Forage from Soybean Provides an Alternative to Its Poor Grain Yield in the Southern Great Plains

Abstract

The economic potential for soybean (Glycine max L. Merr.) as forage, compared to its potential as grain, creates a dilemma for soybean farmers in the southern Great Plains. To better understand these two potential uses, soybean cultivars differing in maturity and growth habit were planted in 14-inch and 28-inch rows on 11 May 2001 and 16 May 2002 near Dallas, TX. The soil was a Houston Black Clay (fine, smectitic, thermic Udic Haplusterts). Plant height, plate meter readings, and forage biomass were measured in July and August and grain yield determined in September. Forage (1.26 to 2.13 ton/acre) and grain yields (9.3 to 20.9 bu/acre) were relatively low and similar between row spacings and between cultivars. Forage quality traits ranged as follows (by dry weight): crude protein (8.7 to 17.2%), acid detergent fiber (24.1 to 33.6%) and neutral detergent fiber (33.2 to 48.9%), in vitro dry matter digestibility (69.2 to 78.6%), and relative feed value (120 to 196). Plate meter readings and plant height were each correlated to biomass in one season but not both. Because of its relatively high forage quality and low grain yields, harvesting any of the soybean cultivars for forage during mid-season would have been more profitable than harvesting for grain, given the hay and grain market prices when the experiments were conducted.