Response of Spring Barley to Crop Rotation, Conservation Tillage, and Weed Management Intensity

Abstract

AbstractConstraints to the adoption of conservation tillage in central and eastern Quebec potentially include cool wet springs, short growing seasons, and variable precipitation patterns. This study was conducted to determine the suitability of conservation tillage practices to cereal cropping systems in this area of Quebec. The effects of crop rotation [spring barley (Hordeum vulgare L.) monoculture; spring barley‐red clover (Trifolium pratense L.) rotation], tillage [fall moldboard plow (MP); fall chisel plow (CP), and direct‐seeded no‐till (NT)], and weed management intensity (intensive, moderate, minimum) on populations and dry weights of crop and weeds at midseason, and on grain yields and yield components were examined on a Kamouraska clay and a Saint‐André gravelly‐sandy loam. On the clay site, moderate weed management in NT treatments resulted in crop establishment, growth, and yields comparable to those in MP treatments. Over five years, grain yields in NT treatments averaged 2877 kg ha−1, compared with 2870 and 2260 kg ha−1 in MP and CP, respectively. Grain yields were also consistently but not statistically higher in the rotation (3014 kg ha−1) than in the monoculture (2322 kg ha−1). On the loam site, crop establishment, growth, and yields responded negatively to reductions in tillage and weed management intensity. Barley stand establishment and weed control in CP and NT treatments on the loam site were less successful in the monoculture than in the rotation. No‐till grain yields (1494 kg ha−1) were on average 7% lower than CP yields (1608 kg ha−1), and 29% lower than MP yields (2076 kg ha−1). Rotation had no effect on grain yields on the loam site. Findings confirm the potential of conservation tillage to generate sustained yield returns in spring barley cropping systems, provided that proper attention is given to critical aspects of the cropping system, including crop establishment and weed management.