The classification of crops based on agronomic practices
The classification of crops based on agronomic practices is given below:
i. Catch crop/emergency crop/contingent crop: The crop that is cultivated to catch the forthcoming season. It replaces a main crop that has failed due to biotic or climatic or management hazards and thereafter, utilizes the remaining period of the season. It provides livestock feed at a difficult time of year, check weed growth, conserve soil, and utilize added fertilizer and moisture. Such crop is generally of very short duration, quick growing, fast bulking, harvestable or usable at any time of their field duration and adaptable to the season, soil and cultural practices, for instance green gram, black gram, cowpea, spinach, radish, coriander, onion etc.
ii. Restorative crop:The crop which provides a good harvest along with enrichment or restoration or amelioration of the soil, such as legume. It fixes atmospheric nitrogen in root nodules, shed their leaves during ripening and thus restore soil conditions.
iii. Exhaustive crop:The crop plant which on growing leaves the field exhausted because of a more aggressive nature, for instance sesame, brinjal and linseed.
iv. Relay crop:In multiple cropping, the crop plant which is sown a few days or weeks before the harvesting of the standing mature crop. The crop is grown on residual moisture without preparatory tillage. For instance black gram in aus paddy, grass pea in anzan paddy, sweet guard in potato.
v. Smother crop:The crop plant which is able to smother or suppress the population and growth of weeds by providing suffocation curtailing movement of air) and obscuration (of the incidental radiation) by its dense foliage developed due to quick growing ability with heavy tillering or branching, planophyllic or procumbent or trailing habits, for instance barley, mustard, cow-pea, sweet gourd.
vi. Cover crop:The crop plant which is able to protect the soil surface from erosion (wind, water or both) through its ground covering foliage and/or root mats: for instance groundnut, marvel grass, black gram, rice bean, grass pea, sweet potato, para grass.
vii. Nurse crop:The crop plant which helps in the nourishment of other crops by providing shade and acting as climbing sticks such as Jowar in cow-pea. Leguminous or deciduous plants shed their leaves and thus enrich the surface soil for better growth of the crops grown underneath. Shade loving plants (sciophytes) such as turmeric, ginger and corm are nourished by tall crops such as pigeon pea, castor, and climbing vegetables such as cucumber, ash gourd and bean.
viii. Guard or barrier crop: The crop plant which helps to protect another crop from trespassing or restrict the speed of wind and thus crop damage such as safflower in gram.
ix. Brake crop:The crop which is grown to break the continuity of the agro-ecological situation of the field under multiple cropping system. The inclusion of such crop in the cropping system helps to reduce the inoculum of soil-borne harmful biotic agents such as weeds, pests, pathogens and parasites and improves soil conditions for crop growth. Growing potato, pulses or oil seeds in continuous cereal cropping systems, for instance rice-rice, rice-wheat, rice-maize breaks the continuity of a large number of pests due to variations in host ranges and changing of agro-ecological situations. Brake crop is also used to designate guard crop particularly the one which helps to brake the wind speed and protect other crop plants from wind hazards.
x. Trap crop: The crop plant which is grown to trap soil borne harmful biotic agents such as parasitic weeds, Orobanche and Striga that are trapped by Solanaceous and sorghum crops, respectively. These weed seeds germinate when they come in contact with roots of these crop plants. Thereafter the destruction of these crops reduces the inoculum of such parasitic weeds. Similarly, nematodes are trapped by some Solanaceous crops. On uprooting crop plants, nematodes are pulled out from the field soil.
xi. Mulch crop:The crop plant which is grown to conserve soil moisture from bare ground by its thick and multilayered foliage, trailing habit and sometimes, self-seeding nature, for instance cowpea.
xii. Sod or turf crop: The crop plant that belongs to the grass family and has sod type tillers with matted foliage and roots close to the soil surface is grown to conserve soil from erosion particularly in non-arable areas, for instance marvel grass, Digtlaria sanguinalis, Cynodon dactylon.
xiii. Cleaning crop:The crop plant whose agronomic practices makes the field clean from weeds and stubble, for instance potato, groundnut, ginger, turmeric, and colocasia which require considerable earthwork such as earthing up, preparation of irrigation and drainage channels, placement of top-dressed fertilizers and harvesting by digging which helps to disturb the soil surface, the site of weed growth.
xiv. Fouling crop:The crop plant whose cultural practices allow the infestation of weeds intensively, for instance maize, cotton and direct seeded upland rice as they have low coverage over the ground at their earlier stages of growth and wider spacing and slow growth at the beginning.
