (Site G; August 1977) • • • • · . . . . . 274
The effect of one limestone applica-tion on turfgrass quality (Site G;September 1977) • • • • . • . • • . • · . . . . . 275
The effect of two nitrogen applicationson He1minthosporium leaf spot incidence(Site G; 15 June 1978). • . • • • • • • • 275
The effect of three nitrogen applicationson crabgrass encroachment (Site G;5 September 1978) • . •. • • • • • • • • 276
The effect of two nitrogen and one lime-stone applications on soil pH (Site H;11 May 1978 •••••.••••••••• 276
The effect of two phosphorus applicationson available soil phosphorus (Site H; 11May 1978) • • • • • • • • • • • • • • • . 277
The effect of two nitrogen and twopotassium applications on exchangeablesoil potassium (Site H; 11 May 1978). · . . . . . 277
213 The effect of two nitrogen and twopotassium applications on percentpotassium saturation (Site Hi 11 May1978). • • • • • • • • • • • • • • • • • • • •• 278
xxviii
Figure
214
215
216
The effect of two nitrogen and twophosphorus applications on tissuephosphorus (Site Hi 5 June 1978) • •The effect of one limestone and twonitrogen applications on tissuemanganese (Site Hi 5 June 1978) •••The effect of two potassium and twonitrogen applications on clippingyields (Site Hi June 1978) • •• • •
xxix
e· • • • • •
Page
278
279
279
ACKNOWLEDGEMENTS
The author wishes to express his sincere apprecia~
tion to Dr. D. V. Waddington, whose guidance, labor, and
persistence throughout the duration of this project were in-
strumental in its success.
Appreciation is also extended to Drs. J. M. Duich,
T. L. Watschke, C. B. Smith, and J. K. Hall for their
suggestions and review of this dissertation.
Thanks are given to R. H. Fox, R. E. Manning, and
J. W. Whiteman for making plot space available on their
property and to Russell Fox, Elizabeth Turner, E. Randolph
Turner III, Rich Cooper, and Mary Long for their technical
assistance throughout the project. Thanks are also given
to C. R. Skogley for the loan of the sod strength equipment
used in several of these studies and to Bob Hummer for
donating sod for the sod establishment studies.
Much appreciation is also given to the O. J. Noer
Research Foundation,.whose financial support made the
development and completion of this project possible.
xxx
INTRODUCTION
Numerous turfgrass fertility studies have been con-ducted in the past .relating different rates of applied fertiliz-er to various types of turfgrass response. Types of response
,noted have included top growth, root growth, seedling growth,tillering, coLoz,«. disease resistance, heat, cold, and droughttolerance, weed encroachment, and species population changes.Although both beneficial and detrimental effects to differentrates of applied fertilizer were shown, most of these studieseither did not take into account initial soil nutrient levelsor were conducted under only one level of initial fertility.Since soil testing serves as the basis for making both estab-lishment and maintenance recommendations for application ofphosphorous, potassium' and limestone toturfgrass areas, moreextensive studies encompassing a larger range of conditions areneeded. The limited nature of most fertility studies is re-flected in the wide disparity that has been shown to exist amongturfgrass soil testing laboratory recommendations for mainte~nance and establishment fertilization (Turner, 1976). Recom-mendations for fertilization given by The Pennsylvania StateUniversity Merkle Laboratory are high compared with other labo;..ratories, and decreases in these recommendations without a lossof turfgrass quality may be possible. Therefore, calibrationstudies relating turfgrass response to different levels ofapplied nutrients on soil with different initial fertilitylevels are necessary so that meaningful interpretations of soil
2
test results and reliable fertilizer recommendations can bemade.
The objectives of this study were: .1) to relate t~rf-grass response during es.tablishment from seed, establishmentfrom sod, and maintenance to different levels of applied P, K,and limestone on soils with different initial levels of fertil-ity, 2) to use these results t:o determine optimum rates of P,K, and limestone for given initial soil fertility levels, and3) to use these results to evaluate and improve current Pennsyl-vania State University turfgrass establishment and maintenancefertilization recommendations. These studies were restrictedto home lawn, athletic field, and fai~ay type turfs. Furtherstudies need to be conducted for putting green and other closecut bentgrass areas as well as for highly modified, sandy soils.
