Soil Physical Effects of Puddling in Rice–Wheat Cropping Systems

Rice-wheat is the principal cropping system in Asian countries, covering about 24 million ha area. Puddling (wet tillage) is the most common technique of rice establishment in this system. However, controversies exist regarding the residual effects of puddling on wheat yield cultivated after rice. The reasons for these are that puddling effects on soil properties are texture related, and cultivation is done under variable conditions of climate and management. Post-rice wheat yields are generally low in those soils that undergo radical changes in their physical properties upon puddling. This chapter briefly reviews the effects of puddling on soil physical properties, and their influence on rice and wheat productivity. Wheat yields in post-rice soils may be constrained due to factors such as large turnaround time, poor soil tilth of seedbed, subsoil compaction, poor drainage, restricted aeration, and high mechanical impedance to roots. Adoption of a tillage system less intensive than puddling in rice may benefit the subsequent wheat crop. Organic residue management to enhance recovery of soil structure in post-rice soils, breaking hardpans by deep tillage, subsoiling or chiseling, or optimally regulating nutrients and water in the soil layer above the compact zone are other options to improve wheat yields in post-rice soils. In coarse-textured soils, as in the Indo-Gangetic plains, alternate tillage systems, including bed planting, zero or conservation tillage, and others, seem to have good potential and may be critically examined and adopted to reduce cost of cultivation and sustaining rice-wheat productivity.