Effects of Tree Species and Soil Enzyme Activities on Soil Nutrients in Dryland Plantations

Long-term afforestation strongly changes the soil’s physicochemical and biological properties. However, underlying mechanism of different tree species driving change in soil nutrients is still unclear long-term dryland plantations Loess Plateau, China. In this study, samples surface (0–20 cm) woody litter were collected from five (?50 years) Caragana korshinskii, Armeniaca sibirica, Populus hopeiensis, Platycladus orientalis, Pinus tabulaeformis a natural grassland, tested for carbon, nitrogen, phosphorus, potassium contents, as well sucrase (SC), urease (UE), alkaline phosphorus (ALP) activities. We found that nutrients, enzyme activities, litter’s chemical properties obviously varied among species. C. korshinskii significantly increased TC, organic carbon (OC), total nitrogen (TN), available (AN), (AK) by 28.42%, 56.08%, 57.41%, 107.25%, 10.29%, respectively, also (AP) 18.56%; while P. orientalis decreased TN (38.89%), TP (30.58%), AP (76.39%), TK (8.25%), AK (8.33%), OC (18.01%) AN (1.09%), compared with those grassland. The plantation had higher quality activities than plantation. Moreover, 62.2% variation was explained (LP) ALP more significant positive impact on nutrients. Therefore, species, LP, key factors nutrient succession plantations. nitrogen–phosphorus coupling relationship “litter–enzyme–soil” system revealed improving level promoted cycle ecosystem. Our results suggest leguminous are suitable through regulation