Cumulative Effects of Pre-sowing Seed Treatment and Foliar Application of Salts in Improving Biomass and Grain Yield of Soybean in Moderate Saline/alkaline Soil

Field trial studies were carried out to find out whether performance of soybean could be improved as a result of pre-sowing soaking treatment of seeds. Comparatively pre-sowing seed treatment with KNO₃, NaNO₃, NaCl, thiourea and di-Ammonium phosphate (DAP) resulted in better development of the root and shoot system than the control. As a result of pre sowing seed treatment, there was an increase in dry matter production by 44, 27 and 32 % over the control in KNO₃, NaNO₃ and DAP treatments respectively. Similarly increase in seed yield was noticed in NaNO₃ (45 %), KNO₃ (40 %) and DAP (50 %) pretreated plants. The number of existing nodules was reduced both in the control and treated plants due to pH (8.4) of the soil.
To investigate the cumulative effects of foliar spray on plants raised from pre-sowing seed treatment, salt solutions (NaCl, KNO₃, NaNO₃, thiourea, DAP) at optimal level were sprayed separately three times at three different stages of development. As a result of foliar spray moderate increase in growth in KNO₃ (20 %), thiourea (29 %) and DAP (25 %) treatment was observed over the control. Seed yield increased significantly (56–70 %) in all treatments except NaCl spray, due to increase in the number of pods (41–63 %) per plant. Foliar spray of nutrients increased protein yield without affecting the oil content. It is suggested that a considerable fertilizer economy may be effected by coupling pre-sowing seed treatment with foliar fertilization.