Níveis de tecnologia na semeadura de arroz irrigado na fronteira oeste do Rio Grande do Sul

Abstract

The use of seed quality and adequate seeding density provides a better initial establishment of the crop, guaranteeing an adequate population of rice plants. The cost of producing high rice and the low purchasing power of the producer to undertake technology entails using high sowing densities to meet germination failures and to choose between different modes of seed treatment (industrial, on the farm and not to treat them) . The objective of this work was to evaluate three levels of technology (low, medium and high) differing in the mode of seed treatment and density of sowing in irrigated rice crop in the Western Border. Seeds of cultivar IRGA 424 CL were seeded at 17 cm spacing with Semeato SHP 209 seed plotter. The work was based on 3 technological levels: Low technology sowing (B) was sown at 120 kg ha-¹ density, this level referred to the saved seed or "white bag" that growers set aside for multiplication. The second technological level presented treatment of seed with certified seed, but on-farm treatment of insecticide and fungicide, with densities of 60 and 100 kg ha-¹, denominated average level (M). The third technological level refers to a seed with industrial seed treatment (TIS) with a complex of products that includes fungicides, insecticides and micronutrients and biostimulant, with a density of 60 kg ha-¹, called high (A) technological level. The experimental design was a randomized complete block design with four replications. Evaluations were performed using the yield components (number of panicles m-², weight of 1000 grains and panicle-¹ grains), as well as productivity (kg ha-¹) and grain quality (percentage of sugarcane yield , Percent yield of whole grains, white center index and percentage of broken grains). The results were submitted to analysis of variance and regression using the Tukey test at 5% of probability. Low sowing densities associated with medium and high technology levels are recommended for irrigated rice seeding.