PNNL

Abstract

A Æeld experiment was conducted on a Typic Cryoboroll (Site 1) and a Typic Cryoboralf (Site 2) in north-central Alberta, Canada, to determine the inØuence of simulated erosion (artiÆcial topsoil removal) on loss in yield of hard-red spring wheat (Triticum aestivum L. cv. `Roblin'), and to determine to which extent fertilizers N and P will restore the lost crop productivity of two artiÆcially-eroded soils. There were three depths of topsoil removal (0, 10, and 20 cm) as main plot treatments, and a factorial combination of four levels of N (0, 50, 100, and 150 kg N ha?1) and three levels of P (0, 9, and 18 kg P ha?1) as subplot treatments. Wheat yields at both sites were markedly reduced by increasing depth of topsoil removal. The erosion effects were more pronounced at Site 2 where average yield on the 20 cm cut decreased to less than half of that obtained under noneroded conditions. At both sites, additions of fertilizer N and P to eroded soil increased wheat yield, but the yields did not match those obtained in non-eroded soil under the same fertilizer treatment. Plants growing on eroded soil responded differently to application of fertilizers N and P, not only in terms of yield but also in N and P concentration and uptake. The implication of these Ændings is that fertilization programs for Æelds with varying degree of erosion would require optimization of rates so as to restore yield and, at the same time, minimize nutrient losses (e.g., N leaching) and improve soil tilth. # 1998 Elsevier Science B.V. All rights reserved.