Geochemical characteristics and influencing factors of soil nutrients in cultivated land in Renhuai, Guizhou Province

This paper is the result of agricultural geochemical survey engineering.

Objective The research aimed to provide a scientific basis for the rational use of soil nutrients in agricultural production, adjustment of agricultural structure and improvement of land use value in Renhuai.

Methods Total and available nitrogen (phosphorus and potassium) content and organic matter content of 5, 486 topsoil samples were obtained using inductively coupled plasma emission spectrometry, volumetric method, and potentiometric method. Their geochemical characteristics and influencing factors were systematically studied.

Results The average values of nitrogen, phosphorus, potassium, organic matter, available nitrogen, rapidly available phosphorus, and rapidly available potassium were 1.74 g/kg, 0.75 g/kg, 19.90 g/kg, 30.90 g/kg, 100.28 mg/kg, 10.40 mg/kg, and 101.03 mg/kg, respectively. The contents and distributions of nitrogen, available nitrogen, phosphorus, potassium, and organic matter were closely related to the stratum, whereas those of rapidly available phosphorus and rapidly available potassium were not. Cultivated land in Renhuai had a relatively high soil fertility rating, which was mainly dominated by relatively rich soil grades, with the share of relatively rich and rich grades reaching 57.6%. Rich nitrogen, phosphorus, and potassium levels were found, along with medium available nitrogen and organic matter levels. However, rapidly available phosphorus and rapidly available potassium were at deficient levels.

Conclusions The content and distribution of soil nutrients in cultivated land are not only affected by natural factors such as geological background, soil type, altitude, pH, and soil depth, but also related to human activities, such as land use patterns.