LITERATURE REVIEW
Soil testing has served as the primary tool for deter-mining the fertility status of the soil and for predicting turf-grass nutrient requirements. The Pennsylvania State UniversityMerkle Laboratory alone analyzes approximately 7,000 to 8,000turfgrass soil samples annually. Despite the emphasis that hasbeen placed on soil testing for determining the phosphorus,potassium, and limestone requirements of turfgrasses, there hasbeen a noticeable lack of soil testing research directly appli-cable to turfgrasses. This lack of background resea'rch has re-sulted in a weakened soil testing program, as evidenced by thelarge differences that exist among turfgrass soil testing labora-tories in interpretation of soil test results and in the result-ing fertilizer and limestone recommendations.
In a survey of seven turfgrass soil testing laboratoriesin the Northeast, Mid-Atlantic, and North Central regions,Turner and Waddington (1978) found good agreement for soil testresults among laboratories using the same extracting procedures;however, for a given soil, maintenance recommendations varied byas much as 2.2lb p/lOOO ft2 (1.1 kg P/a), 5.0 lb K/lOOO ft2
(2.4 kg K/a), and 180 lb limestone/lOOO ft2 (88 kg limestone/a).Whereas The Penn State lab considered soil P low only if lessthan 65 ppm P, another laboratory using the same extracting pro-cedure considered soil P low only if less than 13 ppm P. Al-though most laboratories recommended liming if the soil pH fellto a range of 6.0 to 6.3, one laboratory did not recommend any
4
limestone at a pH value as low as 5.8 while The Penn State labrecommended liming when the soil pH dropped below 6.8. Thesedifferences among laboratories in turfgrass fertilizer and lime-stone recommendations, although certainly being affected bydifferent soils which may predominate in an area and by differ-ent climates, were probably in large part due to the lack ofdata specifically relating soil testing to turfgrass areas andthe dependence on research done with other agronomic crops suchas corn or pasture grasses.
Over twenty years ago, Fitts and Nelson (1956) statedthat the successful use of soil tests depends upon careful cali-bration of the tests with crop response to fertilizer and lime-stone applications. Hausenbuiller (1972) further stated thatcalibration studies designed for one crop cannot be expected toapply to another, nor can those for irrigated soils be appliedto non-irrigated soils. Bray (1961) believed that fertilizer
.experiments not designed for soil test correlation have no per-manent value. For these reasons, field fertility experimentsrelating turfgrass response to different rates of applied fertili-zer on soils with different initial fertility must be conductedif the reliability of turfgrass fertilizer and limestone recom-mendations is to be improved.
Various approaches have been taken in soil test cali-bration studies, but most use multiple regression techniques withresponse equations being generated. These equations can be usedto describe growth or other factors studied as affected generallyby fertilizer and limestone applications, and can be used to pre-dict the combinations of fertilizer and limestone which will give
5
a maximum or minimum response. Box and Hunter (1957) developeda series of experimental designs which have been successfullyused or adapted in agricultural research (Walker and Pesek,1963; Walker, Pesek, and Heady, 1963; Walker and Pesek, 1967;and Voss, Hanway, and.Fu11er, 1970). These designs allow theeffect of a greater number of fertilizer and limestone rates,along with their interactions, to be studied with a smaller num-ber of experimental units than standard factorial designs.Cochran and Cox (1957) discussed the use and advantages ofthese types of designs. Most of the problems of and approachesto calibration studies have been outlined by Hanway (1973).
Although no extensive calibration studies have been re-ported for turfgrasses';'much information has been reported whichrelates various types of turfgrass response to P, K, and lime-stone applications. Generally, however, these studies did nottake into account initial soil fertility levels, were conductedunder only one level of initial fertility, or were conducted inthe greenhouse using nutrient solutions, from which results aredifficult to apply to the field. Despite these drawbacks, theinformation gained from these studies may be of some value whencombined with field calibration studies in predicting turf-grass response to P, K, and limestone applications under avariety of soil conditions.
Phosphorus applications have generally been consideredvery important for turfgrass establishment, although the amountsneeded for different soil conditions has not been studied inany detail. Westfall and Simmons (1971) reported that on soilslow in available P, additions of P substantially increased
6
seedling density of Kentucky bluegrass (Poa pratensis L.),
whereas N applied without P did not improve seedling develop-
ment and reduced root weights. On soils with adequate P, N
applied alone increased rate of seedling development and quality.
On Pdeficient soils, McVey (1967) found that a Kentucky blue-
grass seedling growth response was caused by P rates as low as
0.016 lb P!lOOO ft2 (0.008 kg Pia) and response was linear,as
the rates were increased to 3.17 lb P/lOOOft2 (1.55 kg Pia).
