Pre-harvest desiccation on yield and seed quality of soybeans

Abstract

Field and laboratory investigation were conducted to evaluate the effects of desiccants and seed quality of soybean (Glycine max (L.) Merrill. ‘Evans' and ‘Hodgson' cultivars were treated with two rates of glyphosate and paraquat at two seed moisture stages near physiological maturity. The plants were harvested at weekly intervals after desiccation. Desiccation effects were evaluated by studying seed yield, seed moisture, standard germination test, and seed weight. Seed yield was not reduced after desiccation with glyphosate and paraquat when applied at 40 and 30% seed moisture level. The soybean cultivars, ‘Evans' and ‘Hodgson', responded similarly to desiccation. The higher yield of ‘Hodgson' was probably due to higher inherent yielding ability. Both desiccants were effective in reducing seed moisture content in these conditions. High temperature and low relative humidity in the field hastened action of chemical treatment in reducing seed moisture content. These results are in agreement with those of other workers who conclued that either paraquat or glyphosate is available as a chemical desiccant to hasten soybean seed harvest and prevent seed deterioration in the field. The desiccation accelerates seed drying rate, improves seed quality and scheduling of harvesting, and reduces seed borne disease and seed deterioration, thus allowing best harvest.