Reference values for assessing the nutritional status of soybean crops in Mato Grosso

Abstract

The objectives of this study were: a) to determine the reference values (standards) macro levels and micronutri loved, useful to the assessment of the balance sheet at Kenworthy method b) to assess the nutritional status of soybean crops in the degree of balance and obtain the potential for response to fertilization for nutrients. The work was carried out based on a database of leaf nutrient content and grain yield of 763 soybean crops in Mato Grosso, Campo Novo dos Parecis region, covering different agricultural years, cultivars, soil textures and time of use area with soybean culture. Considering macronutrients, on average 69,7% of low productivity crops are in the normal class, while for micronutrients this percentage is lower, 60.9%. N is the most frequently found nutrient in crops (83,2%) while Cu (49,8%) is the least frequent in the normal class. 78.3% of the crops have an adequate nutritional balance. Mg, P and Ca in the group of macronutrients and Cu, Mn and Zn in terms of micronutrients are those for which there are greater expectations of gains in crop productivity in response to fertilization.