JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (6): 1296-1305.doi: 10.31497/zrzyxb.20190614

• Resource Evaluation • Previous Articles     Next Articles

Effect of management intensity on runoff losses of nitrogen and phosphorus in bamboo forests in Zhejiang province

Rong-jie LU1,2,3(), Ying WANG1,2,3, Jia-sen WU1,2,3, Pei-kun JIANG1,2,3()   

  1. 1. State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Lin'an 311300, Zhejiang, China;
    2. Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-efficiency Utilization, Lin'an 311300, Zhejiang, China
    3. School of Environmental and Resource Sciences, Zhejiang A & F University, Lin'an 311300, Zhejiang, China;
  • Received:2019-01-04 Revised:2019-04-03 Online:2019-06-20 Published:2019-06-20

Abstract:

To determine the effect of management intensity on runoff nutrient losses in bamboo forests under natural rainfall conditions, separate field observation stations were set up at the mouths of each field-sized catchment (micro-watershed) in extensively or intensively managed areas, at Qingshan Bamboo Orchard in Lin'an district, Hangzhou city, Zhejiang province. After every successive rainfall during the year, runoff volumes were measured, and water samples from the sand-settling tanks at the observation stations were collected and analyzed for total nitrogen (TN), total phosphorus (TP), nitrate nitrogen (NO3--N), ammonium nitrogen (NH4+-N), and phosphate (PO43-) contents. Simultaneously, soil samples were also collected and analyzed for pH, organic matter, effective nitrogen and available phosphorus contents. The results showed that: (1) Annual runoffs from intensively managed and extensively managed bamboo forests were 8086.52 m3/hm2 and 4850.95 m3/hm2, respectively; (2) Nitrogen loss in runoff from the bamboo forests was dominated by nitrate nitrogen; (3) Intensive management increased the risk of nutrient losses from the bamboo forests; the annual losses of nitrogen and phosphorus from intensively managed areas were 45.26 kg/hm2 and 25.05 kg/hm2, respectively; but they were only 0.31 kg/hm2 and 0.21 kg/hm2, respectively, from extensively managed area. Compared with losses from extensively managed area, the losses of nitrogen and phosphorus from intensively managed area increased by 80.68% and 47.62%, respectively; (4) The TN content in runoff water had a significant negative correlation with alkali-hydrolyzed nitrogen content of the soil, while the TP content in runoff water had a significant positive correlation with soil available phosphorus.

Key words: soil erosion, surface runoff, bamboo forest, soil nutrient, nutrient loss, management intensity