Manure Slurry-enriched Micro-site Seeding of Biosuppressive Covers

There is increasing interest among growers in novel establishment systems for cover crops that can rehabilitate and protect soil. Cropping intensification has led to yield declines, compacted and poor quality soil, and increased pest problems. Cover crops in the Brassica (mustard) family offer benefits in soil conservation, improvement in soil quality, reduction in nitrate leaching, and suppression of certain pests and soil borne fungal diseases. Establishment of cover crops by conventional methods following harvest presents a significant challenge as soil is generally dry, compacted, uneven, and far from an ideal environment for seed germination. An alternative method, manure slurry-enriched micro-site seeding, incorporates aeration tillage, manure application, and seeding in a single operation. The objective of this work was to evaluate manure slurry-enriched micro-site seeding of cover crops by assessing stand establishment and biomass yield of oilseed radish and oriental mustard. The species were chosen for contrasting seed size, thus allowing evaluation of how small versus medium seeded brassica respond to aeration tillage, manure application, and seeding done in a single efficient ’manure slurry-enriched micro-site seeding’ operation. Results of field trials in 2004 and 2005 were consistent with the new manure slurry seeding process as an efficient and effective cover crop establishment method. Compared to direct-drilling, manure slurry seeded plant stands (plants m-2 ) were significantly less ( = 0.10) in five of seven comparisons but biomass yields (kg ha-1) were similar because individual plant biomass was up to six times greater with manure slurry seeding. Biomass (aboveground and total) of manure slurry seeded plants was significantly greater in two of seven comparisons and there were no instances when the conventionally seeded crops yielded significantly more than the manure slurry seeded crops. Seed size did not affect the success of the manure slurry seeding method.