Effects of four potassium doses on six sprinkler irrigated rice upland cultivars. II. Outcome of grain processing.

Abstract

The effects of four potassium rates (0, 20, 30, and 40 kg/ha of K2O, as potassium chloride) on the outcome of grain processing of six upland rice cultivars (IAC-20, Carajás, Caiapó, Canastra, Araguaia, and Cirad 4) were studied. Half the dose of potassium was applied at sowing and the other half at flowering onset (50% of the plants starting panicle emission). All plots received a basic fertilization of 40 kg/ha of P2O5 (simple superphosphate), 0 kg/ha of N (ammonium sulphate) and 60 kg/ha of N (urea) 30 days after seedling emergence. Plants were irrigated with a central pivot equipment. Hectoliter weight, percentage of polished grains, percentage of whole grains, and percentage of broken grains were evaluated. Potassium affected the percentage of broken grains, polished grains and whole grains. Potassium reduced significantly the percentage of broken grains. A significant genotypic effect was observed.Additional keywords: dryland rice; grain quality; supplementary irrigation; fertilization.