Excellent seedling quality was achieved with rates ranging from, 20.13 to 1.58 lb p/1000 ft (0.064 to 0.773 kg pia). McVey (1968)
also stated that even on soils with high available P levels, P
additions caused a moderate response during the first two weeks
of bluegrass growth.
In the vegetative establishment of zoysia (Zoysia japon-
ica), a significant top, root, and stolon growth response to P
additions was obtained by Juska (1959) on a soil extremely low
in P. He concluded that adequate P was necessary for rapid
establishment of zoysia. Wood and DubIe (1976) found that P
affected St. Augustinegrass [Stenotaphrum secundatum(Walt.)
Kuntze.] growth most during the first 8 weeks of establishment.
At 8 weeks, coverage on plots receiving little or no P averaged
less than 50% whereas plots receiving 1.0 lb p/1000 ft2
(0.49 kg Pia) or more averaged 73% coverage. After 8 weeks,
the P rate had little effect on rate of coverage.
Juska, Hanson, and Erickson (1965), using P rates from
o to 1746 lb P/acre (19.6 kg Pia) added to the soil before
seeding, reported positive top growth and root growth responses
to P additions, although root weights tended to decrease at the
7
highest P rates. Common Kentucky bluegrass, 'Merion' Kentuckybluegrass, and creeping red fescue (Festuca rubra L.) respondedsomewhat differently, indicating different varieties andlor
species may have different P requirements. Merion root weights-increased with P rates up to 655 lb P/acre (7.4 kg Pia) beforedecreasing, whereas common Kentucky bluegrass root weights didnot change at rates greater than 218 lb P/acre (2.4 kg pia).
Top growth of Merion increased more rapidly and to a higherlevel with increasing P rates than common Kentucky bluegrass.An interaction occurred with P additions and soil pH. At a pHof 6.5, bluegrass and red fescue total plant growth showed lit-tle response to P appl,ications; however, at pH 4.5, bluegrassplant growth increased with P additions while red fescue wasstill unaffected. An interaction also occurred with P and Napplications with bluegrass top growth increasing with P addi-tions when N was applied, whereas when N was not applied, topgrowth only increased up to 218 lb P/acre (2.4 kg pia). Theauthors concluded that red fescue and bluegrass can toleratevery high levels of P without detrimental effects.
King and Skogley (1969) studied the effects of Pratesand placement on the establishment of a Kentucky bluegrass-redfescue mixture on soil with an initial P level of 0.25 kg Pia
(approximately 11 ppm). Turfgrass response to P rates rangingfrom 0.49 to 3.92 kg/a was inconsistent, with the effects ofestablishment fertilization lasting only a few months. Phos-pho-rus.levels did not affect the species composition of the turfor root weights. The average % P in the tissue 15 months afterseeding was.0.52%. Musser (1948) did find on an established
mixed b1uegrass-bentgrass turf a difference in species require-ment for P, with high P favoring a higher bluegrass population.
Some long-term benefits from seedbed P applicationshave been shown. With seedbed P applications ranging from 0to 6.8 kg P/aand resulting soil P levels which ranged from 6to 76 ppm, Turner, Waddington, andWatschke (1979) found that6 years after establishment spring greening was enhanced by theoriginal seedbed P applications and crabgrass (Digitaria spp.)encroachment was reduced. After 9 years, the seedbed P applica-tions resulted in greater top growth and reduced dandelion(Taraxacum officinale) encroachment.
Various turfgrass responses have been attributed to Pbeyond the seedling stage, although there are often conflictingreports. These differences, however, may be due to differentturfgrass species requirements or to interactions with othernutrients.
Hylton et a1. (1965) reported an increase in top growth,root growth, and tillering of Italian ryegrass (Lolium multi~florum) with P additions. Contrary to the conclusions of Juska,Hanson, and Erickson (1965), however, detrimental effects mayoccur with high P levels. Using a solution culture, Menn andMcBee (1970) found that high P levels caused a suppression ofgrowth. Bell and DeFrance (1944) reported that large amountsof P may reduce bentgrass root accumulation. Phosphorus wasalso reported by Holt and Davis (1948) to decrease bentgrassroot weights when a complete fertilizer was compared to onewithout P, although foliar coverage was increased. Phillipsand Webb (1971) suggested excessive P rates may accentuate
9
Many other factors that influence turfgrass qualityother than growth, however, may be affected by P applications.The incidence of several diseases has been shown to be influencedby P. Kentucky bluegrass turf fertilized with Nand P, NandK, or especially N, P~ and K was less diseased with stripe smut(Ustilago striiformis) than turf fertilized with N alone (Hull,Jackson, and Skogley, 1979), although this effect might bemodified by the availability of soil P and K. Goss and Gould(1968) reported that on a soil where P was not low, incidenceof fusarium patch (Fusarium nivale) was decreased by P at lowerN rates, although at higher N rates P had little effect. Goss(1969) also stated that P applications may have a significanteffect on the control of ophiobolus patch (Ophiobolus graminis),
10
and may interact with sulfur applications in this disease'scontrol (Davidson and Goss, 1972). Goss (1969) also statedthat N, P, and K additions interact on the incidence of redthread (Corticium fuciforme). Bloom and Couch (1960) found in-creased severity of brown patch (Rhizoctonia solani) under highN with normal P and K nutrition, but stated that increases inP and K could offset the increased susceptibility. Doliar spot(Sclerotinia homoeocarpa) incidence did not appear to be affect-edgreatly by P rates (Waddington et al.,1978), although some-what lower incidence was found where no P was applied.
