optimum water table depth for acra-part 5 (2)

OPTIMUM WATER TABLE DEPTH FOR ACRA:

PART 5: WATER TABLE DEPTH AND MVOL INVENTORY 2.0 YRS-R3

IN PEATLAND USING TPK 6-PAR AND REVISED PIMS’s DATA

By Dedi K. Kalsim and Dwinata Aprialdi

Workshop Nasional Kebijakan dan Tata Kelola Lahan Gambut di Indonesia, KLHK dan Wetlands International

Hotel Mirah, Bogor 27 May 2015

1 D.K. KALSIM and DWINATA APRIALDI

DRAINAGE DESIGN CRITERIA

WATER LEVEL SHOULD BE DESIGNED AS HIGH AS POSSIBLE

BUT AS LOW AS REQUIRED BY THE CROP

D.K. KALSIM and DWINATA APRIALDI 2

OBJECTIVE-METHODOLOGY • OBJECTIVE

– To study How is the relationship between MVOL and WT for ACRA

• METHODOLOGY – There are 45 compartments data of weekly WT and MVOL

2 yrs R-3

– The wt depths are classified into: • (0) wt < 0 or flooding, (1) wt 0-40 cm, (2) wt 40-70 cm, (3) wt 70-

90 cm, (4) wt 90-110 cm, and (5) wt>110 cm.

– The frequency relative of occurrence each wt class was calculated for each compartment.

– The SPSS-19 is used to analyze


RESULTS AND DISCUSSION

• The model linear is MVOL = 7.821 + 59.418 (wt>110) + 55.885 (wt90-110) + 44.737 (wt70-90) + 40.062 (wt40-70) – 152.297 (wt0-40) – 387.142 (wt<0), R2=0.482

• It means 48% of variance can be described by the model, but 52% can not be described and could be influenced by other factors than WT depth.


MVOL COMPUTED-DATA

5

y = 0.4515x + 25.245 R = 0.4709

20,00

25,00

30,00

35,00

40,00

45,00

50,00

55,00

60,00

65,00

20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00

Dat

a (m

3/h

a)

Computed (m3/ha)

MVol Data - Computed

mvol Linear (mvol)D.K. KALSIM and DWINATA APRIALDI


WT VS YIELD IN THE WORLD

Sugarcane vs WT and number of days WT<0.5 m, in Queensland, Australia (Rudd and Chardon, 1977)

Winter wheat vs average WT in heavy clay soils 5 yrs observation (FDEU, Min. Agr., UK)

Relative yields (%) of crops with different depth of WT in a muck soil (Harris et.al. 1962. Soil Science, 94 pp 158-161)

Crop Number of

years

Depth of WT (m)

0.4 0.6 0.8 1.0

Potatoes 12 46 94 97 100

Onion 11 63 109 113 100

Sweet corn 4 61 100 92 100

Carrots 4 59 93 96 100

Average 57 99 99.5 100


0

20

40

60

80

100

120

0,2 0,4 0,6 0,8 1 1,2

Re

lati

ve Y

ield

(%

)

Average WT depth (m)

Relative Yield (%) vs WT depth

YIELD (t/ha)


• Increasing frequency of wt>110 up to 0.40, will increase the MVOL from 40 to 62 m3/ha (Fig 1, R=0.354).


• Increasing frequency of wt90-110 up to 0.50, will increase the MVOL from 37 to 68 m3/ha (Fig 2, R=0.511).



• Increasing frequency of wt70-90 up to 0.60, will increase the MVOL from 37 to 52 m3/ha (Fig 3, R=0.249).



• Increasing frequency of wt40-70 up to 0.90, will decrease the MVOL from 58 to 32 m3/ha (Fig 4, R=0.464).



• Increasing frequency of wt0-40 up to 0.11, will decrease the MVOL from 50 to 28 m3/ha (Fig 5, R=0.330).



• Increasing frequency of wt<0 (flooding) up to 0.03, will decrease the MVOL from 50 to 35 m3/ha (Fig 6, R=0.446).



CONCLUSIONS • The optimum water table is 90-110 cm, MVOL 2

yr R3 ± 68 m3/ha. RAPP proposed 60-80 cm (± 52 m3/ha)

• WT 0-40 with frequency 0.11 and wt<0 (flooding) with frequency 0.03, the MVOL 2 yr R3 ± 25 m3/ha – Reduce 63% - 48%

• Increasing WT 0-40 frequency (>0.11) will be more reducing MVOL

• Flooding more than 6 weeks resulting mortality >70% (Bakung-Langgam)


optimum water table depth for acra-part 5 (2)

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