TECHNICAL BULLETIN 113 ISSN 0070 - 2315

PHOSPHORUS AND POTASSIUM FERTILIZING OF LUCERNE

P. I. Orphanos

I R _

~ C E I V E D!

I 2 1 SEP 1990

II: AC \{IC. ULTURAL I\bEA.RCHI INSf I rUTE '--'_;';'; _._ . - __ - .. __ I

.

I

AGRICULTURAL RESEARCH INSTITUTE MINISTRY OF AGRICULTURE AND NATURAL RESOURCES

CYPRUSNICOSIA

JANUARY 1990

PHOSPHORUS AND POTASSIUM FERTILIZING OF LUCERNE

P. I. Orphanos

SUMMARY

The results are presented of a PK fertilizer experiment in which 20, 40, 60, or 80 kg P ha-1 in combination

with 0, 220, or 440 kg K ha-1 were tested with lucerne (alfalfa) grown on plots of known fertilizer history at

Morphou Government farm over the period 1969-72. A rate of 60 kg P ha-1 was sufficient for maximum yield

(about 20 t DM ha-1 in the second year) irrespective of initial soil P status (1.2, 3.8 or 13.9 ppm NaHC03-P in the

0-15 em soil layer) but K did not influence yield (lowest NH40Ac -exchangeable K value in the 0-15 ern soil

layer 185 ppm). By the end of the 4-year period over which the experiment lasted, the initial NaHC03-P values

in the 0-15 ern soil layer were smoothed out to values governed by the currently applied P (5.0,7.2,8.2 and 9.9

ppm for the 20, 40, 60 and 90 kg P ha-1 rates, respectively) . The fact that with the 60 kg P ha-1 rate as much P

was removed with the matter harvested as was applied, and yet NaHC03-P in the 0-15 em soil layer increased.

indicates that appreciable amounts of P were taken up from deeper soil layers. Increasing P fertilizing increased

P concentration in the DM harvested to about 0.3%, slightly decreased K concentration, but did not influence N

concentration. Similarly, increasing K fertilizing increased K concentration in the DM harvested from 1.5%

without K fertilizing to 3.0% with the 440 kg K ha-1 rate, and N~OAc -exchangeable K in the 0-15 soil layer

from 197 to 590 ppm. One ton of the DM harvested contained 35 kg N, 3.0 kg P and 25 kg K.

nEPIAHlJIH

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nou EYWE xa'ta rnv :n:EQtOOo 1969-n O'tTJV KUI3£QvTJ'tLXtj E:n:all).TJ M6Q<POll OE 't£!1<iXLa yv<OO'tou L<TtOQLc

xou )'!JtavOTJ~. .1.oxL!1<iO'tT\XaV OE 6). Oll~ 'tOll~ ~llva'tou~ oUV~llaO!LOU~ OL MOEL~ 20, 40, 60 XaL80

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yLa 'tTJ jW(LO'tTJ ~uva't\:n:<XQaYwytj (20 't6vOL ~TJQtj~ ollota~ /EX'tCtQLO xa'ta 'to ~M£QO E't~) ave;CtQ'tTJ'ta

wt6 'to <XQXLx6 £:1t!JtEbo cpcooq>6QOll 0't0 EOOq>o~ (1.2, 3.8 tj 13.9 !L.a.E. P 0't0 £:1tLlpaVELmOO EOOq>o~ (0-15

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:n:aQaywytj (to :n:LO XaIlTJA.6 :n:006 EVaU~LJ1Oll K !1£ 0~Lx6 allJ1CbvLo O'ta £:1tLlpaVELaxa 15 EX. EMq>o~

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X"A.YQ. P/EX'tCtQLO). To YEyov6~ 6tL xU'tw wt6 'tTJ M OTJ t urv 60 xAYQ. P/EX'taQLo :n:<XQ6"A.0 rrou alpaLQE6T\­

xcv !1£ 'tTJ XOQ'to!1<i!;a 60 X"A.YQ· P TJ 'tLlltj t ou NaHC03-P 0't0 £:1tLlpaVELmOO O'tQWIUl EMq>o~ all~6TJXE

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%, e>..a'ttwOE E"A.aQJQa 'tTJV :1tEQLEX'tLx6'tTJ'ta XaAtOll, aUa bev £:1tTJQEaoE 'tTJV :n:EQL£XtLX6'tl'I'ta atw'toll.

