Recovery efficiency of nitrogen and grain yield according application of sulphur at the base or in side dress of corn

• Grant number: 14/04672-6
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2014
• End date: June 30, 2015
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Waldo Alejandro Ruben Lara Cabezas
• Grantee: Waldo Alejandro Ruben Lara Cabezas
• Host Institution: APTA Regional. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

Interaction between nitrogen (N) and sulfur (S) is determinant for the quantity and quality of the protein in food production. This study aims to determine whether the combined application of N and S is more efficient in N recovery by the plant when applied together on the side dress (stage 3-4 leaves expanded) in relation to deferred application of S and N in the base and side dress, respectively. At sowing will use rates of 40 kg ha-1, 80 kg ha-1 and 60 kg ha-1 based on N, P2O5 and K2O, respectively, and rates of 120 kg ha-1 of N topdressing. To maintain the constant amount of S for all treatments (53 kg ha-1 S) will be used super simples phosphate (SSP) and at the side dress ammonium sulfate (AS) supplemented with urea (U) to satisfy the dosage N defined. In seasons 2014/2015 and 2015/2016 trials will be in ortho Oxisol (LE) in a randomized block design with four treatments, with four replications. The treatments are: a) without application of S at the base or top dressing; b) with exclusive application of S at base; c) exclusive application of S at side dress and d) with split rate of S application in the base and side dress. In three of the four replicates of each treatment will be install micro plots using 15N-urea, 15N-34S-ammonium sulfate and 34S-supersimples phosphate, in order to quantify in shoots and grains the absorption of these nutrients in the two sampling periods: stadium of 12-14 leaves and physiological maturity and correlate the results with grain yield. At these same times will be sampled each soil layers (0-20 cm and 20-40 cm) for the determination of total mineral-N and sulfate-S. Evaluation of distribution and dry matter of roots with time of harvest will be in all treatments. (AU)