Distribuição espacial de plantas na fileira e sua relação com a produtividade da cultura do milho

Abstract

Decreased variability in the distribution of plants on line and increased nitrogen fertilization efficiency are important order management for high yields in corn. The objective of this study was to evaluate the quality of sowing provided by two types of planting the spatial arrangement of plants and quantify the effect of spacing error between plants in plant vigor and productivity of maize and also the efficient use of dose nitrogen variable (DVN) in the different cultivation systems. The study was conducted in Carazinho-RS in the agricultural years 2012/13 (Experiment I) and 2013/14 (Experiment II) with the treatments: a) mechanical seeder feeder with horizontal discs (SM); b) air seeder and seeds organizer (SP); c) air seeder and seeds organizer coupled to tractor with autopilot and RTK signal (SPP). The study was conducted in macro plots of 6,600 and 990m2 for the experiments I and II respectively and in micro plots for the study plant to plant with plots of 5.4 m2. Still, a case study was directed in the form of transects of 5 plants which investigated the effect of spacing error between plants vigor and productivity of the crop. The evaluation of DVN efficiency was held in Experiment II area, the main tracks for cultivation systems, the DVN and the fixed dose of nitrogen (DFN) divided into the main tracks. The sowing quality was affected by the type of seed feeder and had no effect on the use of the autopilot, and the best distribution obtained in treating SP, with a CV of 25.4 and 19.7% for the experiments I and II respectively. The best spatial arrangement of plants in the SP in relation to MS, with a reduction of approximately 16% in the CV spacing between plants in both experiments in the macro share resulted in an increase of 12.5 and 6.8% in productivity, respectively. Furthermore, the use of autopilot and RTK signal (SPP) increased by 7% relative to the productivity SP in the first experiment. In the study of micro plots, which was evaluating the individual productivity of plants in the planting line, the SP there was only 2% of plants with lower productivity at 8,500 kg ha-1 for the first trial and 10% below 6500 kg ha-1 to II. Already, in the SM the frequency of plants below these productivity was approximately 18% in both experiments, and these results attributed to higher occurrence of dominated plants, which was justified in force assessments plant by NDVI through the uniformity of assessment and of the highest rates in the SP relative to the SM. In the study of DVN in Experiment II, the negative effect that has an unusual distribution of plants was minimized by DVN, however when associated with a more uniform distribution of plants in an environment with greater productive capacity, even in a year with restrictions water productivity is enhanced. In the investigation of error in the distribution of plants through the case study, it was found that the NDVI indices and grain yield are negatively affected for every 10% increase in CV, and the decrease in productivity of 1,356 and 815 kg ha -1 for experiment I and II, respectively, demonstrating the importance of the distribution of the plants near the equidistance lines.