Spatial analysis of soil micronutrients in an area of extensive pasture in the southeast of the State of Tocantins

Abstract

The use of geostatistical tools in Precision Agriculture allows for the identification of heterogeneous zones, contributing to soil and crop management, production costs, and potential environmental is The variability of micronutrients in the soil is influenced by geology, biological factors and anthropogenic factors that can affect the lack or excess of these in the soil, which despite being required in smaller quantities are essential for plant development. The aim of this study was to assess the spatial behaviour of micronutrients in an extensive pasture area in the southeast of the state of Tocantins. The experiment was conducted at the Federal Institute of Tocantins, Dianópolis Campus, Animal Production Sector, located in the municipality of Dianópolis (TO). The soil evaluated was classified as dystrophic Haplic Cambisol and has a history of extensive pasture for more than 10 years. Soil samples were collected manually at a number of georeferenced sampling points (25x25m) within the study area (approximately 2 ha), totalling 30 composite samples, at a depth of 0-20 cm. Clay, pH, OM and micronutrient levels were analyzed from each soil sample: boron (B), iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn), and the data was subjected to analysis geospatial by software Surfer. The variability of the attributes classified according to their coefficient of variation (CV) showed high values (CV>60%) for Fe, Mn and Zn, medium values (15-60%) for Clay, OM, B and Cu and low values (<15%) for pH. Therefore, the attributes researched presented a low to high degree of spatial dependence. However, it was possible to map the chemical attributes of the soil, where the greatest variability was observed for the micronutrients Zn, Mn and Fe. sues. This study aims to evaluate the spatial variability and relationship between micronutrients in a fallow area in the southeastern state of Tocantins. The experiment was conducted at the Federal Institute of Tocantins, Campus Dianópolis, Animal Production Sector, located in the municipality of Dianópolis (TO). The soil evaluated was classified as dystrophic Haplic Cambisol and has a history of native pasture for over 10 years. The soil chemical attributes evaluated were clay, sand, silt, pH, and micronutrient contents: boron (B), iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn). The contents of clay, boron, copper, and iron showed low spatial variability, while Mn levels were classified as moderate and Zn as high variability. However, it is important to note that observed levels of Cu, Fe, Mn, and Zn micronutrients were above the critical limit (<0.2; <4.5; <2.5; and <0.6, respectively). The pH and clay content attributes are correlated and influence the availability and spatial distribution of micronutrients.

Keywords

• Variability
• Nutrients
• Soil