Effects of land use type on soil nutrient elements in the agro-pastoral ecotone of north China: A case study in Zhangbei County

Four main land use types including dry land, irrigable land, grassland and forestland in the agriculture-pasture ecotone of north China were taken as research objects. The contents of soil organic matter, nitrogen, phosphorus, potassium, available iron, available manganese, available copper, and available zinc in 0 – 15 and 15 – 30 cm soil layers were systematically analyzed. The results showed that: 1) Irrigated land showed the highest soil organic matter, total nitrogen, total phosphorus and available potassium compared with grassland, forest land, and dry land, with values of 43.42, 2.62, 2.86 and 444.00 g·kg^–1, respectively. 2) The effect of land use types varied between different trace elements, but the contents of the available iron, available manganese, available copper, and available zinc in the irrigated soil were all higher in all the four land use types, reaching up to 11.45, 15.21, 0.59 and 2.04 mg·kg^–1, respectively. 3) Soil nutrient content had a significant correlation with soil particle composition, pH, and other basic physi-chemical properties. In summary, the influences of land use type on soil nutrients were significant, nutrient contents were higher in irrigable land soil due to high water and fertilizer input. These results will provide a theoretical basis for the scientific management of soil nutrients and sustainable use of land resources.