YIELD AND N-UPTAKE OF BARLEY ON 2 ARTIFICIALLY ERODED SOILS IN NORTH-CENTRAL ALBERTA

Topsoil depth is an indirect indicator of soil quality and crop produc tivity. A 2-yr field study was conducted in north-central Alberta with the following objectives: (I)to determine aboveground barley dry matt er yield, N uptake, and fertilizer-use efficiency (FUE) in two artific ially eroded soils of contrasting properties, and (2) to assess the ef fectiveness of KNO3 and urea in compensating for lost productivity. Fi eld experiments were conducted on an Orthic Gray Luvisol (Site 1) and on an Eluviated Black Chernozem (Site 2) in 1991 and 1992. The treatme nts consisted of three depths of topsoil removal (0, 10 and 20 cm) and three N fertilizers (KNO3 and urea at 150 kg N ha(-1), and the contro l). The plots were sown to barley (Hordeum vulgare L.). Yields and N u ptake of aboveground barley dry matter decreased with each increment o f topsoil removal and were lowest in the 20-cm topsoil removal. Fertil izer N improved yields and N uptake at each depth of erosion. In most of the erosion treatments barley yields and N uptake tended to be grea ter with KNO3 than with urea. The effectiveness of each N source, howe ver, varied with site. At the 20-cm depth of erosion, KNO3 was more ef fective than urea. The trend in fertilizer-use efficiency increased wi th depth of erosion at Site 1 but decreased at Site 2.