Soil fertility in the Central-southern part of Romania expressed by soil reaction and nutrient content: a case study from the Raul Alb catchment, Dambovita County

Abstract

The field research took place between 2019 and 2020, in the upper river basin of the Raul Alb creek, located in the northwest of Dambovita County, the analysed land area being 4034 ha. Underlying the research of the complex erosion phenomena faced by the analysed territory was the soil survey, which consisted of sampling 46 soil profiles in the representative areas for the analysed territory. For the analysis of the soil fertility, chemical analyses were performed regarding the pH, humus content, reported to the soil texture in the topsoil and the supply of nutrients (nitrogen, phosphorus and potassium), also physical-mechanical analysis (soil texture), interpreted according to the “Methodology for the Development of Pedological Studies, Volumes I, II, III, 1987”. By centralising the obtained results, it found that 59.42% of the total analysed land surface had a weak alkaline pH, at least in the topsoil, due to the CaCO3 content. For the supply of humus, the most significant share is that of the extremely low-supplied soils with this element in the topsoil, i.e. 73.42% of the mapped area, and in terms of the nitrogen supply, 26.67% of the total surface of the river basin shows severe deficiencies in this element. The situation is worrying indeed in the case of the supply of soils with mobile phosphorus, with 3 280.27 ha of the mapped surface having very low or low contents of this element, making up 81.31%. However, for potassium, the soils from the upper sector of the Raul Alb catchment are mostly moderately and well supplied, with only 620.85 ha (15.39%) being extremely poorly supplied with this element.