After wheat and rice, maize ranks third in the world. Maize grain has 68.5% carbohydrates, 8% fats, 4% ash, 3% crude fiber and 16.5% protein. During 2019-20 maize contributed 2.9% in value addition as well as 0.6% to GDP with the production of 7.236 million tons and 1.413 million hectares cultivated area. (Govt. of Pakistan, 2020). Being a C4 plant, Maize is depleting the soil fertility badly triggering high input requirements. There is a need to develop such a cropping system that can sustain production and soil fertility (Witt and Pasuquin, 2007).
Soybean (Glycine max L.) is considered a miracle crop because of its high protein contents (38-40% protein), edible oil (18-22% edible oil), essential amino acids, minerals and vitamins, "the meat that grows on plants."(Jiang et al., 2003). It is producing about 2/3rd of the world's protein concentration for animal and poultry feed. It is a multipurpose crop that is not only grown for its edible oil and nutrients enriched fodder but also significantly contributes to poultry feed and industrial raw material (paints, cooking, inks, biofuels, textiles, and gums). It is also used to treat chronic illnesses including cancer and heart attack (Popovic et al., 2013).
In Pakistan, soybean (Glycine max L.) was introduced in the Sindh and Punjab rain-fed regions in the 1960s. Although its commercial raising began in the 1970s yet due to its competition with major crops like maize, lack of area-specific production technology and unavailability of approved varieties, it could not get the attention of the farming community for its cultivation on large scale. In Pakistan, poor soybean germination, deterioration of its seed viability, climatic hazards and marketing problems are considered the main production constraints. The total soybean import forecast for the period 2019-2020 is 2.5 million metric tonnes. Import bills are continuously growing due to less attention paid to soybean production. National soybean production is around 689 kg/ha which is very poor in assessments with potential production, i.e. 2500 kg/ha (Govt. of Pakistan, 2019).
Crop intensification, high yielding hybrids and exhaustive conventional cropping systems of Pakistan depleting the soil badly. Cultivable land is decreasing due to urbanization and industrialization. Pakistan is still facing scarcity of edible oil. The domestic production is only 0.446 million tons while the oilseed Import bill is Rs.152.514 billion(Govt. of Pakistan, 2017). There is a wide gap between domestic production and requirements. Low oil seed status of Pakistan is due to conventional fixed cropping patterns that do not permit oilseed cultivation on a large area. There is an urgent need to develop such a type of pattern which facilitates intercropping (Khan et al., 2012). Poly-Culture, especially inter-cropping, is a beneficial approach around the world. It is beneficial for the farmer as it provides sustainable yields (Farooq et al., 2017). In Pakistan the areas where irrigated agriculture is practised and ample sunlight is available, polyculture can be an economically viable option for the small growers with respect to sustainability and productivity.
Like other options, intercropping of a leguminous crop (e.g. soybean) with maize can be a viable strategy for discoursing the above-mentioned problems. If we plan to introduce it as an intercrop with some major spring or autumn planted crop like maize, again there is a long list of issues: Being a broad leaves crop, its adjustment with narrow leaves crops like maize create problem in weeds control. Adjustment of planting geometry of maize (without disturbing maize recommended plant population) for introducing soybean as an intercrop is again a big issue. In different regions of the world, especially Chinese farmers are growing soybean very successfully with maize through bed plantation (with the help of mechanized bed planters). Sichuan Agricultural University (SAU) has a lot of its work on the 2+4 bed planting geometry of maize and soybean. But in Pakistan, most of our farmers prefer ridge sowing. So adjustment of soybean on ridges with maize again having a question mark. In Pakistan, most maize hybrids don’t have erect type leaves, so the shadding effect for soybean on later stages is very common. A maize farmer is getting 100 plus monds grain yield, so soybean adjustment as intercrop should give promising results regarding quantity and quality for the maize farmer to attract them. Specific planting geometries of maize soybean intercropping with appropriate crop manipulation can help us to overcome these drawbacks.
#intercropping
#soybean
#maize
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