Yield and economics of traditional and early soybean production system (ESPS) seedings in the midsouthern United States

Abstract

Drought stress reduces yield of traditional May and June seedlings of soybean in midsouthern USA. Field experiments using Maturity Group (MG) IV and MG V soybean cultivars were conducted at Stoneville, Mississippi (latitude 33°26′ N) for five years to determine effects of earlier-than-normal (April) and normal (May) seeding on net returns from soybean grown with, and without, irrigation. Net returns were calculated as the difference between income and all direct and indirect costs excluding those for land, management, and general farm overhead. In the irrigated environment, average net returns from April seedings of MG IV cultivars were greater than those from May seedings in all years, while average net returns from April seedings of MG V cultivars were greater than those from May seedings in all years except 1997. These greater net returns resulted from larger seed yields, lower estimated costs, higher prices received for harvested seed, or a combination of the three. Average net returns from April seedings ranged from US$ 148 to US$ 617/ha, while average net returns from May seedings ranged from US$ 69 to US$ 567/ha. Use of MG IV vs. MG V cultivars had no consistent effect on net returns from either April or May seedings. In the nonirrigated environment, average net returns from April seedings of all cultivars were greater than those from May seedings in all years. Average annual net returns from cultivars seeded in April ranged from US$ 74 to US$ 374/ha, while average annual net returns from May seedings ranged from US$ −9 to US$ 325/ha. In three of the five years, MG V cultivars sown in April produced more yield and greater net return than did MG IV cultivars, while April-sown MG IV cultivars produced the highest yield and net return in one of the five years in the nonirrigated study. These results indicate that earlier-than-normal (April) seedings of either MG IV or MG V soybean cultivars will result in increased net return vs. that attained from traditional (May or later) seedings in the midsouthern USA. These results also indicate that choosing cultivars within an MG is more critical than choosing between MG IV and V.