Synthesis of Systems Diagnosis

Summary Rice-wheat systems in the Indo-Gangetic Plains may seem simple, but in reality they are enormously complex, with numerous productivity and sustainability problems, each embedded in a web of interactions. By unraveling and understanding these interactions, and harnessing their power, scientists working with the Rice-Wheat Consortium for the Indo-Gangetic Plains are fostering sustainable improvements in system productivity. Rice-wheat system problems include late sowing, low water and nutrient use efficiency, groundwater depletion (in some areas) or waterlogging and poor water control (in other areas), salinity and sodicity (in defined locales) and the build-up of problem weeds and possibly of pests and diseases. The low soil fertility scenario is due to the increasing micronutrient deficiencies, widening NPK ratios or imbalanced fertilizer use, and decreased use of organic sources of nutrients. At first glance, these problems seem random and unrelated but in fact, many of them are closely linked through system interactions. Late sowing, for example, reduces water and nutrient use efficiency, and restricts the time available within the rotation for break crops, thereby contributing to the build-up of problem weeds and to soil fertility decline. Reduced and zero tillage for rice and wheat improve timeliness of sowing and, through these same system interactions, help farmers cope with multiple productivity and sustainability problems.