xv. Cash crop:The crop plant which is grown for sale to earn hard cash. The processing of such a crop after harvest is beyond the means of individual farmers, for instance jute, tobacco, cotton and sugar cane.
xvi. Silage crop:The crop plant which is grown to preserve in pits (silo pits) in a succulent condition by a process of natural fermentation or acidification for feeding livestock during lean months or off seasons: for instance maize, cowpea, jowar, bajra, and berseem.
xvii. Soiling crop: The crop plant that is grown to harvest while it is still green and fed fresh to livestock in stalls, for instance berseem, oats, cow-pea, napier, rice and bean.
xviii. Green manuring crop: The crop plant which is grown to be incorporated into the soil fresh to increase the fertility of the soil. Green manuring may be green leaf manuring or green manuring in situ, such as dhaincha, sunnhernp, Glyricidia.
xix. Mixed crop:Two or more crops that are grown simultaneously in the same field without preserving their identity with respect to field area. Seeds of these crops may be mixed together before sowing and broadcasted irregularly or drilled in rows or may be sown at the same time and grown with the same management practices. They may be harvested together or separately, for instance: wheat+mustard, gram+safflower, maize+cow pea, jowar+cow pea, linseed+mustard, berseem+mustard.
xx. Intercrop:Two or more crops that are grown simultaneously in alternate rows in the same field. Such crops are not necessarily sown at exactly the same time and their harvest times may be quite different but they are usually simultaneous for a significant part of their growing periods. These crops are grown with the same agronomic practices without separate identities except for the respective rows. Here there is one main crop while the others are subsidiary crops, for instance sesame-i black gram, pigeon pea+groundnut, sorghum+pigeoil wheat+mustard, rice+pigeon pea, berseem+ mustard.
xxi. Companion crop: In intercropping, when subsidiary crops are usually of a shorter duration in a long duration main crop i.e. the main crop gets the company of a short duration crop for a certain period at the early stages of its growth, for instance potato, onion and spinach in autumn planted sugar cane, lady’s finger and amaranths in spring planted sugar-cane; radish in potato; cow-pea, rice bean, green gram in napier.
xxii. Parallel crop:Two or more crops which are grown simultaneously but do not have inter-competitive effects i.e., they are parallel with respect to competition, for instance maize+cow pea, sorghum+pigeon pea.
xxiii. Ratoon crop or stubble crop or coppice or providence or regenerated or second or third-cycle crop: In perennial or multicut crop plants it refers to the subsequent harvests taken from the regrowth of the root stocks, stubble and stumps, after the first harvest such as for sugar cane, rapier, berseem, rice, jowar, bajra, oats, Guinea grass and rice bean. Such crops reduce the cost of cultivation, do not need seed and sowing, reduce the crop cycle period, produce a higher yield per unit time and often require less input.
xxiv. Seed crop: The crop plant which is grown for seed production (generative yield), for instance the seed crop of jute, cabbage, cauliflower; potato, tobacco, oats, berseem, cowpea and maize. Such crops require special care and management to maintain the satisfactory genetic identity and purity of the crop variety (agro-ecotype) and a healthy crop.
xxv. Leaf crop:The crop plant which is grown to harvest leaves for economic yield, for instance tobacco.
xxvi. Fuel crop:The crop plant which is grown to obtain fire wood or solid fuel as a byproduct along with its economic yield, for instance jute, sugar cane, pigeon pea, cotton, mustard and sesame.
xxvii. Energy crop:The crop plant which is grown to obtain liquid energy such as ethanol and alcohol, for instance sugarcane, potato, maize etc. which are used for fermentation and distillation.
xxviii. Contour crop:The crop plant which is grown on or along the contour lines to protect the land from erosion, for instance, marvel grass and Setaria.
xxix. Augmenting crop: When subcrops are sown to supplement the yield of the main crops; the subcrops are known as augmenting crop, for instance mustard with berseem, Chinese cabbage with mustard. Here the mustard or cabbage helps in getting a higher yield of fodder in spite of the fact that berseern gives a poor yield in the first cutting.
xxx. Alley crop:When arable crops are grown in alleys formed by trees or shrubs, established mainly to hasten soil fertility restoration, enhance soil productivity and reduce soil erosion they are known as alleycrops. Such crops should have slight shade tolerance and should be non-trailing, for instance sweet potato, black grant, turmeric and ginger in between the rows of Eucalyptus.