The Effect of Compost and Seed Inoculation Treatments on Selected Physical and Biochemical Properties of the Soil, Nodule Occupancy, and Soybean Yield

Author

Kathleen Elizabeth Holthaus, Southern Illinois University CarbondaleFollow

Date of Award

8-1-2012

Degree Name

Master of Science

Department

Plant and Soil Science

First Advisor

Klubek, Brian

Abstract

Field experiments were conducted in 2010 and 2011 in Carbondale, IL assessing the effects of compost and seed inoculation treatments on selected soil properties, nodulation, and soybean yield. The main treatment was a seed inoculum consisting of B. japonicum, S. kanamyceticus, and P. putida, and the sub treatment was a compost application at 0, 22.5 or 45 Mg ha-1 (fresh weight basis). Data was collected regarding early nodulation, nodule number, nodule occupancy, leaf nitrogen content, soybean yield, seed nitrogen, protein and oil content, selected enzyme activity, and the soil physical properties of water content by weight, water content by volume, bulk density, porosity, and water filled pore space. For 2010, the inoculation treatment significantly (P<0.05) increased soybean yield and affected the soil physical properties water content by volume, bulk density, porosity, and water filled pore space. The 45 Mg ha-1application of compost increased early plant growth, soybean yield, seed nitrogen, and seed protein content. Dehydrogenase activity was also increased by compost application. For 2011, the inoculation treatment increased leaf nitrogen content, suggesting that the applied inoculum successfully infected, nodulated, and increased nitrogen fixation by the inoculated soybeans. The 45 Mg ha-1 compost treatment also increased soybean yield and improved the soil physical properties of bulk density and porosity.