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H.K. Pande and K.P. Jha
Central Rice Research Institute, Cuttack. India
Abstract
Crops and nutrition
Characterization of uplands
Fertilizers
References
One of the most important aspects of formulating a cropping system for an upland situation (whether impaled or rain-fed) is the selection of crops and varieties that are suited - with reference to their yield and quality - to the region. Foods crops needed to meet our requirements have been classified into three broad categories, e.g. energy food (cereals), body-building food (grain legumes) and regulatory food (vegetables and fruits).. Bearing in mind food habits, nutritional requirements and nutrient availability (which is much below the requirement level in the country), a scientific approach is needed for the augmentation of productivity in the uplands growing the three categories of food crops. In the absence of the possibility of increasing the cultivable area, the only way out is to increase productivity per unit of area and time. While a cropping system on irrigated uplands can be manipulated in a variety of ways, the crops and the system of cropping on rain-fed uplands afford less flexibility, in so far as they necessarily depend, primarily, on the effective utilization of the precipitation received before and during the cropping season. Climat and edaphic factors contribute significantly to the success or failure of the harvest.
Intercropping moth bean, guar bean, and mung bean with pearl millet; pigeon-pea. black gram, groundout and soybean with sorghum, has been suggested for normal rains, while intercropping mung bean and pigeon-pea with sunflower/maize/castor has been advised for aberrant weather situations (late monsoon) in and areas with a rainfall of less than 700 mm.
Collection of run-off water in storage tanks. water harvesting in situ, surface mulching, and establishment of optimum plant population through seeding at optimum depth of soil at appropriate sowing time are the proven technologies for successful cropping in and areas. Application of farmyard manure on seed furrows to avoid crust formation and reduce seeding mortality, along with increasing moisture-holding capacity, should provide invaluable aids in crop establishment. In such areas, even in favourable and normal years, sequence-cropping is advisable, e.g. pearl millet/sorghum (for fodder), or pearl millet and cow-pea (for fodder), followed by mustard. Alternatively, short duration varieties of black gram or mung bean, followed by chick-pea/mustard/raya/safflower. The cropping strategy for moderate rainfall areas (700-1,100 mm rain) may be intercropping systems such as maize and green gram/soybean; cotton and green gram /for the north and north-western region); groundnut + red gram, cotton + green gram (for the central region) and groundnut/finger millet + red gram (for the southern region) and a sequence-cropping system, such as maize/early rice followed by chick-pea (for north and north-western region); pearl millet/sorghum followed by chick-pea or black gram followed by wheat or green gram followed by sorghum (for central region); sorghum-cow-pea, green gram - sorghum/sunflower (for southern region).
Areas with rainfall more than 1,100 mm should adopt intercropping of pigeon-pea, groundnut, mung bean, soybean in main crops of maize/sorghum/early rice. Proper crop geometry between intercrop and main crop has to be worked out on a regional basis. For the eastern region, two or three rows of rice alternated with one row of mung bean or three to four rows of rice with one row of pigeon-pea, have been optimum. Intercropping legumes in cereals have shown increased yield of grain as well as protein and lysine. In soils retaining adequate moisture and nutrients, double cropping systems like maize-toria/wheat, rice-chick-pea and soybean-wheat, have been suggested.
It has been observed that suitable crop combination increases productivity not only in quantity but in nutritive quality as well. It has been reported that mixing whole wheat meal with green gram (mung bean) in the proportion of 90:10, increased the chemical score of protein in the combined diet to 71 per cent, as against 53 and 47 per cent for wheat and green gram alone. Cereals, like wheat and barley. in combination with other pulses, like cow-pea, lentil, red gram, pea. and chick-pea, have given similar results.
Cropping systems are dependent on their physical and socio-economic environment. The productive base of any cropping system is plant growth, which is influenced by environment and management. The environment includes physical factors related to climate (rainfall, temperature, and solar radiation), land (soil types, location, and topography) and socio-economic resources specific to costs, like the availability of production inputs, product prices, marketing facilities, and preferences for certain food and management practices. Overall, the cropping pattern performance is the continuous function of available resources.