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'to!1cita a:n:6 1.5% XWQL~ xaALOUxO ).!JtavOTJ OE 3.0% !1£ 440 XL"A.YQ. K!EX'tCtQLO, XaL 'to evall~LJ1O x<iA.L

o'ta £:1tLcpavELaxa 15 EX. EMq>oll~ wt6 197 OE 590 u.c.e. Eva~ 't6vo~ ~TJQtj~ X<XQ'to!Lcita~ 7t£QL£tXE 35

X"A.YQ. al;w.ou, 3 xAYQ. cpcooq>6QOll xaL 25 xAYQ. XaAtOll.

3

INTRODUCTION

Lucerne (alfalfa) has never been a major crop in Cy­prus. It is presently grown on about 700 ha, mostly on

cattle farms, for the production of hay. In the last 20

years it has been irrigated by conventional sprinklers and more recently by permanent low-angle, low-capacity

sprinklers.

Lucerne is generally acknowledged to be an efficient

fixer of atmospheric N (Burton, 1972), hence only a starter N rate of 30-40 kg N ha-l is applied at sowing (Rhykerd and Overdahl , 1972). However, as all Cypriot

soils are inherently very low in P (less than 3 ppm NaH­C03-extractable P), fertilizer P must be routinely applied unless residual fertilizer P has accumulated in the soil, which is a common occurrence in irrigated soils. Unlike

P, K is abundant in Cypriot soils (about 300 ppm N~OAc- exchangeable K), except those in the igneous hilly Troodos massif. Only where irriga ted crops have

been grown for long years on the same soil without K fertilizing will K have decreased (Krentos and Orphanos,

1979).

The present work comprised a PK experiment, which

was carried out over the period 1969-72 at Morphou Government Farm on plots of known fertilizer history.

Belated report ing of the results is warranted because the technology of lucerne growing and the variety grown

have not changed since the experiment was carried out, therefore the results are still applicable.

MATERIALS AND METHODS

The plots used were of known fertilizing history since 1933. They were cropped with irrigated wheat continual­ly over the period 1933-51 under varying NP fertilizing,

the effects of which over the period 1934-44 were report­

ed by Littlejohn (1946). However, no other comprehen­

sive results have since been reported. From 1952 on­wards the plots were used to test combinations of PK rates with potatoes, lucerne and maize. The last crop was lucerne grown over the period 1965-68 under three rates

of P (15, 30 and 45 kg P ha-l supplied as single super­

phosphate or as basic slag) in combination with three rates of K (0, 60 and 120 kg K ha-l, supplied as potas­sium sulphate) (ARI, 1967, 1968, 1969). No P or K fer­

tilizer was applied in 1968, i.e. the year preceding the

year of initiation of the present experiment. Available P and exchangeable K at the end of 1968 are presented in

Table 1. The soil was an alluvial loam fairly uniform to a

depth of 150 em, and contained 8% CaC03 throughout

the profile.

The 36 plots (each measuring 4.9x9.2 m) of the above experiment [2 P carriers (single superphosphate, basic slag)x 3 Prates (15, 30,45 kg P ha-l)x 3 K rates (0,60, 120 kg K ha-l)x 2 replications] were grouped on the basis

of P rate, irrespective of P carrier, in three blocks (repli­cates) for the new experiment. Of the 12 plots of each

replicate 4 plots had been under Ko, 4 under KI and 4 under K2• In each of these tetrads four Prates (20, 40, 60, 80 kg P ha-l ) , applied as triple superphosphate (0-48-0),

were randomized. The K treatments were retained but the rates of K applica tion were increased to 0, 220 and

440 kg K ha-l. In this way any residual effects of the pre­vious P rates would be removed as block effects.

Starter N (30 kg N ha-l as ammonium sulphate) was ap­

plied and lucerne was sown on 15 May 1969. The variety used in this, as also in the above-mentioned experiment, was Local (considered to be Provence C-52-3 introduced in 1955), which has not yet been outyielded by any new introduced variety (Droushiotis, 1985). In the first year,

P fertilizer was applied broadcast in doses of 20 kg P ha-l

on 5 June, 14 July (after the 1st cutting), 26 August (after the 3rd cutting), and 15 September (after the 4th cutting). All plots received P on 5 June, only P2, P3 and P4 plots re­

ceived P on 14 July, only P3 and P4 plots received P on 26 August and only P4 plots received P on 15 September. Fertilizer K was applied in a similar manner on 26 Au­

gust and 15 September. This, of course, introduced con­founding of fertilizer rate and ti'!1ing of application. The

situation was rectified from the second year onwards by applying the fertilizers in two equal split doses, in early May and early July.

