Agronomic evaluations of nine decades of soybean cultivars: Nitrogen Fixation;
Seth Naeve ( University of Minnesota), Shaun Casteel ( Purdue University), Shawn Conley ( University of Wisconsin), Vince Davis ( University of Illinois at Urbana-Champaign) ($45000). The Project Manager's email is firstname.lastname@example.org.
Key Words: Soybean Aphid - Biocontrol, Soybean Aphid, Soybean Aphid - Management
National soybean yields have increased from 11 bu/acre to 43 bu per acre over the past 90 years with an average gain of 0.34 bu per acre per year. These yield gains are attributed to advances in genetics, pest control, and production practices. Breeding efforts usually receive the greatest credit to the yield gain rate with little attention to agronomic management. Future soybean production necessitates a greater rate of yield gain to meet exponentially growing demands. The research aims to understand the advances in agronomic management and soybean breeding over the past nine decades. The overall goal is to improve future production practices and breeding efforts of soybean based on past results. Four agronomic evaluations (nitrogen utilization, planting date, seeding rate, disease resistance) of nine decades of soybean cultivars were initiated in 2010. Indiana and Illinois evaluated 59 maturity group (MG) III cultivars, while Wisconsin and Minnesota evaluated 60 MG II cultivars. All four trials were evaluated at each state with Indiana leading the Nitrogen (N) utilization trial, which is the focus of this proposal. Indiana’s preliminary results exhibited a gain of 0.5 bu per acre per year with the fertilizer N supply (500 lb of N per acre) compared to a gain of 0.4 bu per acre with N supply from the soil and biological nitrogen fixation. The hypothesis is that yield gains are due to increased N use efficiency and enhanced nodulation by newer soybean release years. Data from collaborating states and a second year (2011 growing season) are needed to draw conclusions on breeding efforts and agronomic management. The field experiment addresses N utilization, but is very limited in interferences of nodulation efficiency. Therefore, the nodulation of these ~60 cultivars will be examined in the greenhouse. The proposed study will evaluate nine decades of soybean cultivars (~60 cultivars) in four agronomic trials: (A) Nitrogen Utilization Efficiency, (B) Planting Date, (C) Seeding Rate, and (D) Disease Resistance. These four trials are to be evaluated in four major soybean producing states (Indiana, Illinois, Wisconsin, and Minnesota) to total four locations for each trial. The overall goal is to determine the sources of yield gains over the past 90 years of breeding when factored by agronomic management.
This project is funded by Indiana Soybean Alliance