Much of the Brazilian corn has been grown in the second crop after soybeans, but there is still no accurate information on its response to N, as well as on the consequences on the next soybean crop. The hypothesis is that the residual N left by soybean, mainly in corrected soil, can be used by the maize grown next, which should respond to lower doses of nitrogen fertilizer. The objective of this work is to evaluate the efficiency of the use of N by maize cultivated in a consortium with Panicum maximum in the second harvest and the dynamics of N in the soil in under no-till as affected by correction of soil acidity using lime and gypsum. A subsequent experiment was carried out on the soybean crop with maize in consortium with Panicum maximum in the agricultural years of 2017 and will be conducted until 2019. The treatments include the application of lime, lime + gypsum and control (without application of correctives) in the and four N doses (0, 80, 160, 240 kg ha-1 N) applied to the maize culture. In the treatment with 160 kg ha-1 N will be applied ammonium sulfate enriched in 15N, to evaluate the use of N fertilizer. Soil from the experimental area was sampled (0-10, 10-20, 20-40, 40-60 and 60-80 cm depth) before to the application of the treatments and soybean sowing in 2016, and will be again sampled in 2017, 2018 and 2019. The soil solution will be collected by means of porous capsule extractors for analysis and ionic speciation of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, chlorine, boron, manganese, fluorine, iron, copper and zinc, in addition to pH determination. The distribution of the root system of the crops in the soil profile will be evaluated. The contribution and persistence of straw on the soil will be evaluated periodically by determining the mass and the contents of 15N of the dry vegetable residues and also the contents of N. The results will be submitted to analysis of variance, t test, correlation and regression polynomial.
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