4

The experiment was irrigated by sprinklers over the

practically rainless period May-October (Table 2) when­

ever about 40 mm of evaporation from the Class A pan had accumulated (every about six days in June-July).

However, often irrigation had to be given even in March

and November. At each irrigation an amount of water

equivalent to 0.8 of the pan evaporation which accumu­

lated since the previous irrigation was applied. Under

this semiarid environment (Table 2), the yearly amount

of water applied was about 950 mm, which is close to the

average recommendation of Metochis (1980), who also

found that irrigating once after each cutting is frequent

enough.

Cutting was done at full flowering (about 11 cuttings!

year), which occurred every 20 days during the summer

months. During December-February, when lucerne does

not flower, the cutting interval was 50 days, and the

cutting was done when new shoots started appearing on

the crown; for the rest of the year, cutting interval was

intermediate. This agrees well with the cutting schedu le

recommended by Droushiotis (1980b). Samples of har­

vested material were taken at every other cutting for de­

termining dry matter and NPK content

The data were analyzed using the analysis of variance

procedure.

RESULTS AND DISCUSSION

As expected, overall yield was highest in the second

year and declined in the third and fourth year (Fig. 1).

Under sufficient P fertilizing (60 kg P ha- l ) yield was

high (20 t DM ha-l in the second year). As K fertilizing

had no effect on yield, the data presented are averages

over the three K rates.

Even though the experiment was not designed to test

the residual effect of the P applied to the plots over the

period 1960-67 (see soil P data in Table I), an impres­

sion of such effect could be obtained (Fig. 1) by compar­

ing the effect of c~ently applied P among the three rep­

licates (previous P treatments; Table I) using the K

treatments as replicates, Clearly, in all cases, particular­

ly in the second and third year, such residual effect was

marked, especially under the two lower rates of current P

application (20 and 40 kg P ha-l ) , which were insufficient

for maximum yield. Moreover, it is even clearer that 60

kg P ha-l ensured maxim~m yield irrespective of initial

soil P status (1.2 to 13.9 ppm NaHCOrP). It can be cal­

culated from the yield data (Fig. I) and P concentration

in the harvested material (Fig. 2) that with the 60 kg P ha-l rate, which gave maximum yield, as much P was re­

moved as was applied.

Table 1. NaHC03-extractable P and NH40Ac-exchangeable K in the (urface soil layer (0­

15cm) of the experimental plots as affected by previous P and K fertilizing. (Soil.. sampled on 22 July 1968; new experiment sown on 14 May 1969).

K rate (kg K ha-l )

Carrier and rate

(kg P ha") 0 60 120 0 60 120

Superphosphate ---- NaHCOrP(ppm) -... ----- ~OAc-K(ppm)

15 0.8 1.0 0.6 190 250 338 30 4.0 1.9 3.9 210 228 280 45 8.0 7.2 7.7 193 255 293

Basic slag

15 3.7 0.4 0.7 213 275 345 30 5.0 3.1 4.7 193 230 238 45 20.0 20.4 2004 185 235 300

5

Neither P nor K application significantly affected the

dry matter content of the harvested material, which var­

ied among cuttings from 19 to 24%, but was mostly

close to 22% (Fig. 3~ Under the more harsh environment

of Athalassa, Droushiotis (1980a) reported consistently

lower dry matter content during the winter months.

At the end of the experiment, NaHC03-P in the surface

0-15 em soil layer settled at values proportional to the

current P rates applied, irrespective of soil P status at the

start of the experiment (Table 3). This indicates the over­

riding influence of freshly applied P. It must also be not­

ed that NaHC03-P in the 0-15 CAl layer increased during

the course of the experiment even with the two lower P

rates, i.e. 20 and 40 kg P ha" (Table 3), even though

these rates were insufficient for maximum yield. This,

combined with the fact that almost as much P was re­

moved with the harvested material as was applied, indi­

cates that appreciable amounts of P were taken up from

deeper soil layers.

