Anderson Lange

Sulfato de amônio e uréia em cobertura no milho em semeadura direta no Cerrado

Timing and sources of sidedress nitrogen on no-tillage corn two years after soy crop N application to corn both at planting and preplant can optimize farm work. The aim of this study was to evaluate the effect of split supplemental nitrogen applications on leaf N content and corn yield, two years after soybean crop, in a sandy clay loam soil and quantify N recovery using isotopic dilution ( 15 N). The treatments consisted of 110 kg ha 1 nitrogen applied at different times: at planting; 5 days preplant; sidedress (5-7 leaves); and sidedress (9-10 leaves). Difference was found for corn yield and leaf content of N, phosphorus, calcium and sulphur when supplemental nitrogen was applied after planting in different times compared with no supplemental application. Split application of 110 kg ha -1 N between preplant and sidedress or sidedress only did not affect total N recovery. The recovery of nitrogen from sidedress ammonium sulfate was higher than from urea. Split of sidedress ammonium sulfate led to higher N recovery than a single application.

Atributos físico-hídricos do solo em sistema integrado de produção com diferentes arranjos do componente florestal paricá

The objective of this work was to compare the structural quality and water retention curve of a Haplustox under single, double, and triple “paricá” (Ochroma pyramidale) lines in an integrated production system at 50 months of implantation. Soil was collected from five sampling points considering the distances from the tree lines. Undisturbed samples were collected from the 0.00–0.10 and 0.10–0.20-m layers in order to assess porosity, density, soil penetration resistance, soil water retention curve, and the “S” index. The forest arrangement based on three paricá lines promoted better soil physical conditions than the system using single lines. The main changes were recorded in the 0.10–0.20-m layer, with increased microporosity and decreased cryptoporosity and resistance to penetration. The arrangements using single and double paricá lines result in higher volume of available water and greater soil compaction.