Phosphorus may influence heat, cold, and drought toler-ance of turfgrasses. When temperatures and N levels are high,high P rates can cause further deterioration of Kentucky blue-grass turf (Pellet and Roberts, 1963). Goss (1963) reportedbetter bentgrass putting green quality in the hotter months onplots receiving no P, but better quality in the cooler monthswhere P was applied. Gilbert and Davis (1971) found that theaddition of P improved the cold tolerance of bermudagrassaslong as Nand K were in adequate supply. However, Palmertree,
.Ward, and Pluenneke (1974) did not find any effect of P on thecold hardiness of centipedegrass [Eremochloa ophiuroides (Munro.)Hack.]. Escritt and Legg (1969) reported that P additions con-tributed to the drought resistance of Poa annua L., as well asreducing moss invasion .. Keen (1969) has stated that when wateris limiting, small additions of P may considerably improveutilization of the limited H20 available.
Poa annua encroachment has been related to P additions.Waddington et ale (1978) found an increase in Poa annua in bent-
11
grass putting green turf as soil P increased from 12 to 94 ppmas a result of Pfertilization. Goss, Braver, and Orton (1975)also found an increase in Poa annua in a bentgrass putting greenwith higher P levels. Carrow and Rieke (1972) stated that highP may reduce the rate of arsenates used by Poa annua, thus de-creasing control by this chemical method.' Hansen (1969) re-ported that N applied without Por K resulted in higher weedpopulations than a fertilizer with N, P, and K; however, theapplication of P or K alone without N substantially increasedweed infestation. Sturkie and Rouse (1967) reported darker greenturf with no or low P. Pritchett and Horn (1966) stated thatparasitic nematode infestation of turfgrass roots decreased asP additions increased, even with adequate initial soil P levels.
Tissue P levels may also give some indication of whetherP is deficient. Bas.ed on a review of literature, Martinand Matocha (1973) outlined approximate sufficiency ranges fortissue P for cool season forage grasses. For Kentucky blue-grass, values less than 0.18% were considered deficient, from0.24 to 0.30% were critical, from 0.28 to 0.36% were adequate,and values greater than 0.40% were considered high. For annualand perennial ryegrass (Lolium perenne L.), values less than0.28% were deficient, from 0.28 to 0.34 were critical, from 0.36to 0.44% were adequate, and greater than 0~50% were high.Values ranging from 0.12 to 0.24% P were found in healthy blue-grass byOertli(1963). Lunt, Youngner, and Khadr (1964) re-ported a minimum tissue P level of 0.4% was associated withmaximum'yield of 'Newport' Kentucky bluegrass. Maximum yieldof Kentucky bluegrass was associated with a value of 0.25% by
12
Walker and Pesek (1967), although this value was dependent ontissue K levels. On a soil with only 12 ppm P, average creep-ing bentgrass tissue P levels of 0.50% were obtained, with nodeficiency noted or growth response occurring as tissue P in-creased to 0.84% due to P applications (Waddington et al.,1978).
Species and/or variety as well as time of sampling needto be considered in interpreting tissue P levels. Waddingtonand Zimmerman (1972) found higher P levels in creeping bent-grass (0.76%) and perennial ryegrass (O.7l%} than in Kentuckybluegrass (0.56%) or red fescue (0.54%). Butler and Hodges(1967) noted similar trends, but also found differences withina species. Whereas tissue P for common Kentucky bluegrass was0.27%, values for Merion Kentucky bluegrass were 0.49%. Criti-cal tissue P levels may be dependent on time of sampling.Hall and Miller (1974) found that 74% of the Merion Kentuckybluegrass clipping samples taken in July and September whichhad less than 0.36% P could be related to yields less than 50%maximum. In November; only 60% of the samples which had lessthan 0.23% P could be related to yields less than 50% maximum.
