关键词: 密云水库, 板栗林, 养分元素, 生物循环

Abstract: Field experiments were carried out on Loess Plateau to investigate the effects of cropping on the physical and chemical properties, phosphatase activity, and N₂O emission of upland soils. The results showed that planting winter wheat could increase soil N₂O emission, regardless of fertilization or mulching. The N₂O flux was higher in wheat field than in fallowed field, and decreased in the order of film-mulching＞routine treatment＞single phosphorus fertilization. In conventionally tilled and film-mulched treatments, soil water content was lower in wheat field than in fallowed field, while NH₄⁺-N content was in adverse. Multiple regression analysis indicated that the difference of N₂O flux between wheat field and fallowed field was negatively correlated to the increment of soil organic matter, and the amount of energy material was the key factor determining the changes of soil N₂O emission. There was a significant negative correlation between soil phosphatase activity and N₂O emission, and thus, it’s of significance for the phosphorus-deficient soil on Loess Plateau to increase its phosphatase activity to mitigate the N₂O emission.

Key words: Miyun reservoir, Castanea mollissima B1 forest, Nutrient elements, Bio-cycling