Efficient Nitrogen and Water Management for the Soybean–Wheat System of Madhya Pradesh, Central India, Assessed Using APSIM Model

A series of long-term simulations were carried out to investigate alternative management practices to increase grain yields of soybean and wheat by optimizing sowing dates, nitrogen (N) and water requirements, along with complimenting farmyard manure (FYM) as a N source in the soybean–wheat cropping system of Madhya Pradesh. The APSIM simulation study showed that the mean soybean yield ranged from 1.0 to 1.6 t ha−1 for the different dates of sowing. The average wheat grain yield was 3.2–3.9 t ha−1, whereas, the crop sown on 15 November gave the highest yield. In this region, there is a potential to increase soybean and wheat yields by 0.6 and 2.2 t ha−1, respectively. Among the various irrigation practices simulated, five irrigations of 60 mm at 20 days interval was the best option for wheat. Application of 16 t FYM ha−1 to soybean produced 50 % higher wheat yield than the same amount of FYM applied to wheat. The wheat yield obtained from inorganic application of N was at par with that obtained from the application of integrated and organic sources. However, the amount of N loss from the integrated use of fertilizer N was lower than that from the current recommended practice for the region. Application of FYM alone or in combination with inorganic fertilizer maintained higher soil organic carbon concentration as compared to the application of inorganic fertilizer alone. Thus, the model provided a mean of evaluating alternative crop N and water management options for effectively managing the soybean–wheat cropping system. © 2014, The National Academy of Sciences, India.