CRITERIA TO SELECT CROPS IN SEQUENCE FOR ROTATIONAL CROPPING
Non –leguminous crops should be followed by leguminous crops and vice-versa, eg. green gram – wheat / maize. If preceding crops are legume or non-legume grown as intercrops or mixed crops, the succeeding crop may be legume or non legume or both.
Restorative crops should be followed by exhaustive or non-restorative crops.eg. seasame – cowpea / green gram / blackgram / groundnut.
Leaf shedding crop should be followed by non-leaf shedding or less exhaustive crops.eg. pulses / cotton – wheat / rice.
Green manuring crop should be followed by grain crops.eg. dhaincha - rice, green gram/ cowpea – wheat / maize.
Highly fertilized crops should be followed by non-fertilised crop.eg. maize - black gram/gourds.
Perennial or long duration crops should be followed by seasonal /restorative crops. eg. napier / sugarcane - groundnut /cowpea /green gram.
Fodder crops should be followed by field or vegetable crops. eg. maize + cowpea-wheat/potato/cabbage/onion.
Multicut crops should be succeeded by the seed crops. eg. green gram/maize.
Ratoon crops should be followed by deep rooted restorative crops. eg. sugarcane/jowar-pigeonpea/Lucerne/cowpea.
Fouling crops should be followed by cleaning crops.eg. jowar /maize potato/ groundnut.
Cleaning crops should be followed by nursery crops. eg. potato/ colocasia/ turmeric / beet/ carrot-rice nursery/ onion nursery/ tobacco nursery/ vegetable nursery.
Deep rooted crops should be succeeded by shallow rooted crops. eg. cotton/ castor/ pigeonpea – potato / lentil /green gram etc.
Deep tillage crops should be followed by zero or minimal tillage crops. eg. potato / radish / sweet potato/sugarcane - black gram/green gram/green manuring crops.
Dicot crops should be followed by monocot crops. eg, potato / mustard / groundnut / pulses – rice / wheat / sugarcane / jowar or dicot + Monocot crops should be followed by dicot + monocot or either dicot or monocot crops.
Stiff stubble leaving crops should be followed by minimum intercultivation requiring crops. eg. sugarcane / sorghum/cotton /pigeonpea- fodder crops.
The crops of wet (anaerobic) soil should be followed by the crops of dry (aerobic). eg. rice-Bengal gram/Lathyrus/pulses/oilseeds. The tendency to buildup difficult-to-control weeds becomes less in such rotation than in continuous wet land rice culture.
The crops that are susceptible to soil-borne pests and pathogens should be followed by tolerant / break / trap crops. eg. sugarcane-marigold for pathogenic nematodes, tomato / brinjal / tobacco / potato-rice / pulses for Orobanche, jowar-castor for Striga and berseem-oats for Cuscuta.
The crops with problematic weeds (weeds that are difficult to distinguish at any one stage of crop, may be seedling or seed stage) should be followed by cleaning crops / multicut crops / other dissimilar crops or varieties. eg. wheat-wet rice for Phalaris minor, berseem-potato / boro rice for Cichorium intybus, mustard early potato for Cleome viscose, rice-jute /sugarcane / vegetable/ maize + cowpea for Echinochloa crusgalli, jute- multicut fooder / vegetable or Corchorus acutangulus.
Pasture crops should be followed by fodder or seed crop. eg. para grass – maize + cowpea / cowpea / rice bean / tetrakalai for seed.
Silage / hay / cleaning crops should be followed by seed crops. eg. maize / groundnut - onion, cowpea / jowar for seed crops.
Crops with the same symbiotic / associated microbes should be followed by common host crops, such as,
Rhizobium melilote - lucerna, sweet clover, fenugreek
R. trifolli - berseem, Persian clover
R. leguminosorum - peas, lentil, Lathyrus
R. phaseoli - beans, green gram, pillipesara, black gram
R. lupine - Lupines
R. japonicum - cowpea, pigeonpea, guar, sunhemp, Bengal gram, soybean, kudzu
The rotational use of crop varieties, and cultural practices in addition to rotational cropping provides more and assured benefits than that of adopting only crops or land rotation.