Contingent crop planning for aberrant weather
conditions
10.1 Effect of aberrant weather conditions on crops
Rainfall behaviour in dry farming areas is erratic and uncertain. The
deviations in rainfall behaviour commonly met with in dry areas include delayed
onset, early withdrawal and intermediary dry spells during rainy season. The
adverse effect of these rainfall aberrations on crop growth vary with the degree of
deviation and the crop growth stage at which such deviations occur (Table 10.1).
Suitable manipulations in crop management practices are needed to minimize such
adverse effects of abnormal rainfall behaviour. These management decision,
constitute contingency planning. Such management practices done after crop
establishment and in the middle of crop growth are called mid season or mid term
corrections.
Table 10.1 Effect of rainfall aberrations on crops
Rainfall aberration Effect on crops
Delay in onset of rainfall Length of cropping season or cropping
duration is reduced – crop sowing is delayed
Early withdrawal or cessation of
rainfall
Moisture stress at maturity grain filling is
affected (terminal stress)
Intermediate dry spells
a. Immediately after sowing Germination will be affected, plant population
will be reduced
b. At vegetative phase Affects stem elongation, leaf area expansion,
branching or tillering
c. At flowering Affects anthesis and pollination, grain / pod
number is reduced
d. At ripening Grain filling and grain size reduced
10.2 Contingency cropping
Contingency cropping is growing of a suitable crop in place of normally sown
highly profitable crop of the region due to aberrant weather conditions. In dryland
agriculture, contingency of growing another crop in place of normally grown crop
arises due to delay in the onset of monsoon. Depending upon the date of receipt of
rainfall, crops are selected. It is assumed that the rainfall for the subsequent period is
normal and depending upon the economic status of the farmer, certain amount of
risk is taken to get good profits if season is normal or better than normal.
Contingency cropping is highly location specific due to variation in amount
and distribution of rainfall. Especially in arid regions, the spatial distribution of
rainfall is highly variable. It is common to observe that rainfall received varies from
field to field in the same location. Temperature gradually falls from August onwards
reaching minimum in November and December. Contingency plan and midterm
corrections vary with the type and time of occurrence of rainfall aberration (Table
10.2).
Table 10.2 Contingency crop plan for different abnormalities
Rainfall abnormality Contingency plan and midterm correction
1. Delayed onset of rainfall
a) Delay exceeding-4 weeks Alternate crops of short duration to be sown
Delay in South west monsoon
Normal – June
Delay – July
Delay – August
Groundnut
Ragi / pearl millet
Sama ( little millet) / Cowpea
Delay in North east monsoon
Normal – October
Delay – Early November
Delay – Late November
Cotton / Sorghum
Sunflower / Pearl millet / Ragi
Coriander / Bengalgram
b) Delay of 1 to 2 weeks Alternate varieties of short duration of same crop
Eg. Sorghum Co 19 (150 days) Co 25 (110 days),
Red gram local (180 days) Co 5 (130 days)
2. Early withdrawal of rainfall Antitranspirant spray, harvesting for fodder
(millets), harvesting at physiological maturity
3. Intermediary dry spell
a. Immediately after sowing Gap filling with subsequent rains if stand
reduction is less than 20%. Re-sowing if stand
reduction is more than 20%, mulching between
crop rows. Stirring soil surface to create dust
mulch to reduce evaporation
b. At vegetative phase Mulching,antitranspirant spray, spraying
potassium chloride, thinning of 33-50 %
population
c. At flowering Antitranspirant spray, harvesting for fodder
and ratooning with subsequent rains in millets
(e.g sorghum)
d. At ripening Antitranspirant spray, harvesting for fodder,
harvesting at physiological maturity
Crops have to be selected with suitable crop duration to coincide with the
length of the growing season. Generally short duration pulses like greengram,
blackgram and cowpea may suit the situation. However if the monsoon turns to be
extraordinarily good, opportunity is lost if only short duration crops are sown.
Farmers with economic strength and motivation for high profits with some amount
of risk can go for crops of long duration. The long duration crops with flexibility or
elasticity in yield are more suitable. For example, pearlmillet, and sorghum can be
ratooned if monsoon extends. Sunflower can be introduced for higher profits with
certain amount of risk. Crops like sorghum, pearlmillet, can be grown for grain if
monsoon extends and if not, fodder can be obtained.
Contingency crops for different situations and regions of Andhra Pradesh and
other states are suggested in Tables 10.3 and 10.4.
Table 10.3 Suggested contingency cropping for different situations in Andhra
Pradesh
Time of onset
of sowing rains Crop Varieties Regions/situation
May Sesamum Madhavi, Gowri Medium black soils,
medium and deep red soils
June Sorghum CSH-5, CSH-9, CSH-10, CSH-11, CSV-1.1,
CSV-12, SPV-462, SPV-475
Red soils, light black soils.
Castor Kranthi, Haritha Telengana region
July Groundnut TMV. 2, Tirupati-1, Vemana, Scarce rainfall zone of A.P.
August Cotton Mahanandi, NHH-4, Jayadhar, MCU-5
Groundnut TMV-2, First fortnight of August,
Arid
Regions of Anantapur
Pearl millet ICTP 8203 WCC-75 Red soils.
Sunflower MFSH-1, MFSH-8, MFSH-17, APSH-1L Red soils and black soils
Setaria Lepakshi, Prasad, Srilakshmi Black soils, deep red soils
September Sunflower MFSH-1, MFSH-8, MFSH-17, Black soils .
APSH-1J, Adarsha
Redgram LRG-30, LRG-41 Red soils in regions
receiving North- East
Monsoon rainfall
Sorghum NTJ-1, NTJ-2, M-35-1, CSH-5 Red and Black soils
Tobacco Natu special, Sun cured natu Black soils, deep red soils
October Sorghum M-35-1, CSH-7R, CSH-6R, CSH-13R, NTJ1, NTJ-2, N-13, N-14
Black soils
Coriander CS-4, CS-6 Black soils
Sunflower Any hybrid Black soils
November Sorghum Rabi varieties Black soils
Bengal gram Annegiri, ICCV-2 (Swetha), ICCV37(Kranthi), JG-11
Black soils
Safflower Manjira, Sagar muthyalu Black soils
Coriander CS-6 Black soils
Table 10.4 Contingent crops for dryland regions of India
Onset of sowing rain Crop Varieties
Dantiwada region of Gujarat
July 15 Pearl millet GHB 32, GHB 39
Sorghum CSH 5, CSH 6
Castor GAUCH-1, CAUCH-4
July 25 Sorghum CSH-6, GJ-35
Castor GAUCH-1, GAUCH-4
Clusterbean Malosan, HG 75..
August 15 Castor GAUCH-1, GAUCH-4
Sorghum (fodder) Malavan, S-1049
Pearl millet (fodder)
August 31 Sorghum (fodder)
Sesamum Purva-1
Pearl millet (fodder)
September 15 Sorghum (fodder)
Sesamum
Maize (fodder)
Hissar region of Haryana
Upto July 20 Pearl millet HHB-50, HHB-45
August 15 Cluster bean FS-227
October 15 Bengal gram G-24, C-214
October 30 Mustard RH-30
Jodhpur region of Rajasthan
July 20 Pearl millet
Greengram
After July 20 Greengram