- PRODUCTION -
Whether surface or sprinkler irrigation methods are used on soybeans,
Availability of moisture always ranks near the top when growth and yield factors are rated according to importance. Yields, up to a point, are determined by the availability and use of moisture. Irrigation is a means by which an adequate moisture supply to the crop can be better assured.
This provides a potential for increased yields over dryland production and the opportunity to stabilize year-to-year fluctuations in yield and seed quality. This yield stabilization can allow a more aggressive marketing program. In addition, loaning agencies in some areas are evaluating the percentage of a grower’s soybean acreage that can be irrigated before they issue the producer a crop production loan.
By the soybean’s reproductive growth period, when irrigation is often first needed, approximately 50 to 60 percent of the production costs are already invested in the crop. Irrigation serves as insurance against a drought that can result in yields that do not even cover production costs, especially for double-crop soybean production.
Daily water use varies as the crop develops. Germination and seedling stages use 0.05-0.10 inch per day, and the rapid vegetative growth stage uses 0.10-0.20 inch per day. Once the plant reaches flowering to pod fill (full canopy), it uses 0.20-0.30 inch per day. And from maturity to harvest, the plant uses 0.05-0.20 inch per day.
Early and late-season irrigation
Most growers realize the need to irrigate when the crop is blooming and setting pods. However, experience indicates that many growers tend to be late with the first irrigation and then quit irrigating before the crop can reach its full potential. The lack of early and late-season irrigation is often responsible for a soybean crop not reaching its irrigated yield potential.
Although irrigation is an important factor in consistent and profitable soybean production, it is not a cure-all. Maximum yield and profit will be achieved only when irrigation is coupled with other production practices that establish profitable yield potentials.
University of Arkansas Division of Agricul-ture provided information for this article.