Enriching Rice Grain Zinc through Zinc Fertilization and Water Management Soil Fertility & Plant Nutrition (original) (raw)

Increasing rice (Oryza sativa) grain-Zn concentration is important for achieving improved human nutrition. our objective was to understand how agronomic management practices, including water management and fertilizer-Zn application rate and timing, affect plant growth, grain-Zn concentration , and yield of rice genotypes. In a series of four-field experiments over three seasons, we tested multiple combinations of water management techniques and fertilizer-Zn application techniques. The use of alternate wetting and drying (AWd) water management increased (p < 0.001) soil redox potential and diethylene triamine pentaacetic acid (dTPA)-extractable soil Zn compared with continuous flooding (CF) in the 0-to 2-cm soil depth, but not always in the 2-to 10-cm depth. on average, AWd grain-Zn concentration increased 9% over CF without any yield penalty. Fertilizer-Zn application increased dTPA-extractable Zn only in the top soil layer and only temporarily , with a corresponding increase in grain-Zn concentration only at rates > 10 kg Zn ha-1. different timings of fertilizer-Zn application (from basal to flowering) had no effect on grain-Zn concentration or yield. overall, our results indicated that AWd had a consistent and larger positive effect than fertilizer-Zn application on grain-Zn concentration. However, the increase in grain-Zn concentration due to fertilizer-Zn or water management was small, up to 2 mg Zn kg-1 brown rice, implying that improved agronomic management alone is not sufficient to meet the target increase of at least 10 mg Zn kg-1 , but is a useful complementary strategy for enhancing the performance of Zn-enriched rice by improving soil-Zn availability.