Soil management and N fertilization for rice

The use of sprinkler irrigation for rice (Oryza sativa L.) crop is a relatively recent practice in Brazil. Therefore, crop soil and fertilization management are still not very well defined. Another problem is the inexistence of specific cultivars adapted to this cropping system. This study aimed to evaluate sprinklerirrigated upland rice cultivars under different soil management practices and nitrogen sidedressing rates in relation to yield and grain quality. A randomized block design was used, arranged as a 3 x 3 x 5 factorial scheme, totaling 45 treatments consisting of the combination of three rice cultivars (Primavera, Confiança and Maravilha), three soil management systems (disk harrow + levelling harrow, moldboard plow + levelling harrow and no-till) and five nitrogen rates, applied as sidedressing (0, 25, 50, 75 and 100 kg ha), with four replicates. The experiment was set up during the 1999/2000 and 2000/2001 cropping seasons, in Selvíria, MS, Brazil, on a Typic Haplustox of clayey texture. Cultivars Primavera and Maravilha presented higher grain yield than Confiança; on the other hand the latter showed higher milled and head rice yields during seed processing. Soil tillage with the moldboard plow and no-till interfered positively in the agronomic and productive characteristics of the crop. In relation to milled rice yield, tilling with the levelling disk + moldboard plow showed better results in relation to no-till. Nitrogen sidedressing did not interfere with the agronomic and productive characteristcs as well as with the milled rice yield of all cultivars.