Logística e infraestrutura da produção de soja no estado do Maranhão (Brasil): agricultura de precisão aplicada para a Sustentabilidade

Abstract

The general objective of this work is divided into two lines: a) To evaluate the logistics and infrastructure of soybean production in the State of Maranhão (Brazil); b) Map the yield of soybean (Glicine max L.) and biological, chemical and physical attributes of the soil by means of joint analyzes between geostatistics and multivariate techniques. The study area is located in the municipality of Mata Roma (Maranhão, Brazil), and has about 44.75 ha, cultivated with soybean (Glicine max L.) under a no-tillage system. A total of 70 sampling points were used to determine soybean yield (kg ha-1) and biological attributes (macrofauna and diversity indices), physical [organic carbon (g kg-1), carbon stock (Mg ha-1), hydraulic conductivity (m day-1), soil density (Mg m-3), macroporosity (m3 m-3), microporosity (m3 m- 3), total porosity (m3 m-3), total sand (g kg-1), coarse sand (g kg-1), fine sand (g kg-1), silt (g kg-1) and clay (g kg-1)] and chemicals [organic matter (OM, g dm-3), pH in CaCl2 solution, potential acidity (H+Al, mmolc dm-3), phosphorus (P, mg dm-3), potassium (K, mmolc dm-3), calcium (Ca, mmolc dm-3), magnesium (Mg, mmolc dm-3), sodium (Na, mmolc dm-3), cation exchange capacity (CTC, mmolc dm-3), base sum (SB, mmolc dm-3), percentage of saturation by bases (V%), copper (Cu, mg kg-1), iron (Fe, mg kg-1), manganese (Mn, mg kg -1) and cadmium (Cd, mg kg-1)], in layers of 0.0-0.2 m and 0.2-0.4 m in depth. Data were analyzed through descriptive statistics, geostatistics tools and multivariate techniques (PCA - principal components analysis). The logistic conditions of state agribusiness point to different situations that imply the flow of agricultural products through fragmented and disconnected modes. In all the process related to the transportation of grains, it can be perceived several environmental damages, be it of implantation, operation and maintenance of the roads. The environmental costs of transport evidences the lack of planning policies and governance regarding the use of modalities aimed at environmental preservation. The analysis of the attributes demonstrated that the use and intensity of the soil influences the edaphic fauna, reducing or eliminating specific groups. Diversity indices that are obtained from the total number of individuals, from the base 10 logarithm, or natural, or from the square root, presented behavior different from the commonly used indexes (Shannon and Simpson), and it could be considered an alternative to include them more frequently in soil fauna studies. The multiple interaction of different soil attributes, indicated different management zones in the layers of 0.0-0.2 m and 0.2-0.4 m depth. The chemical attributes analyzed showed that the area sampled presented low to medium fertility. The variographic analysis of the eigenvalue scores of the PCA showed that in both layers the semivariogram is more stable and with greater spatial dependence between the samples. The spatial variability maps of the scores of IX the eigenvalues of the principal component analysis showed that it is possible to determine management zones using PCA 1 in the two depths under study, however, with different management strategies.