Osmopriming and Straw Mulching Improve Wheat Productivity under Water-Limited Conditions in the Old Brahmaputra Floodplain of Bangladesh

Abstract

Water scarcity during the critical stages of crop establishment and reproductive development can substantially constrain wheat (Triticum aestivum L.) productivity in the Rabi season of Bangladesh. Seed priming promotes early germination and metabolic activity, while residue mulching helps conserve soil moisture and reduce evaporation. A field experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from November 2023 to March 2024 to evaluate the individual and combined effects of seed priming and water-management practices on wheat productivity. The experiment was arranged in a split-plot design with three replications, comprising four seed-priming treatments and four water-management practices. Water management was assigned to main plots: no irrigation (W0), one irrigation at crown-root initiation (W1), two irrigations at crown-root initiation and at flowering (W2) and straw mulching at 6 t ha-1 (W3). Seed priming was assigned to subplots: no priming (P0), hydropriming with distilled water (P1), osmopriming with 13.5% polyethylene glycol (PEG) solution (P2) and halopriming with 1% CaCl2 solution (P3). Osmopriming consistently enhanced germination, plant growth, tillering, and dry matter accumulation compared with the unprimed control. It also produced the highest grain yield (4.06 t ha-1), straw yield (4.98 t ha-1), and biological yield (9.04 t ha-1) among priming treatments. Straw mulching similarly improved crop growth and productivity, producing 4.03 t ha-1 grain yield compared with 2.87 t ha-1 under no irrigation. The combination of straw mulching and PEG osmopriming (W3P2) produced the highest grain yield (4.48 t ha-1) and biological yield (9.54 t ha-1), whereas the unprimed, non-irrigated treatment (W0P0) produced only 2.46 and 5.64 t ha-1, respectively. These findings demonstrate that integrating PEG osmopriming with straw mulching can enhance wheat productivity under water-limited field conditions and provide a practical water-saving management option for wheat production in the Old Brahmaputra Floodplain of Bangladesh.