Including grain-legumes in cropping systems contributes to a reduction in greenhouse gas emissions and enhances agronomic and economic performance of cropping systems. The objective was to examine the potential for increasing the frequency of field pea ( Pisum sativum L.) (FP) in a spring wheat ( Triticum aestivum L.) (W)-based cropping system. Three crop rotations, continuous pea (C-Pea), W-FP, and W-W-FP, were evaluated over a 10-yr period (1998-2007) at Indian Head, SK. During the FPphase of C-Pea and W-FP, three starter N rates (5, 20, 40 kg N ha -1) were applied. One rate of N (80 kg N ha -1) was used in W. Rotation and N had similar effects on plant densities in either crop. Field pea grain yields were 25% lower with C-Pea than W-FP or W-W-FP but similar between W-FP and W-W-FP. Starter N had some effect on FP grain yields at the higher N rate in W-FP but not C-Pea. Spring wheat grain yields were 3% greater on FP than W stubble. Grain protein in FP was 3.1% higher on C-Pea than W-P or W-W-FP while grain protein in W was 1 g kg -1 higher on FP than W stubble. Crop water use efficiency in FP and W was not affected by crop rotation. Based on the results of this study, we conclude that the frequency of FP in cropping systems in the subhumid and semiarid areas can be increased intermittently with only a 1-yr cereal break between FP crops when combined with proper integrated crop management practices.
