Enzyme activities in a preluvosoil as affected by crop rotation and fertilization systems

Abstract

A major agricultural research priority has been recently focused on sustaining soil health and quality, and identifying key parameters or processes for monitoring changes in soil properties induced by agricultural management practices. Enzymatic activities are sensors of soil stress to management practice that may sensitively warn us about soil degradation. In the present study, three key soil enzymes involved in intracellular metabolism of microorganisms and two soil enzymes involved in phosphorus metabolism were selected. Actual and potential dehydrogenase, catalase, acid and alkaline phosphatase activities were determined in the 0–20 cm layer of a preluvosoil submitted to a complex crop rotation and fertilization experiment at the Agricultural Research and Development Station in Oradea (Bihor County). The soil under all crops was more enzyme-active in the 4-than in the other rotations or in the monoculture. In the 2-crop rotation, higher enzymatic activities were registered under maize than under wheat, only in the case of dehydrogenase activity. In the plots of the 3-and 4-crops rotations the enzymatic indicators of soil quality varied, depending on the nature of crops and kind of fertilizers. Additions of fertilizers increased the soil enzymatic activities because of an increased plant biomass production, which upon incorporation stimulates soil biological activity. It should be emphasized that farmyard-manuring of crops, in comparison with the mineral fertilization led to a significant increase in each of the five enzymatic activities determined.