The present research project is part of a long-term experiment, installed in 2002/03, at the College of Agricultural Sciences of UNESP, in Botucatu (SP). Since the implantation, the persistence and distribution of 15N within the soil-corn / forage-soybean system and the activity and microbial population in relation to the soil N cycle have never been evaluated. Thus, following the experiment, which should probably be the only one in the State of São Paulo with more than 16 years of evaluation, the objective of the present study is to evaluate the effect of surface application of limes and gypsum in long-term on the chemical, physical and biological soil attributes, root growth, plant nutrition and yield of maize intercropped with Urochloa ruziziensis and soybean in succession, as well as the efficiency of the use of N- (15NH4) 2SO4 in the soil-plant system . The field part of the present proposal has been conducted since October 2016, when the limestone and / or gypsum doses were last applied. The soybean sowings occurred in December 2016 and November 2017 and the maize intercropped with Urochloa ruziziensis was sowing in April 2017 and March 2018. This crop sequence will be carried out during the 2016/17, 2017/18 , 2018/19, 2019/20. The experimental design will be in randomized blocks in the subdivided plots scheme, with 4 replicates. The plots consist of four levels of lime (no application, 3,260, 6,520 and 13,040 kg ha-1) and the two-level plots of agricultural gypsum (no application and 10,000 kg ha-1). The following evaluations will be carried out: mineral nutrition, grain yield of crops, root growth of the crops, 15N recuperation in the soil-plant system, chemical, physical and biological attributes of the soil and fractionation of organic matter.
News published in Agência FAPESP Newsletter about the scholarship: