Submitted to: Agronomy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2010
Publication Date: 5/1/2010
Citation: Hedtcke, J.L., Posner, J.L., Hall, J.A., Walgenbach, R.P. 2010. Orchardgrass Ley for Improved Manure Management in Wisconsin: I. Forage Yield, Environmental Impact, and Production Costs. Agronomy Journal. 102:1-9. Interpretive Summary: Most dairy farms in the north central and northeastern U.S. continue to grow most of their feed and recycle the manure nutrients on the farm. Corn and alfalfa are the most commonly grown dairy feeds in these regions. Unfortunately, this common corn and alfalfa crop rotation leaves the dairy farmer with few spreading windows to make efficient use of the nitrogen in manure. Previous research has suggested that a grass hay phase would create a number of summer spreading windows and might be a logical, cost-effective solution for improved manure management. In this 4-year study we compared 2 cropping systems with 2 fertilizer options: 3 years of continuous corn silage or orchardgrass hay with either manure or commercial fertilizer. In a 4th year, a test crop of corn silage was grown following both systems. While the corn silage system had fewer variable costs and produced more dry matter in the first 3 years, in the 4th year the corn silage following grass produced more dry matter than the corn silage following corn silage. The grass system also offered several summer windows for spreading manure. This information is useful to dairy farmers who must spread manure in the summer and are looking for cropping options to facilitate this need.
Technical Abstract: 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 (GL) does open several windows for manure spreading. The effects of such a strategy were examined in a 3-yr, 2 by 2 factorial trial comparing orchardgrass (Dactylis glomerata L.) and corn silage (CS) with either manure or fertilizer at two locations in Wisconsin. In the fourth year a test crop of CS was grown following both crops. During the first 3 yr, the manured corn plots out-produced the manured grass plots (16.0 vs. 8.6 Mg DM ha-1 yr-1) but in the fourth 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 (STP) values climbed 2 to 4 mg kg-1 yr-1 and soil test potassium (STK) 14 to 20 mg kg-1 yr-1 under the manured systems. Variable costs per metric ton of forage dry matter (DM) were significantly higher in the manured GL compared to manured continuous CS 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 GL may be an ecologically and economically sound strategy where summer manure spreading is required.