Potassium, according to Escritt and Legg (1969),follows Nand P in importance in turfgrass nutrition. Inactual field conditions, warm season grasses may generally showgreater response to K levels than cool season grasses.
Juska (1959) found a highly significant positive re-sponse to K applications during establishment of 'Meyer'zoysia for top growth and stolon growth and spread, and· statedthat adequate K was necessary for rapid zoysia establishment.
13
Pritchett and Horn (1962) reported that growth response ofwarm season grasses to K was generally species dependent, withthe K requirements of centipedegrass being relatively high com-pared to bermuda and zoysia. Pritchett, Nutter, and White(1957) inferred. from bermudagrass response that 125 to 175 ppmextractable K in the surface 3 inches (7.6 cm)was sufficientto maintai.n good quality bermuda putting greens, although Horn(1969) did not believe that the level of e·xtractable K foundin the soil was a good indication of the K available tobermudagrass.
With cool season grasses, growth response resultshave varied. On closely clipped bentgrasses, Bell and DeFrance(1944) found increasing K increased weight of accumulatedroots. Juska, Hanson, and Erickson (1965) reported greaterstimulation of root growth than top growth by K additions.Pellet and Roberts (1963) obtained greater Kentucky bluegrassfoliar growth in sand culture with high K; however, Monroe,Coorts, and Skogley (1969) obtained less growth of Kentuckybluegrass in sand culture with very high K and found the N:Kbalance could be important, although most growth parameterswere increased by moderate K additions. In sand culturestudies, Christians, Martin, and Wilkinson (1979) found thatmore K was needed to maximize bluegrass and bentgrass qualitythan tissue production. Also, as the K level increased, lessN was needed for maximum quality. They concluded that K mayplay a more important role in maintenance of turf quality thanpreviously thought, with the N:K balance of particular impor-tance. In a continuing field experiment with putting green
14
bentgrass, Waddington et ale (1972) obtained some growth re-sponse to K additions in the first 4 years of applications,but generally obtained little or no response compared to 0 Kplots (soil level 0.06 meq K/lOOg) from the sixth year on(Waddington et al., 1978); however, early spring chlorosis was
noted on 0 K plots during two of the years, with the effectdisappearing after 10 to 14 days.
Growth response differences by bluegrass and bentgrasstoK levels may be due to their ability to utilize soil K.Potassium uptake at low levels of soil K has been shown to beclosely correlated with root CEC, with bentgrass having astronger attraction and uptake of K than bluegrass (Gray,Drake, and Colby, 1953). Colby and Bredakis (1966) questionedthe value of soil tests for determining the need of K fertiliza-tion of bent species due to the strong capacity of bentgrassesto utilize potassium from mineral sources in the soil.
Direct and indirect effects of K applications on turf-grass quality are more important than their effect on growth.Incidence of several diseases has been related to K applications.Leaf spot (Helminthosporium spp.) disease of bermudagrass hasbeen shown to be much more severe where soil K has been keptlow (Evans, Rouse, and Godaukis, 1964; Juska and Murray, 1974).
Dollar spot of bermudagrass was reported by Horn (1969) to bereduced by K applications up to 2.5 lb K/lOOO ft2 (1.2 kg Kia>and was also found by Juska and Murray (1974) to be reduced byK additions. Markland, Roberts, and Frederick (1969) reportedthat increased bentgrass foliage K reduced dollar spot incidence,although Waddington et ale (1978) did not find any significant
15
effect of K additions on dollar spot incidence of bentgrass,despite a range of soil K of 0.06 to 0.28 meq/lOOg and a rangeof tissue K of 1.74 to 2.63% K. In the same test, Waddingtonet ale (1978) found an: increase in brown patch with increasingK. Fusarium patch (Fusarium nivale) was reported to be de-creased by K when low rates of N were applied but had no effectat higher N rates (Brauen et al., 1975). Goss and Gould (1968),
however, reported that the addition of K in the absence of Pgenerally increased the incidence of fusarium patch. Goss (1969)
also related reduced incidence of red thread and Ophioboluspatch to K applications. Goss and Gould (1967) stated that aK deficiency and high N treatments can cause an accumulation ofnonprotein nitrogen and unused carbohydrates, with the re-sulting high concentration of sugars and nitrates being afavorable media for growth of disease organisms.
