Impact of tillage and landscape position on nitrogen availability and yield of spring wheat in the brown soil zone in southwestern Saskatchewan
Jowkin, V. and J.J. Schoenau. 1998. Can. J. Soil Sci.78:563-572
Abstract
Nitrogen availability to a spring wheat crop was examined in the cropping season in a side-by-side comparison of no-till (first year) and tillage fallow in an undulating farm field in the Brown soil zone of southwestern Saskatchewan. Thirty different sampling points along a grid in each tillage landscape were randomly selected, representing 10 each of shoulder, footslope and level landscape positions. Nitrogen availability was studied: i) by profile inorganic N content, ii) by crop N uptake and yield of spring wheat (Triticum aestivum L.), and iii) by 15N tracer technique and in situ burial of anion exchange resin membranes (AEM). Pre-seeding available moisture content of the surface soil samples was significantly higher under no-till compared with tillage fallow. However, no significant differences in pre-seeding profile total inorganic N, crop N uptake and yield were observed between the treatments. At the landform scale, shoulder positions of the respective tillage systems had lower profile inorganic N, crop N uptake and yield compared with other slope positions. Soil N supplying power, as determined by 15N tracer and AEM techniques, was not significantly different between the tillage treatments, indicating that N availability is not likely to be greatly affected in initial years by switching to no-till fallow in these soils under normal moisture conditions.
Key Words
Summerfallow, landscape, nitrogen, wheat
