Orchardgrass (Dactylis Glomerata L.) Ley for Improved Manure Management in Wisconsin: I. Forage Yield, Environmental Impact and Production Costs

Spreading dairy manure in climatic zones with a short growing season that are dominated by full season crops such as corn (Zea mays L.) and alfalfa (Medicago sativa L.) is a challenge. However, replacing these with a grass ley does open several windows for manure spreading. The effects of such a strategy were examined in a three-yr, 2×2 factorial trial comparing orchardgrass (Dactylis glomerata L.) and corn silage with either manure or fertilizer at two locations in Wisconsin. In the fourth year a test crop of corn silage was grown following both crops. During the first three years, the manured corn plots out-produced the manured grass plots (16.0 vs. 8.6 Mg DM ha-1 yr-1) but in the 4th year the corn following the orchardgrass ley system was more productive than when following corn (20.7 vs. 14.9 Mg DM ha-1). Soil test phosphorus values climbed 2-4 mg kg-1 yr-1 and soil test potassium 14-20 mg kg-1 yr-1 under the manured systems. Variable costs per metric ton of forage dry matter were significantly higher in the manured grass ley compared to manured continuous corn silage system ($67 vs. $43 Mg-1). This can be considered a worst case scenario due to the frequent manuring in the ley system. Also, it is difficult to include the managerial and economic advantages of having adequate summer manure spreading locations. Thus, including a grass ley may be an ecologically and economically sound strategy where summer manure spreading is required.

Published in Agronomy Journal 2010 vol. 102:956-963