Potassium plays a role in drought and heat tolerance,and especially cold tolerance of warm season grasses. De-creases in winter injury or increases in winter hardiness dueto increased K levels have' been reported for bermudagrass(Adams and Twersky, 1960; Alexander and Gilbert, 1963; Gilbertand Davis, 1971; Juska and Murray, 1974) and for centipede-grass (Palmertree, Ward, and Pluenneke, 1974). Beard andRieke (1966) stated thatturfgrass winter survival was at amaximum when K rates were about 1/2 that of the N rate. Cookand Duff (1976), however, did not find a substantial effect ofK on freezing tolerance of tall fescue (Festuca arundinacea).
High N coupled with high K was shown by Pellet andRoberts (1963) to give better heat resistance to Kentucky blue-
16
grass than high N and low K. Waddington et ale (1978) foundthat bentgrass wilting was more severe where no K had beenapplied; however, DiPaola and Engel (1976) found no importantbenefit from K applications on the desication resistance ofbentgrass. Escritt and Legg (1969) reported that on plots re-ceiving only Nand P, no K deficiency was observed until after20 years when drought resistance was decreased.
Other responses attributed to K additions includewear tolerance and Poa annua encroachment. Shearman and Beard(1975) reported bentgrass wear tolerance improved significant-
-ly with K additions in the range of 2.7 to 3.6 kg K/a/season.Hawes and Decker (1977) found no significant effect of K onhealing potential of bentgrass; however, initial soil K levelswere high. Waddington et ale (1978) reported an increase ofPoa annua encroachment into bentgrassas soil K increased from0.06 to 0.28 meq K/lOOg due to K fertilization.
As with P, tissue K levels may give some indicationof whether K is deficient. For Kentucky bluegrass forage,Martin and Matocha (1973) classified values less than 1.5% asdeficient, values between 1.6 and 2.0% as critical, valuesbetween 2.0 and 2.4% as adequate, and values greater than 3.0%as high. For annual and perennial ryegrass forage, theyclassified values less than 2.1% as deficient, values between2.6 and 3.0% as critical, values between 3.0 and 3.5% as ade-quate, and values greater than 4.5% high. Lunt, Youngner,and Khadr (1964) assoc.j.ateda minimum K value of 1.0% withmaximum yield of Kentucky bluegrass. Walker and Pesek (1967)associated a value of 1.74% K with maximum bluegrass forage
17
growth, with this value being dependent on theP level.Waddington et ale (1978) obtained creeping bentgrass tissue Klevels as low as 0.58% K, with some chlorosis occurring,whereas no chlorosis was observed on this date on plots with1.04% tissue K.
The importance of the effect of date of sampling maylimit the use of tissue K levels for predicting deficiencies,as evidenced by the data presented by Davis (1969), Hall andMiller (1974) and Waddington et ale (1978). Significant spe-cies and variety differences in tissue K have also been shownto exist (Butler and Hodges, 1967; Waddington and Zimmerman,1972), which thus must also be considered in interpretingtissue K results.
Soil reaction and calcium nutrition have been shownto have various effects on turfgrass performance, althoughthere are still differing opinions on optimum soil pH ranges.Musser (1962) outlined what he considered to be optimum soilreaction ranges for various turfgrass species as follows:
optimumSpecies Soil Reaction
Kentucky bluegrass 6.0 - 7.6annual bluegrass 5.1 - 7.6creeping red fescue 5.3 - 7.6bentgrass 5.3 - 7.5ryegrass 5.4 - 8.1zoysiagrass 4.5 - 7.6bermudagrass 5.1 - 7.1.
18
Based on research conducted since the late 1950's, how-ever, these ranges could probably be refined. Juska, Hanson,and Erickson (1965) found that although red fescue performedbetter than Kentucky bluegrass at a soil pH of 4.5, both'per-'formed better at a pH of 6.5, with root, rhizome, and clippingyields higher at the higher pH. Juska and Hanson (1966) re-ported greater root yields of Poa annua on a loamy sand at apH of 6.5 versus 4.5, although there was no difference on asilt loam. Palazzo and Duell (1974) reported that Kentuckybluegrass varieties produced maximum growth in a pH range of6.0 to 6.5, perennia1 ryegrass at 6.0 to 6.4, and tall fescueat 6.0 to 7.0.' All of these species decreased in growth abovea pH of 7.0. Red fescue growth was found to decrease linearlywith limestone applications as the pH increased from 4.2 to7.6. Murray and Foy (1978) found cultivar as well as speciesdifferences in response to soil acidity, suggesting that'rather than liming, cultivars might be developed that areadaptable to low soil pH and especially resulting Al toxicity.Contrary to Palazzo and Duell (1974), they found a positiveyield response to 'fine-leaved fescue as the soil was limedfrom a pH of 4.3 to 5.7, although 11 of 15 cultivars madeadequate growth at the lower pH. Tall fescue was more sensi-tive to soil acidity, with greater growth occurring at a pHof 5•.7 than 4.3•
Nittler and Kenny (1971) also found wide differencesin Kentucky bluegrass cultivar tolerance to low Ca, with
,'Arista', 'Fylkirig', 'Cougar', 'Zwartburg', and 'Pennstar'more tolerant than 'Newport', 'Windsor', 'Nugget', and 'Delta'.
