Módulo computacional para delineamento de mapas de aplicação de calcário a partir dos atributos químicos do solo

Abstract

With the growth of the world population, Brazilian and world agriculture have the challenge of producing more, with greater profitability and competitiveness. Considering that about 30% of the total area of the planet consists of acid soils and 50% of these are arable, this could mean serious limitation for agricultural production in many regions of the world. In this sense, precision agriculture is one of the technologies adopted in the modernization processes of agriculture, and consists of a set of technologies for the localized application of the correct quantity of the production inputs, at the right time, in the right place, based on the topography and spatial variability soil and cultural attributes. Therefore, the recommendation of agricultural inputs in the necessary quantity, without compromising the productivity of the crops, becomes an important tool for the farmer and consequently, the appropriate recommendation of limestone. In order to perform this practice rationally, it is necessary to establish the appropriate quantity of limestone for the agricultural operation, based on the chemical and physical attributes of the soil. Liming will neutralize acidity, raise pH, reduce toxic elements and increase polyvalent cations. Thus, the objective of this work was to develop a computational module (AgDataBox-Map-Aplic) capable of recommending the amount of limestone considering the chemical attributes of the soil of each sampling point. For this, the following methods of calculating the required limestone were selected: Method 1: neutralization of exchangeable aluminum; Method 2: exchangeable Al3+ neutralization and elevation of base cations (Ca2+ and Mg2+); and Method 3: base saturation. The modeling of the system was in UML diagrams (Unified modeling language), in order to specify in detail its functionalities. To evaluate the module, two traditional techniques were compared (Traditional Thematic Map (TTM) and management zones (MZs)) for the construction of the thematic map of localized limestone application with data from three commercial agricultural areas (western Paraná State, Brazil) and three calculation methods of limestone requirement. The lowest mean amounts of limestone (𝑄𝐶̅̅̅̅) were always obtained by application in MZs, with doses calculated by the median. In the evaluation of the quality of the ZMs, the indexes VR, FPI, MPE, ICVI, SI% and IF% were used; in the consonance comparison between TTM and MZs, K, T and EG indexes. The outlining with two classes presented the best results. The results obtained by means of the ADB-Map- Applications presented a high correlation (R2 of 0.99) compared to the values observed in spreadsheet.