Cropping System Under Low Land/ Irrigated Upland/ Rain Fed Up Lands. Multiple cropped lands can be broadly grouped into low lands, irrigated uplands and rain fed uplands.
1) Low Lands: Rice based cropping systems predominate in low lands, number of crops per year and the crops that follow or precede rice depends on the periods of water availability and degree of control of water.
When irrigation or rainfall > 200 mm/ month extends over 9 to 10 months. The system as rice- rice –rice and rice-rice-upland crop when this period limited ( 6 to 8 months) crops as upland crop-rice-uplands crops maybe appropriate, if water is available for 4-5 months, only rice crop is grown.
2) Irrigated up Lands: In irrigated up lands where winter is mild, upland crops that can follow rice include legumes as green gram, black gram, soybean, groundnut, cereals as maize, sorghum, pearl millet and other crops are cotton, sunflower, vegetable. Where winter is cool, and then rice, wheat, barley, mustard, chickpea and potato. On irrigated high rainfall uplands sequential cropping with wide range of crops is possible then system as cereal- cereal and cereal – legume, oilseeds or other cash crops. In northern India, potato or mustard can be added to maize- wheat by relay planting either of these in the standing maize and delaying wheat by about 2 months short duration green gram or fodder crops can be grown after the harvest of wheat of wheat in summer.
3) Rain Fed up Lands: Cropping system in rained uplands predominantly takes form of intercropping during rainy season. Cereal + pigeanpea, Set aria + cotton, are popular in India. Vertisols put up fallow in rainy for moisture retention found followed by sorghum, chickpea, sunflower or coriander, double cropping can be practiced when monsoon is relatively early cereal/Pulses, safflower/gram.