The effect of organic and chemical fertilizers on the activity of soil enzymes in soils of different compositions

In this study, the effects of chemical (20:20:0 compound) and organic (barnyard) fertilizers applied to different textured soils on several soil enzyme (urease, acid phosphatase, alkaline phosphatase, and dehydrogenase) activities were investigated. The research was conducted under greenhouse conditions with (beans and corn) and without crops. Considering the results of the preexperiment analysis of the soils, a 40-g pot–1 of farmyard manure was placed into the pots in which organic fertilizer would be applied in clay and silty loam soils, and a 50-g pot–1 of farmyard manure was added to sandy loam soil; in addition, a 0.25-g pot–1 of 20:20:0 compound fertilizer was mixed into the clay, silty, and sandy loam samples where chemical fertilizer would be applied. Soil chemical properties such as soil reaction (pH), electrical conductivity, lime, organic matter, useful phosphorus, total nitrogen, exchangeable cations (Ca, Mg, Na, K), cation exchange capacity, microelements (Fe, Cu, Mn, Zn), and soil enzymes (urease, acid phosphatase, alkaline phosphatase, and dehydrogenase) were determined. According to the results, fertilizers applied to the soil increased the soil's pH, organic matter, and macro and micronutrient contents and decreased the exchangeable Na content. The lime content of the soils did not show any decrease or increase. Organic and chemical fertilizers applied to the soil increased the activity of soil enzymes (urease, acid phosphatase, alkaline phosphatase, and dehydrogenase).