Effect of Tillage and Crop Establishment Methods On Physical Properties of a Medium-Textured Soil Under a 7-Year Rice-Wheat Rotation.

The rice-wheat (R-W) cropping system feeds 22% of the world population on less than 5% of the land area in South Asia. Current land management and crop establishment practices in the R-W system deteriorate soil health, especially soil physical properties, and are input- and energy-intensive. Conservation or zero-tillage along with drill-seeding have been promoted to overcome problems of soil health, and input and energy usages. In a 7-yr permanent plot study, we evaluated the performance of conservation tillage-based technologies on soil physical properties with an aim to improve soil health and resource-use efficiency. The rice treatments included transplanting and direct-seeding on flat and raised beds with or without tillage (puddling) followed by wheat in conventional- and zero-tilled soil. Bulk density and soil penetration resistance were higher in puddled sub-surface soils due to compaction and lower in zero-till drill-seeding conditions. Bulk density increased with depth, and was lowest (1.45 Mg m^-3) in surface soil and highest (1.78 Mg m^-3) in sub-surface soil. Similarly, soil penetration resistance was highest in puddled rice (3.58 to 3.68 MPa) and lowest in raised beds. Water-stable aggregates and mean weight diameter showed a negative time trend slope (0.97) in puddled transplanted rice. The least-limiting water range, a composite index to explain overall soil physical status, was about double in zero-till direct seeded rice?