Tillage and mulching effects on water use, root growth and yield of rainfed mustard and chickpea grown after lowland rice

Crops grown under rainfed conditions are prone to water stress, owing to rapid loss of soil moisture and development of mechanical impedance to root growth. The stress can be alleviated by enlarging rooting volume in the soil and/or by regulating the supply of soil moisture. This study reports the effects of zero, minimum and conventional tillage with and without rice straw mulch on conservation of soil moisture, root growth and yield of chickpea and mustard grown under rainfed conditions for three years (1990-91 to 1992-93) in a deep clayey soil (Typical Chromusterts). Minimum tillage, with or without straw, enhanced soil moisture conservation and moisture availability during crop growth. As a consequence, the root mass, yield components (plant stand, number of pods per plant and plant height) and grain yield increased. Availability of soil moisture during the crops growth period, maintained better plant water status. Zero tillage was superior to the other tillage practices for mustard. On the other hand, chickpea grain yield was statistically similar for zero tillage and minimum tillage. Straw mulch conserved more water in the soil profile during the early growth period compared to no mulch. Subsequent release of conserved soil water regulated proper plant water status, soil temperature, and lowered soil mechanical resistance, leading to better root growth and higher grain yield of both chickpea and mustard in straw mulch than in no mulch plots. (C) 1998 Society of Chemical Industry.