and to secure higher profitability to the farmers in the long run. Rice–wheat acreages increase substantially in Indo‐Gangetic plains (IGPs) zone due to better irrigation infrastructures and higher response to the applied inputs for long time. Also, the government support system was developed over the period to safeguards the interest of the cereal growers through better pricing, input supply, and other incentives like increased availability of quality seed of improved varieties to the farmers. Later the stockholders including the farmers realized the faults in the ongoing cereal‐based system and promoted crop diversification in originally green revolution areas.
The technological development in all sectors of crop production also promoted farmers awareness to explore for crop diversification. High yielding varieties, suited to different ecologies, were developed in oilseeds, pulse crops, and millets and improved agronomic practices. These also helped in harnessing higher productivity from the diversified cropping system. The better minimum support price of the millets, oilseeds, and pulses also help in increasing the farmers’ awareness for bringing more and more area under crop diversification. The inclusion of leguminous crop not only helps in maintaining optimum soil fertility but also helps in minimizing the impact of biotic and abiotic stresses among the crop plants due to alteration in host–pathogen relationship. It helped in maintaining over all ecological balance in agriecosystem.
The date of sowing is considered as the simplest agronomic management to minimize the impact of climate change/variability on crop growth and productivity. It will be helpful to make contingency planning to fit proper variety to extreme weather conditions like raising and decreasing temperatures, varying rainfall and other weather components. The climate smart varieties would be used in large scale on farmers' field. The diversification of cereal‐based cropping systems with the crops such as oilseed, pulse, and forage crops, is another option for minimizing biotic and abiotic stresses. The pathogenic cycles could be broken up through crop substitution (Singh et al. 2002, 2020; Rathore and Bhatt 2008). Consistent practicing of monocropping resulted in loss of soil fertility, decline of soil health, factor productivity decline and lowering crop productivity even under high productivity areas (Saha et al. 2012). Conservation tillage also promotes greater soil biodiversity thereby leading to more biotic stresse suppression. Proper pest management is a permanent challenge to the farmers, and it is a very important ecosystem service, which can be restored through crop diversification. The erosion of genetic diversity led to an increase in crop disease occurrence. Greater varietal and species richness reduce the spread of disease in agricultural systems. Habitat management in agricultural systems is an effective means to enhance natural enemies. These have been developed for effective application in crop, at farm, and few of these are reported be very economically useful for the farmers. Gurr et al. (2003). The diversity of crop species within the agro ecosystem consequently offers long‐term pest suppression by building up potential natural enemies for any pest outbreaks.
2.6 Congenial Conditions for Crop Diversification
India is a highly diversified country in terms of climatic conditions, soil types, topography, and other agro climatic conditions. Therefore, the ICAR has divided the whole country into 15 agroclimatic zones. This help for wider cultivation of number of crops in the country. India is also one of the mega biodiverse countries and many of the crops originated in India. Traditionally, the farmers were practicing a diversified cropping system by inclusion of many crops during different crop season. But over the period, after green revolution and increasing government efforts and food demand, lot of emphasis has been paid only to cereal‐based system. This resulted in growing of one or two crops only.
Diverse agro‐climatic conditions
Diverse weather within a year
Huge market
Great potential for processing and value addition
Large number of crops, including underutilized
Figure 2.3 indicated that diverse bioclimatic zones of India along with different agroclimate favors for promotion of crop diversification. For achieving a very useful diversification plan, there is a need to develop intensive cropping systems with diverse crops. Furthermore, these agro ecological regional classifications indicate very systematically the existence of diverse soil, climatic, and growing conditions and based on these diverse conditions, across the country the suitable crop diversification plans have been developed by various experts. There is a need to popularize these time‐tested crop diversification plans vigorously in the country at farmers’ fields to get all the benefits to the small and marginal farmers in particular.
2.7 Crop Diversification and Composition
It is very pertinent to suitably identify the nature of composition of crops for fool proof crop diversification plans in a specific locality. Area shifts and crop pattern changes can lead either to crop specialization or to crop diversification. Green Revolution technologies led to cereal centered specialization in large part of the country. But, later when increased productivity of food grains, especially cereals, made it possible to allocate more area to other crops such as oilseeds with a severe supply shortage, the specialization tendency witnessed earlier has given room for overall crop diversification. Crop diversification can be practiced successfully in spatial and temporal dimensions.
Figure 2.3 Agro‐ecological regions map of the country (2015) and revised Bio‐climates of India (2015) (e‐Publication: ICAR‐NBSS&LUP Technologies). (See insert for color representation of the figure.)
2.7.1 Diversification with Oilseed Crops
At present, there are around 25 Mha area under oilseed crops with 37 MT of total production, even this is not sufficient to meet domestic oil requirement, hence India is importing around 15 MT of edible oils from abroad. On the other hand, there exists enormous potential to expand oilseeds area in the country and crop diversification with oilseed crops is one of such options. And it is hugely possible in irrigated IGP regions through crop intensification, where number of computable crops are grown either in sequential or intercropping systems. There are crops which act as complementary to each other when grown together, like growing legumes with cereals, through positive allopathic effect (mustard + wheat, mustard + potato, etc.) and in tier/multistoreyed system. This type of crop combination needs to be identified and promoted for achieving desired results. The selection of crops in crop diversification depends upon many factors like available resources, prevailing weather conditions, market demand, ease of doing cultivation, and overall high productivity and profitability from the possible combinations. The established possible combination is enlisted below (Tables 2.1 and 2.2).
Inclusion of oilseed crop, Indian mustard with early maturing short duration varieties like PM 28 and PM 26 in maize (fodder)‐mustard‐late wheat system restyled n higher system productivity and also the profitability (Table 2.3). Maximum system productivity (49.9 t/ha) and system net return (Rs. 1.45 lakhs) were obtained from M‐M(PM28)‐late wheat (HD 3118) Maize‐mustard (PM28)‐late wheat (HD 3118) system.
