Managing zinc deficiency in transplanted flooded rice by nursery enrichment. (156)
Keywords:Zinc deficiency, Transplanted rice, Alkaline soils, Root dipping, Nursery enrichment, Foliar spray, Seed soaking
AbstractZinc deficiency in flooded rice (Oryza sativa L.) requires developing inexpensive and practically adoptable technologies for managing the disorder on a worldwide basis. Dipping nursery roots in ZnO slurry, despite being economical, has never been adopted by the growers, primarily because of the heavy labour requirement. The present investigation, involving greenhouse and field experiments, compared a number of management practices aimed at alleviating Zn deficiency in transplanted flooded rice (cv. IR-6) grown in alkaline soils. Three alternate methods tried, i.e., nursery root dipping in ZnSO4 solution or ZnO slurry, and Zn-enriched nursery, proved equally effective or superior to the conventional ZnSO4 field-broadcast method. Contrary to earlier belief, Zn enrichment of nursery proved very effective even in severely Zn-deficient soils. Since the nursery area to be fertilized was far less than the field area, value:cost ratio (VCR) of the nursery enrichment was far better than the ZnSO4 field-broadcast. Moreover, Zn application to nursery beds was much easier compared to its broadcast in puddled fields. Therefore, considering the effectiveness, economy, and farmer-adoptability, seedling enrichment by ZnSO4 application to nursery beds at 20 kg Zn ha-1 is recommended to rice growers.