Integrating perennial forage seed crops in the cropping systems in western Canada: An agroecological and economic assessment

Increasing functional diversity and integration of perennial crops in the crop sequences can enhance ecosystem services of cropping systems. Appropriate cropping sequence allows effective termination of preceding perennial crops, enhances establishment of succeeding crops and thereby generating rotational benefits in terms of productivity, profitability and environmental health. A cropping sequence study attempted to examine agroecological performance of cropping sequences integrating perennial forage seed crops in cropping systems. A replicated field experiment in split plot design comprised eight cropping sequences as main plot and three levels of N as sub-plot factors. Crop yields expressed as canola equivalent yield (CEY), gross margins and various soil property parameters such as aggregates, permanganate oxidizable C, microbial biomass C, and enzymatic activities of β-glucosidase, β-N-acetyl-glucosaminidase, acid phosphomonoesterase and arylsulfatase were compared. Perennial legumes grown as biennial seed crops in the sequence replaced N fertilizer requirement for succeeding wheat and canola crops by up to 90 and 45 kg N ha-1. Crop rotations between annual and perennial crops showed promising effects on agronomic and soil health parameters. However, short intervals between perennial seed crops in the cropping sequences posed difficulty in termination of previous crops leading to impaired establishment, volunteer competition and poor performance of following crops. Among the test crops, wheat followed by canola may be suitable transition crops in the cropping sequence following perennial legume seed crops, while peas followed by canola may be suitable transition crops after perennial grass seed crops for enhancing agro-ecological performance of cropping systems. Further studies are needed for comparative assessment of nutrients use efficiencies and environmental health of different cropping sequences.