Cropping system design employs certain criteria, like the yield of the component crops within the pattern, which should be economically viable and biologically stable. The economic resource requirement of the system should be such that the input of labour, power, seed, fertilizer, and plant protection can be met in time, adequately, and economically. Physical variables, such as rainfall, temperature and soil types, influence the system classification and define the ecological zones. An ecological zone is one across which a relatively uniform potential of crop growth is a common phenomenon. It would not amount to an oversimplification to consider the cropping system design approach as one that involves the matching and linking of the environmental conditions for crop growth with the management requirement of the crops in combinations that bring about their best potential. To design each cropping system, it would be necessary to identify environmental, physical, socio-economic, and biological variables that relate to crop growth and management. However, the determination of crop requirement and the classification of environmental parameters may not always be very precise, and the design may be developed on the basis of probabilities. Cropping system design is not a mechanical or automatic process; it must be developed from an understanding that agricultural practices, that are to be evolved and adopted successfully across an ecological zone, are an evolutionary process, in which a minor adjustment of the system should provide the prospect of exploiting any potential to the optimum.
Out of the 140 million hectares of total cultivated area in the country, about 25 per cent is irrigated. Except for the area under lowland rice, the remaining cultivated land may be categorized as under upland management - little is medium land. Such crops are grown on the soil moisture received from rainfall, the system is known as rain-fed farming. For successful adoption of crops and cropping system, the primary consideration is that the conserved soil moisture is a limiting factor.
Since there is little more land to be brought under cultivation, the increasing demand for food in the country must be met through increased productivity of the existing land per unit area and per unit time. The productivity of rain-red uplands being low, judicious crop planning with scientific management aimed at exploiting resources to the maximum, would be the primary approach. The production objective would be not only the quantity but also the quality of the produce specific to the nutritional needs of the people.
Crops meeting the nutritional needs can be categorized. Energy-rich foods include cereals (rice, wheat, barley, millets), pulses, sugar, and oilseeds. Body-building foods are crops like grain legumes, rich in proteins.
Regulating foods are fruit and vegetable crops. Other sources of nutrients, such as cattle, poultry, and aquaculture. though significant, are beyond the scope of this paper.
Data recorded for 1978 appear to show that the per capita consumption of pulses was only 45 g per day, while the total area covered by pulses was 23.5 million hectares providing 12.1 million tonnes of legume grain. WHO/FAO has recommended consumption of 104 g pulses per capita per day. Based on a more modest estimate of 60 g, our pulse needs would come to about 24 million tonnes. Thus, the productivity of pulses has to be doubled, and this is attainable by following a cropping system on the uplands with cereals and legumes in sequence or intercropped. Successful practice of intercropping has opened new vistas for rain-fed uplands where soil moisture is the usual constraint.
A combination of cereals and pulses in the Indian diet has a complementary relationship in meeting the essential amino acid needs both of lysine and the sulphur-containing amino acids, like methionine. Mixing whole wheat meal with green gram (mung bean) in the proportion of 90:10 increased the chemical score of protein in the combined diet to 71 per cent, against 53 and 47 per cent for wheat and green gram alone. Cereals like wheat and barley in combination with pulses, like cow-pea, lentil, red gram, pea and chick-pea, give similar results. Combinations of cereals and pulses give a chemical score for proteins which compares favourably with those of animal protein (Jain 1980).
The choice of crop and the cropping system for rain-fed uplands depend, in the main, on effective utilization of the precipitation received during and before crop cultivation. Management of these lands has been developed with the prospect of utilizing the entire rainfall received on the land. The areas receiving varying amounts of precipitation have been classified into three categories: areas of low rainfall (below 700 mm), medium rainfall (700-1,100 mm), and high rainfall (above 1,100 mm). Both the amount of precipitation and management decide the mono-, inter- or double-crop systems to be followed. Besides these, other relevant climatic factors are temperature, sunshine, and humidity, besides soil types and soil condition. Thus, the whole system is location-specific. Socio-economic considerations, like cost, availability of production inputs, marketability and consumers' preferences for the produce, influence the crop-growing decisions within the cropping system.