Levin et al. (1969) reported no response to P over a 3­

year period with a soil testing 15 ppm NaHC03-P in the

top 20 cm layer. Likewise, Havlin et al. (1984) did not

obtain a response to P over a 6-year period with a soil

testing 14 ppm NaHC03-P in the top 30 em layer. In

connection with the latter work, Fixen and Ludwick

(1983) reported a sharp decline in NaHC03-P in the 0-30

em layer, to 3.7 ppm by the end of the third year, in plots

that did not receive P. An annual application of 50 kg P ha" was sufficient to maintain the soil P at its initial val­

ue (Havlin et al.• 1984). In the light of this, it is evident that with a high P-requiring crop like lucerne, unless soil

P is higher than 14 ppm an annual application of 60 kg P ha" is required maintain high yields. However, if soil P

has been increased in deeper layers, as a result of inten­

sive P fertilizing and irrigation, the P rate may have to be

adjusted accordingly.

Increasing P rate proportionally increased P·concentra­

tion in the dry matter harvested to 0.25-0.30%, it had no

effect on N concentration, but slightly decreased K con­

centration (Fig. 2), this possibly being a dilution effect.

Similarly, rates in excess of 40 kg P ha" decreased Zn

concentration from 29 ppm to 19 ppm (Table 4), but did

not influence Mn, Cu or Fe concentration.

Table 2. Average air temperature, rainfall and Class A pan evaporation at the ex­

perimental site (Morphou).

Mean daily air

temperature (DC) Class A

--------------------- Rainfall pan evaporation

Month Maximum Minimum (mm month") (mm day! )

January 15.7 5.8 69 1.2

February 16.4 5.4 45 1.7

March 18.7 6.4 44 2.7

April 22.8 8.2 12 4.2

May 27.0 12.3 8 5.9

June 30.7 16.0 2 7.6

July 33.0 18.6 0 7.6

August 33.7 19.2 0 7.0

September 30.7 17.0 5 5.6

October 26 .8 13.4 27 3.4

November 23.1 10.4 29 1.9

December 17.6 7.6 74 1.3

YEARLY TOTAL 315mm 1530mm

6

24

20 r 0 s: 16.:: "0 Qj ";;..

~ C; E

0 >.

4

0

Table 3. NaHCOrextractable P in surface soil samples (D-15cm) at the end of the

experiment (28 November 1972), i.e. after four annual applications of the indicated P rates, versus the values recorded 10 months before the experiment was started. (Each value is a mean of three plots under each of the three K rates).

P rate over the period

1969-72 NaHCOJ - P (ppm) l)(kg P ha·1year·

Replicate" 22 July 1968 28 Nov. 1972

20 I 1.2 5.1 II 3.8 4.9 III 13.9 5.1

40 I 1.2 .7.2 II 3.8 6.6 III 13.9 7.~

60 I 1.2 9.9 II 3.8 8.9 III 13.9 8.9

80 I 1.2 10.2 II 3.8 10.3 III 13.9 9.2

• Each replicate comprised plots which received over the period 1%5-67 15,30, or 45 kg P ha"; "respectively for I, II, and III.

~

2424 1971 1972

20

1969

20 x

16 16

12 x

I P8 I P I P IsIs I 5 44I P . s IP.sI P. 5

4

0 00 20 40 60 80 20 40 60 80 20 40 60 80 20 40 60 80

Prate (kg P ha-1 )

Figure 1. Lucerne DM yield over the period 1969-72 as residual NaHC03 -P in the 0-15 em layer:. 1.2 ppm

influenced by freshly applied P, and residual soil P o x

3.8 ppm 13.9 ppm

( cf. Table 1). Vertical bars denote LSDs (P=O.05)

for comparing means of freshly applied phosphor­

us (P), residual soil phosphorus (S) and the P x S

combinations. 7

Equally high yield as that obtained in the present ex­periment (20 t OM ha? with 60 kg P ha") has also been

reported for other areas in Cyprus, i.e, Athalassa (Meto­

chis, 1980; Metochis and Orphanos, 1981; Droushiotis,

1985) and Akhelia (ARI, 1971, 1972). From the nutrient

concentrations in Fig. 2, it can be calculated that this

yield of 20 t OM ha" contains 700 kg N, 60 kg P and 500

kg K, or 35 kg N, 3 kg Pand 25 kg K per ton OM. Such

N content is equivalent to 220 kg crude protein per ton

OM

Lack of response to K fertilizing was to be expected, as

Havlin et al. (1984) reported no response over a 6-year

period even at 126 ppm ~OAc-K in the 0-30 em layer.

