Cotton Development and Yield According to Nitrogen Application and Cover Crops.

Brazil is currently the fourth largest exporter and fifth largest cotton producer worldwide, with the highest production led by the State of Mato Grosso. The importance of cover crops has long been acknowledged in agriculture. The use of this cultivation practice can maintain or increase crop performance, reducing soil erosion, increasing organic matter content, improving the physical qualities of soil and decreasing the use of inputs like nitrogen fertilizer and pesticides.  Nitrogen application by covering and the maintenance of straw, conducted by direct seeding, should meet the needs of agriculture and promote soil conservation. This study evaluates the effect of pre-sowing nitrogen application in cotton crops and cover crops by direct seeding, on the development and yield of cotton crop. It was conducted in the county of Selvíria, State of Mato Grosso do Sul, Brazil, during the agricultural seasons of 2005/06, 2006/07 and 2007/08. The experimental design used was a randomized completely blocks in the factorial system consisting of three cover crops (wild radish, black oat and white oat) and four nitrogen levels (0, 30, 60 and 90 kg of N ha^-1) applied onto the millet straw and in pre-sowing of cotton. In April 2006, April 2007 and April 2008, the assessments of plant development and also harvesting of the experimental plots of cotton cultivars were conducted. The results showed that after planting the cover crops, the yield and development and the cotton plants increased with the use of pre-sowing N at 90 kg ha^-1, also showing that the wild radish is a coverage plant that provides increased cotton yield.