Effect of tillage and residue management on barley and canola growth and water use efficiency

Residue management and tillage are used to reduce the effect of water defic it or excess on crop production in northwestern Canada. This study was cond ucted on Donnelly silt loam and sandy loam soils (both Gray Luvisols) to ev aluate the effects of conventional tillage (CT), no-tillage (NT) and modifi ed NT (MNT, i.e., NT with 75-mm wide residue-free strip over the planting r ow) on barley (Hordeum vulgare L) and canola (Brassica campestris L.) dry m atter accumulation and grain production, water depletion and water use effi ciency (WUE) in 1992 and 1993. Infiltration rates (I-c), soil water content , plant dry matter and grain yields were measured. The I-c of the two soils was greater than the rainfall rate (R-r) in both years, suggesting that th ere was no runoff In 1992, a dry year, barley grain yields were significant ly greater by 16% on the silt loam and by 17% on the sandy loam under MNT a s compared with CT. The MNT increased barley grain yield by 3% compared wit h NT on the silt loam and increased canola grain yield by 12% on the sandy loam soil in 1993, which was a wet year. Dry matter accumulation and grain yield of barley in CT were adversely affected by a prolonged early dry peri od in 1992. Abundant rainfall slowed barley and canola growth and depressed yield in the NT in 1993. From seeding to harvest in 1992, WUE for barley g rain production on the silt loam was greater by 21% in the NT and by 18% in the MNT as compared with the CT, which bad a WUE of 5.25 kg ha(-1) mm(-1); it was greater by 19% in the NT and by 10% in the MNT compared with the CT on the sandy loam soil with a WUE of 5.07 kg ha(-1) mm(-1). In 1993, NT an d MNT had lower WUE, which coincided with lower grain yield as compared wit h CT.