Economically Optimal Plant Population Density in Midsouth Soybean Production

Economically Optimal Plant Population Density in Midsouth

Soybean Production

Abstract

            Soybeans are an important crop on many cotton farms in the Midsouth. The cost of soybean production is increasing with rising input costs. In particular seed has become one of soybean farmers’ most expensive inputs. In response to rising costs, farmers are looking to established production techniques such as plant spacing, specifically narrower row spacing and higher plant population densities (PPD), as well as the adoption of new practices such as early soybean production systems (ESPS) to help better utilize increasingly expensive inputs such as seed. The objective of this research was to estimate an economically optimal plant population density (EOPPD) considering row spacing, seeding rate, and input-output prices. Using data collected from field experiments during 2005, 2006, and 2007 at the University of Tennessee Research and Education Center at Milan, Tennessee a yield response function will be established with respect to PPD, row spacing, and an Ångström weather index variable. Several functional forms will be fitted, using the Likelihood Dominance Criterion (LDC) to establish which form best fits the data. Then through the use of a partial budgeting framework a net returns equation will be developed and used to assess the EOPPD. Evaluation of this model will include various sensitivity and breakeven-analysis. Sensitivity analysis will allow for the evaluation of the effects on net returns and EOPPD of changes in input and output prices. Also, break-even analysis will facilitate the estimation of prices and yields necessary for farmers to cover their costs of production.