Chemical Soil Attributes in a Rotating System under Salinity and Nitrogen Trials

Abstract

Inadequate soil management promotes changes in soil chemical attributes and, consequently, soil fertility. Therefore, the chemical attributes of the soil under crop rotation system sunflower (Helianthus annuus)/maize (Zea mays) during 24 months in intercropping were studied, cultivating sunflower in the dry period and maize in the rainy season. A multivariate analysis was used to evaluate the behavior of soil chemical variables in the rotational system with different water salinity levels (0.8, 2.2, 3.6, 5.0 and 6.4 dS m-1), nitrogen doses (0, 50, 100 and 150% of the recommended dose of N, corresponding to 0, 25, 50 and 75 kg N ha-1, respectively), analyzing the data of the stations in a single depth (0 - 0.30 m). The variables used were: pH, electrical conductivity of soil saturation paste extract, calcium, magnesium, sodium, potassium, phosphorus, potential acidity, exchangeable sodium percentage, base sum, cation exchange capacity, base saturation, saturation by Aluminum, organic carbon and organic matter. By the multivariate analysis, we verified that crop rotation along with supplementary irrigation and precipitation in the rainy season ameliorated the effects of salinity along with the use of nitrogen. It was concluded that it is possible for the soil to have good cultivation conditions even in saline environments, using crop rotation and leaching of the salts in the rainy season by means of rainfall.