Influence of tillage and liquid swine manure on productivity of a soybean-barley rotation and some properties of a fine sandy loam in Prince Edward Island

Interactions between tillage management for manure incorporation and rate of manure application may influence crop productivity and soil properties. This study was conducted to evaluate the effect of liquid swine (Sus scrofa L.) manure (LSM) applied at three N rates (40, 80, 160 kg ha(-1)), compared with mineral N fertilizer, in a 2-yr barley (Hordeum vulgare L.)-soybean (Glycine max L. Merr.) rotation, incorporated by two tillage methods (chisel plough and disc), on crop yield and quality and some soil properties, especially C parameters. The LSM was applied every second year in the spring, prior to barley seeding. The study was conducted over a 5-yr period on a Charlottetown fine sandy loam (Orthic Humo-Ferric Podzol) in Prince Edward Island. The experimental design was a split-plot with four replicates. Soil samples (0-60 cm) were obtained at the termination of the study to determine residual effects of the LSM on soil properties. The two methods of LSM incorporation had no differential effect on crop response. Generally, increasing the application rate of LSM increased the barley yield, but had no effect on grain N concentration. A residual effect on crop grain yield for the high rate of LSM was evident in the soybean year. Crop response to LSM was similar to that of mineral fertilizer. Application operations for LSM had no adverse effect on soil strength or soil bulk density. Soil properties (microbial biomass C, carbohydrates, water-stable aggregates) were not greatly influenced by LSM application, however, increases in particulate C (POM-C) were evident for the high LSM rate at the 10- to 30-cm soil depth. The study showed that for fine sandy loams in Prince Edward Island low to medium rates of LSM applied every second year could serve as a source of N for barley in barley-soybean rotations.