19
Lundeberg, Bennet, and Mathias (1977) found that bermudagrassgrown on' strip mine spoil with a pH of 2.9 exhibited increasesin root growth and forage yields as liming raised the pH to 3.8,
but liming to a higher pH caused no, further increase in forageyield and reduced root yields. They concluded that bermuda-grass could tolerate very acid conditions (pH 3.4) and thatthe toxicity of certain elements rather than the direct effectof low pH limits bermudagrass growth. Juska (1959) reportedan increase in stolon, root, and top growth of 'Meyer' zoysiaas soil pH was raised by liming from 4.7 to 6.1, and con-cluded that this zoysia cultivar could b~_expected to performbetter and to develop a better turf in less time with a soilpH range of 6.0 to 7.0. Turner, Waddington, and Watschke(1979) found greater growth and tiller density of 'Merion'Kentucky bluegrass at a soil pH of. 5.6 and soil Ca level of4.1 meq/lOOg than on the same soil limed to a pH of 6.4 andsoil Ca level of 6.1 meq/lOOg. These studies point out thedifferences in'species and even cultivars in response to soilacidity and the need for adjusting liming practices according-ly.
Soil reaction and liming can also affect turfgrassperformance and quality in ways other than growth. Couch(1965) stated that Ca exerted a more pronounced effect on turf-grass disease susceptibility than any other nutrient, althoughthis statement apparently was based on nutrient solution andsand culture experiments rather, than actual field results(Bloom and Couch, 1958; Bloom and Couch, 1960; Couch andBloom, 1960; Moore, Couch, and Bloom, 1961). Couch (1973)
20
further stated, however, that plant response to a pathogen isa complex factor of both soil pH and nutrient combinations andthat predictions of disease development based on pH alone areuseless. Musser (1962) stated that dollar spot and brownpatch incidence could be aggravated by excessive soilaciditYihowever, Ledeboer and Skogley (1967) found greater incidenceof dollar spot onbentgrass when 24.4 kg limestone/100m2 wasapplied than when none was applied.
Turner, Waddington, andWatschke (1979) reported lessdandelion (Taraxacum officinale) encroachment into MerionKentucky bluegrass on soil with a pH of 5.6 than on soil limedto pH 6.4. Kentucky bluegrass thatch, which can affect turf-grass quality in several ways, has been reduced by maintaininga pH of 7 and applying limestone in the spring and fall(Murray and Juska, 1977). However, Smith (1979) found thatliming in combination with other management practices did notadequately control bermudagrass thatch on a putting green andLedeboer and Skogley (1967) found no effect of limestoneapplications on thatch decomposition.
Due to species differences in preferred soil reaction,proportion of species in turfgrass mixtures could be affectedby soil pH. Musser (1948) found the proportion of Kentuckybluegrass in a Kentucky bluegrass-bentgrass. turf was higherunder low acidity, with bentgrass showing a wide range oftolerance to soil pH. The influence of soil reaction may inmany cases be due to its effect on the availability of othernutrients. Snyder and Burt (1975) reported observations ofMn deficiency in bermudagrass in soils with high pH due to
21
decreased Mn solubility.
This review shows that soil levels of P and K and thesoil reaction as well as additions of P, K, and limestone canbe expected to influence turfgrass growth and quality. However,it also points out that there is not nearly enough informationrelating turfgrass response to fertilizer and limestone appli-cations on a variety of soil conditions in the field to beable to predict responses that might be obtained. Since thisability to predict the nature and i~portance of benefits fromfertilizer and limestone applications to a soil is the ulti-mate objective of a soil test, numerous studies relating turf-grass response to fertilizer and limestone applications forsoils with different inherent fertility under a variety ofconditions need to be conducted. The result would not only bea strengthened soil testing program, but more efficient use offertilizer and limestone materials.
