Rice–Wheat Cropping Systems

Abstract

Publisher Summary According to the International Food Policy Research Institute, between 1993 and 2020 A.D. the global demand for cereals is expected to increase by 41%. It has been projected that annual rice production must increase from 556 million tons in 2000 A.D. to 758 million tons by 2020 A.D., a 36% increase. Rice-wheat cropping system (RWCS) is a long-established grain production system in China. The wheat yield following rice was only 0.7 to 1.0 tons ha-1 until the 1940s and it increased progressively after the 1950s as a result of improved varieties, better agronomic management, and pest control. RWCS in the Indian subcontinent is quite new and started only in the late 1960s with the introduction of dwarf wheat from CIMMYT, Mexico, which required a lower temperature for good germination than that required for traditional tall Indian wheat. There could be many more variants involving vegetables and other short duration crops. Most rice in RWCS is transplanted and rice varieties grown are of 90–140 days duration (seed to seed) of which 25–45 days may be spent in nursery. The estimates of area under RWCS in the world vary considerably. In RWCS there is very little turn-around time between rice harvest and wheat sowing. Depending on the time of harvest of the rice crop, conventional tillage requires pre-sowing irrigation on well-drained soils or draining or drying of soil in lowlands followed by one or two diskings, two harrowings, and leveling. Wheat in the RWCS belt in Indo-Gangetic Plains (IGP) is an irrigated crop. Considerable research has been conducted in India on the irrigation of wheat. Currently, there is a growing concern in sustainability of RWCS as the growth rates of rice and wheat yields are either stagnant or declining. Studies on socioeconomic and policy factors on the productivity of RWCS will be effective for measuring outcome of RWCS.