The feasibility of inter-cropping pea with canola, mustard, and barley

An inter-cropping trial was conducted in the summer of 1988 to compare pea inter-crops with Tobin and Westar canola, yellow mustard, and barley. At two sites, a number of different pea varieties were inter-cropped with canola, mustard, and barley, and compared to mono-crops of each. At four sites, a seeding rate trial was conducted with Westar canola and barley inter-crops with Trapper pea. Measurements to assess the success of the inter-crop included grain yield, land equivalent ratio (LER), grain nitrogen yield, and economic return. In the variety trial, inter-cropping reduced the yields of both component crops, and the LER was not significantly higher than 1 in any case. There were significant differences in economic return for the crop. Inter-cropping did not increase the $/ha return, while pea mono-crops provided the greatest income. Significant differences in grain N yield were also observed, with pea varieties being highest. Little or no increase occurred in grain N yield when pea was inter-cropped with barley. In the seeding rate trial, inter-cropping again did not benefit yield nor economic return. Some benefit resulted from inter-cropping barley with pea, as this increased the grain N yield as compared to mono-cropped barley. Although neither yield nor economic return was consistently increased by inter-cropping, other benefits to the pea were noted. Lodging of pea was reduced, especially when inter-cropped with mustard or Westar canola. This could facilitate harvest, and reduce associated grain loss. In addition, the pea crop would be less subject to pre-harvest weather damage, thus producing a higher quality crop.