In Cyprus the only response to K obtained so far has

been with potatoes at 222 ppm NI-40Ac -K in the 0-15 cm layer (Krentos and Orphanos, 1979). However, K ap­

plication markedly increased K concentration in the dry

matter harvested (Fig. 4) but decreased Mg concentration

(Table 4). It also increased NI-40Ac-K in the 0-15 em

soil layer from 197, 246 and 299 to 194, 342 and 590

ppm with the 0, 220 and 440 kg K ha" rates, respectively.

4

3

2

3 Jan 10Feb 29 Apr 22 Jun 10Aug

55 1970 1971

4

z ';/!

0.4

0.3

o, 0.2

0.1

o 29 Mar 11 Jun 26Jul 6Sep 4 Nov

4

Dff1lffjl20 40 60 80 kg P ha-l

3 Jan 10Feb 29 Apr 22 Jun 10 Aug 12 Oct

4

3

2

3 Jan 10Feb 29 Apr 22 Jun 10Aug 12Oct

3

29 Mar 11 Jun 26Jul s sep 4 Nov

Figure 2. Concentration of N, P, and K in the harvested lucerne OM as influenced by P fertilizing in the

years 1970 and 1971. 8

It must be noted that yield declined (Fig. 3) during the

hot Ju ly-August period (Table 2). Such decline is more

marked in more inland areas of the central plain, namely

Athalassa, where maximum daily temperature during

July-August exceeds 35OC, while at the same time water

consumption peaks. The combined result is that water

use efficiency drops considerably (Metochis and Orpha-

Table 4. Concentration of Mg, Zn, Mn, Cu and Fe in

lucerne dry matter harvested on 4 November

1971.

Element Concentration

Mg(%) x, KI K2

0.45

0.36

0.30

Zn(ppm) PI P2

P3

P4

29

20

19

19

Mn(ppm)

Cu(ppm)

Fe(ppm)

45

12

190

...

~ .' ..

4

3

2

1970

3Jan 10Feb 29Apr 22J un 10Aug 12 0 ct

Figure 4. Concentration of K in the harvested lucerne

1970 and 1971.

nos, 1981). This decline in yield is known as "summer

slump" (Bula and Massengale, 1972), and Metochis and

Orphanos (1981) showed that by discontinuing irrigation

dur ing July-August the crop is forced into dormancy

from which it recovers when re-irrigated in September.

In this way 40% of the irrigation water is saved at the ex­

pense of only 20% of yield.

16

..I .o

8

o o 1970 • 1971

3 1972

I

:i u 2

I o

.:;1_ "C

~ 1 >­I

x

o

o F M A M J A SON D

Figure 3. Yield of l\1cerne DM at each cut in the years

1970, 1971 and 1972 (lower), and its DM content

(upper). Means over the P rates applied.

o ~ ~ 1971 o 220 440 kg K ha-1

2

o

DM as influenced by K fertilizing in the years

r-

~ ~ ~ f%f-

~ ~ ~ l%f% /'; f%~ ~ ;;;

r-~ f% ~ ~ /:f- l% ~ ~

~ % ~ ~ ~ ~ ~v: f% l%

29Mar 11 Jun 26Jul 6Sep 4 Nov

19

ACKNOWLEDGEMENTS

, I thank Mr. G. Roushias, Mr. A. Minas, Mr. C. Hadji­

loucas and Mr. Chr. Xylaris for technical assistance, Mrs. Maria Pitri for processing the data and Mrs. Soteria Anastasiou for drawing the figures.

REFERENCES

ARI. 1967. Annual Report for 1966. Agricultural Research In­

stitute, Nicosia. pp. 59-60. •

ARI. 1968. Annual Report for 1967. Agricultural Research In­

stitute, Nicosia. pp. 59-60.

ARl. 1969. Annual Reportfor 1968. Agricultural Researche In­

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ARt 1971. Annual Reportfor 1970. Agricultural Research In­

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ARI. 1972. Annual Reportfor 1971. Agricultural Research In­

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Bula, R.I., and M.A Massengale. 1972. Environmental physi­

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Burton, J.C. 1972. Nodulation and symbiotic nitrogen-fixation.

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IIp.

10

Droushiotis, D.N. 1985. Yield and quality of new lucerne va­

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I. Soil test maintenance requirements. Soil Science Socie­

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Levin, I., A Dorrat, and G. Mozes. 1969. Yield respones of ir­

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Littlejohn, L. 1946. Some aspects of soil fertility in Cyprus.

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123-134.

Metochis, C. 1980. Irrigation ofluceme under semi-arid condi­

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Metochis, C., and P.I. Orphanos. 1981. Alfalfa yield and water

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