Use of Compost to Produce High Yield Soybean.

This research study is designed to evaluate the use of solid-separated compost (solids removed from liquid swine manure, composted with urban landscape waste) as a high yield soil amendment for soybean (Glycine max) production. The entire experimental site (4 contiguous ha at Illinois State University Farm at Lexington, IL, USA) has uniform soil (Parr-Libson-Drummer Association). The 4.0 ha site has been split into two ‘blocks' of 2.0 ha each. One block was planted into corn (Zea mays), and the other block into soybean to allow for a corn/soybean rotation between the blocks. Representative agronomic practices for most Illinois producers (except for compost) will be utilized for corn and soybean blocks at this experimental site. For the 2.0 ha block planted to soybean or corn, two 1.0 ha “plots” were established. One 1.0 ha plot was the “control” that did not receive solid-separated compost. The 1.0 ha plot (“high yield”) received solid-separated compost (supplied at 17.8 Mg/ha, on dry weight basis). Soil samples and plant tissue and productivity data were collected during the 2010 and 2011 growing seasons. Data were analyzed using a two sample t test (equal variance), with years considered as repeats. Preliminary results indicate that soybean yield was increased by 13.2% (p = 0.21) via the application of compost. The greater yield of the compost treatment could be due to a 15% increase (p = 0.05) in plant dry weight, with concurrent increases in pod and seed number. The annual application of compost also increased soil P levels by 154% (p = 0.07), as compared to the control. Additional data is needed to ascertain seasonal variation and long-term effects of compost application on soybean productivity. The ultimate impact of this study is to improve soybean yield in an environmentally sensitive and sustainable manner.