Northeast Research and Demonstration Farm

Legume Identity and Timing of Incorporation Effects on Soil Responses to Green Manure

Authors: Rhonda Graef (Iowa State University) , Cynthia A. Cambardella (USDA National Soil Tilth Lab) , Matthew Z. Liebman (Iowa State University)

Abstract

Challenges to sustainable agriculture include optimizing nitrogen (N) availability, maintaining profitability by reducing input costs, such as synthetic N fertilizers, and minimizing the loss of nitrate-N. Production of a legume green manure in a crop sequence is a typical method used to reduce or eliminate the need for applying synthetic N fertilizer to succeeding crops. Legumes or legume/small grain mixtures are often used as green manures because of the symbiotic association of most legume species with N fixing Rhizobium bacteria. The dynamics of nitrogen (N) mineralization in the soil after legume incorporation are complex. To contribute adequate amounts of plant-available N to the subsequent crop, the incorporated green manures must decompose sufficiently and in synchrony with the N demand of crops such as corn.

Keywords: Agronomy

How to Cite: Graef, R. , Cambardella, C. A. & Liebman, M. Z. (2004) “Legume Identity and Timing of Incorporation Effects on Soil Responses to Green Manure”, Iowa State University Research and Demonstration Farms Progress Reports. 2003(1).