2017 ASHS Annual Conference

In maritime Canada, organic vegetables are usually produced in stockless farming systems. In this region, the standard recommended practice to maintain soil fertility in organic vegetable cropping systems is to implement a minimum four-year rotation comprising a single high-value vegetable crop in rotation with grain and legumes. This standard, or low-intensity, four-year organic rotation was compared with an high intensity four-year organic rotational system in which three high-value vegetable crops were grown in an integrated system using compost and innovative cover cropping and catch cropping strategies for soil building . The experiment was structured as a fully-phased, randomized block design with four replicates, beginning in 2008. Butternut squash (Cucurbita moschata Duschesene) was selected as the high-value vegetable crop common to both rotational systems. Butternut squash yielded between 25.9 t ha^-1 and 43.9 t ha^-1, varying by year but with no significant difference attributable to rotation. Lettuce (Lactuca sativa L.) (mean yield of 8.2 t ha^-1) and sweet corn (Zea mays L.) (mean yield of 9.4 t ha^-1) were also produced in the high intensity rotation. In the low intensity rotation soil organic matter remained near 3.2%, while in the high intensity rotation, it increased significantly over four years. Results of other measured parameters, including soil bulk density, plant-available soil N and nutrients measured using ion exchange membranes and plant tissue analysis, indicate that integrating compost, cover and catch cropping techniques can enable growers to produce multiple marketable vegetable crops in a four year rotation, diversifying risks and enhancing soil quality. An analysis of costs and revenues of the two systems showed that the low intensity system was profitable just one year out of the four. The high intensity system, though it engendered higher cost of production, was profitable three years out of the four, and had an overall profit that was 32% higher than in the low-intensity system.