Monitoramento da salinidade de um latossolo cultivado com maracujazeiro irrigado com água salina

Abstract

Soil salinization can occur naturally and/or anthropically, with irrigation being one of the main agricultural practices due to the increase in soil salinity levels in semiarid regions. Therefore, the spatio-temporal assessment of soil salinity levels becomes essential for sustainable agricultural management. The objective of this study was to evaluate the evolution of salinity and sodicity of an Oxisol under yellow passionfruit cultivation irrigated with saline water, in the municipality of Cuité, State of Paraíba. For this, the attributes and risks of salinity and sodicity of irrigation water and soil were evaluated at depths of 0-0.20; 0.20-0.40 and 0.40-0.60 m. Monthly and for six months (september 2020 to february 2021) the following variables were determined in the water and soil collected: pH, electrical conductivity (EC), sodium adsorption ratio (SAR), percentage of sodium saturation (PSS), cation contents (Na+ , K+ , Mg2 + and Ca2+), anions (SO4 2- , Cl- , CO3 - and HCO3 - ) and total dissolved salts (TDS) (only for irrigation water). The results showed small variation in the chemical composition of water during the evaluation period, which exhibited acidic pH (<5.0), absence of carbonates and bicarbonates, high risk of salinity (C3), very high risk of sodicity (S4) and severe Cl and Na+ toxicity. In the soil, greater accumulations of Na+ and Cl- were found, mainly in the superficial layers and in the months of less precipitation (september to december); in this situations the soil was classified as saline, prevailing the non-saline character in the remaining period. It was concluded that the sustainability of agricultural production of these soils involves the rational management of soil, water and plant factors.