Densidade de semeadura de milho com base em zonas de manejo

Abstract

Precision agriculture techniques help the producer in making the management decision to be used in the crop, in order to increase profitability. Decisions are based on the spatial variability existing in the soil, therefore requiring it to be mapped. The apparent electrical conductivity of the soil (ECa) is a potential tool for mapping the spatial variability of the soil, serving as a basis for delimiting management zones (ZM), enabling the adoption of different managements in each ZM, thus optimizing the use of inputs and providing a more sustainable farm. This study aimed to analyze the productive behavior of the corn crop, cultivated at different population densities, in delimited management zones based on the mapping of the spatial variability of the ECa. The study was conducted on a rural property in the municipality of Cachoeira do Sul during the 2021/2022 harvest. The ECa of the soil was measured and two ZM were subsequently delimited, one with low and one with high ECa. In each ZM, four maize sowing densities were tested, namely: 60,000 (D1), 80,000 (D2), 100,000 (D3) and 140,000 (D4) seeds ha-1 . The following variables were evaluated: ear length, number of grains per ear, number of grains per row, number of rows per ear, thousand-grain weight and yield. The apparent electrical conductivity of the soil showed spatial variability in the studied area, allowing the delimitation of two management zones. The increase in sowing density, in the management zone of high apparent electrical conductivity of the soil, linearly reduced the values of ear diameter, number of rows per ear, number of grains per ear and thousand grain weight. Sowing density 3, equivalent to 100,000 seeds ha-1 , when implanted in the management zone of low apparent electrical conductivity of the soil, showed higher values for the variables ear length, ear diameter, number of grains per row, number of grains per ear and thousand-grain weight. Sowing density 2, equivalent to 80,000 seeds ha-1 , was the one that presented the highest corn productivity, regardless of the management zone where it was implanted, obtaining a productivity of 5,628.48 kg ha-1 in the high conductivity management zone soil apparent electrical conductivity and 4,463.63 kg ha-1 in the management zone of low apparent soil electrical conductivity.