DAIRY COMPOST UTILIZATION IN CROPPING SYSTEMS

Composted dairy manure applications were evaluated for four years in crop production at Kimberly, Idaho. Optimum dairy compost rates considering economic, agronomic and environmental factors for sustainable crop production were determined. Sweet corn for seed had adequate nutrients available for production, with compost not significantly increasing yield over the control. The optimum compost rate for potato production was 2.5 tons/acre (T/A) compost plus 150 lbs nitrogen (N)/acre (A) of commercial fertilizer. In organic potato production an application rate of 5-10 T/A of compost and then holding it in the “soil bank” for several years would be advantageous, as long as the fields are level with little chance for soil erosion and loss of nutrients into water sources. Malt barley production was good with 2.5 T/A of compost, but maximum profits were obtained with no compost and 60 lbs N/A of fertilizer. Sugarbeet production was optimized with 2.5 T/A of compost and 100 lbs N/acre of fertilizer.