GENERAL METHODS AND MATERIALS
Th~ following methods and materials were used for mostor all of·the experiments in this study. Thus, to avoid dis-cussing them in the methods and materials for each individualexperiment,· they are referred to only in this section.
Soil AnalysisThe fertility status of all soil samples was determined
at The Pennsylvania State University Merkle Laboratory bychemical tests as outlined by Hinish (1973), with the exceptionof modifications described for soil P and pH. Soil samples,with thatch removed, were air dried, crushed, and sievedthrough a2-mm 'screen. Mineral and organic matter not passingthrough the screen were discarded. Scoops were used to take anassumed weight of S.Og soil for pH and buffer pH (pHB) deter-minations and 2.Sg soil for Ca, Mg, and K determinations.Before October 1978, a scoop taking an assumed weight of 3.S7gsoil was used for P determinations; however, after this datea 2.Sg scoop was used.
Chemical tests consisted of determining pH using a 1:1soil-water paste; buffer pH (from which the lime requirementwas calculated) using Woodruff's solution in the soil to solu-tion ratio of 1:2; and Ca, Mg, and K using IN NH40AC bufferedat pH 7.0 in the soil to extracting solution rat~o of l:ln.Due to a change in depth of electrode placement, pH values of0.2 to 0.3 pH unit less were obtained after January 1978(Long, 1979). Bray No.1 extractant was used for P determina-
23
tions, with a soil to extracting solution ratio of 1:7 beingused before October 1978 and a ratio of 1:10 being used afterOctober 1978. Higher soil P levels were measured for a givensoil after October 1978 due to this procedural change. Long(1979) found an average increase in soil P of 40% due to thechange in soil to extracting solution ratio, although theactual magnitude of increase varied considerably with differ-ent soils.
Elemental Tissue AnalysisAll tissue samples were analyzed at The Pennsylvania
University Plant Analysis Laboratory. Tissue samples weredried at 60-70 Cand were ground in a Wiley mill using a 20-mesh screen. Nitrogen was determined by Kjeldahl analysisand all other elements (P, K, Ca, Mg, Mn, Zn, Cu, AI, B, andNa) by anopt~cal emission spectrometer (Baker et al., 1964).In the Results and Discussion sections, emphasis has beenplaced on N, P, K, Ca, and Mg.
Phosphorus, Potassium, and Limestone SourcesThe P, K, and limestone sources used for all experi-
ments were triple superphosphate (44% P205)' muriate of potash(60% K20), and granular limestone. Specifications for thegranular limestone were as follows:
1) chemical analysis: calcium oxide - 48%magnesium oxide - 4%total oxides - 52%CaC03 equivalent - 95.6%
24
2} physical analysis: passing 16 mesh -" 20 II
" 60 "" 100 "
100%98%45%30%
~urfgrass Quality RatingsTurfgrass quality was rated periodically on all
studies using a scale of 0 to 10 with 0 representing deadturf and 10 representing best possible quality. Ratings re-presented a visual composite assessment of the overall condi':"tion of the turf and included factors such as turfgrass uni-formity, density, and color.
Experimental DesignA central composite rotatable design was used for all
experiments. Response surface techniques, such as the com-posite designs, provide a more economical and feasible meansthan a standard factorial experimental design for determiningcombinations of fertilizer and timestone which provide optimumresponse under a variety of conditions. The use and advantagesof composite designs have _been discussed by Cochran and Cox(1957). Composite designs have been used successfully tostudy agronomic and forage crop response to N, P, and/or Kapplications (Walker and Pesek, 1963; Walker, Pesek, andHeady, 1963; Walker and Pesek, 1967; and Voss, Hanway, andFuller, 1970) and recently has been used for nutrient solu-tion studies for turfgrasses (Christians, Martin, and Wilkin-son, 1979).
Using this experimental design with regression analy-sis, response equations are generated, which can then be used
25
to produce a response surface and to predict optimum responsegiven a certain combination of applied nutrients. Severalpoints should be kept in mind when using the response equationsand studying the responses discussed in this text:
1) to calculate a response, the coded values for thefertilizer and limestone rates, not the actualrates, should be substituted into the responseequation;
2) all responses discussed in the text, unless other-wise specified, are the predicted values generatedfrom the response equations;
3) predictions should not be extrapolated beyond therange of fertilizer and limestone rates used in .each experiment;
4) when maximum or minimum response values are dis-cussed, they are generally closely approximatedvalues rather than precisely calculated maxima orminima;
5) a 5% level of significance was generally used toevaluate the regression coefficients.