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3-4

ตารางที่ 3-1 ระดับความตองการปจจัยตอการเจริญเติบโตของขาวนาปรัง

LAND-USE REQUIREMENT FACTOR RATING
LAND QUALITY Diagnostic factor Unit S1 S2 S3 N
TEMPERATURE(t) Mean temp. in growing c 22-30 31-33 34-35 >35
period 21-20 19-18 <18
MOISTURE AVAILABILTY (m) Ann. Rainfall
Water requirement in mm. 700-800 550-700 400-550 <400
growing period
OXYGEN AVAILABILITY(o) Soil drainage class 1,2,3 4 5 6
NUTRIENT AVAILABILITY(s) N (total) %
P ppm.
K ppm.
Organic matter %
Nutrient status class VH,H,M L VL
NUTRIENT RETENTION(n) C.E.C. ดินลาง meq/100g >15 3-15 <3
B.S. ดินลาง % >35 <35
ROOTING CONDITIONS(r) Effective soil depth cm. >50 25-50 15-25 <15
Gravel % <5 5-15 15-40 >40
Root penetration class 1,2 3 4
FLOOD HAZARD(f) Frequency yrs./time 10yrs/1 5-9yrs/1 3-5yrs/1 1-2yrs/1
EXCESS OF SALTS(x) EC. Of saturation mmho/cm <2 2-5 5-10 >10
SOIL TOXICITIES(z) Depth of jarosite cm. >150 100-150 50-100 <50
Reaction pH 5.6-7.3 7.4-7.8 7.8-8.4 >8.4
ในสภาวะน้ําแชขัง 5.1-5.5 4.0-5.0 <4.0
SOIL WORKABILITY(k) Workability class class 1,2 3 4
POTENTIAL FOR Slope class A B C >C
MECHANIZATION(w) Rockout crop class 1 2 3 4
Stoniness class 1 2 3 4
EROSION HAZARD(e) Slope class A B C >C
Soil loss Ton/rai/yrs

Note :- Day length - short day/day neutral
Growing period - 110-120 day
Critical period (moisture) - Booting to flowering
Soil texture requirement of crops - sc, sic, c
Others – Heavy soils with impervious layer below the plow sole is best sated to lowland rice.
S 1 : Highly suitable
S 2 : Moderately suitable
S 3 : Marginally suitable
N : Not suitable