Impact of tillage and residue management on dryland spring wheat development

Abstract

No-till or reduced tillage practices are frequently recommended to reduce wind and water erosion and to increase soil water storage. Grazing stubble after harvest or producing crops with low residue may negate the benefits of the tillage practices. In this study, we determined the effects of tillage and residue management systems on the growth and development of the subsequent spring wheat ( Triticum aestivum L.) crop. The study was conducted for 2 consecutive years in eastern Washington, USA. The soil was a (Chard) silt loam. Tillage treatments were conventional (spring sweep and summer cultivation) and no-till (chemical fallow). Residue management treatments were: (1) all crop residues removed at the beginning of the 21-month fallow period; (2) all surface residues removed after the first winter rainy season; (3) no residues removed. For the 1988 crop year, 3.0 Mg ha −1 of winter wheat residue and for the 1989 crop year 0.7 Mg ha −1 of barley ( Hordeum vulgare L.) residue was present at the beginning of the fallow period. Growing season precipitation was 153 mm in 1988 and 91 mm in 1989. Water use efficiency and grain yields were generally higher in 1989 than in 1988. No differential germination or emergence stresses owing to treatments were found in either year. In 1988, stored water at the time of planting was lower where surface residues had been removed than where they had not been removed and, by anthesis, plants in the residue removal treatments began to show signs of water stress. Relative water content of flag leaves of these plants was lower than when residue was not removed and the plants also lost more tillers. At maturity, the reduced number of heads m −2 and seeds per head led to a reduction in final grain yield of about 0.5 Mg ha −1. In 1989, a better crop year, no significant treatment differences were observed at any stage of development. These results illustrate the importance of proper residue management, especially in moisture limiting environments.