Mapping the Available Water Capacity in tropical climate soils for soybean (Glycine max) cultivation in the state of Tocantins-Brazil

  • André de Moura Andrade Mestrado em Agroenergia. Universidade Federal do Tocantins (UFT), Avenida NS 15, Quadra 109 Norte, CEP: 77001-090, ALCNO-14, Bloco Bala II, Plano Diretor Norte, Palmas, TO, Brazil.
  • Rui da Silva Andrade Departamento de Engenharia Ambiental. Universidade Federal do Tocantins (UFT), Avenida NS 15, Quadra 109 Norte, CEP: 77001-090, ALCNO-14, Bloco Bala II, Plano Diretor Norte, Palmas, TO, Brazil.
  • Erich Collicchio Programa de Pós-Graduação em Agroenergia. Universidade Federal do Tocantins (UFT), Avenida NS 15, Quadra 109 Norte, CEP: 77001-090, ALCNO-14, Bloco Bala II, Plano Diretor Norte, Palmas, TO, Brazil.
Keywords: available water capacity, conservation units, pedotransfer.

Abstract

Brazilian soybean has undergone considerable economic growth. Its production depends on the demand for some inputs. One of these inputs is the soil water supply, which can be made artificially or obtained by natural rainfall. Knowledge of available water capacity (AWC), which depends on total water availability (TWA), is poorly accessible and difficult to measure in the field. This study aimed to map the AWC of the state of Tocantins, based on pedotransfer functions (PTFs), to evaluate the water availability of the soils of the microregions of that state. We used the Arya and Paris model, aided by a computer program, Qualisolo, made by Embrapa Instrumentação. One hundred fifty-seven tropical soil samples were extracted from the Embrapa Solos portal. Preliminarily, the soil water retention curve (SWRC) was obtained and, subsequently, the TWA and AWC for this oilseed were estimated. Multiple linear regressions show the correlation between TWA and clay (CL), Silt (ST) and total sand (TS) contents. The correlation established was TWA = 3.2993 – 0.0028TS – 0.0034CL. This main conclusion reflects a fruitful AWC for decision-making by the soybean agribusiness and exposes the regional weaknesses for this crop under a rainfed regime in some regions of Tocantins. We could observe that, in terms of water availability, agribusiness is a potential threat to the environment protection area (APA) of the Ilha do Bananal/Cantão, Formoso River microregion.


Published
22/09/2021
Section
Papers