1.The Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education;2.Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
坡耕地养分流失可导致土地退化，引起非点源污染。降解地膜既具有普通地膜优点，又易于降解，被广泛用于耕地种植，但其对养分流失的影响机理尚不清楚。为探究降解地膜覆盖对径流及溶解态氮磷流失的影响，利用野外原位径流小区，以覆膜垄作花生种植为研究对象，设置0.003 mm厚聚乙烯普通地膜覆盖处理（PF）和厚度为0.006 mm（BF1）、0.008 mm（BF2）、0.010 mm（BF3）、0.012 mm（BF4）的降解地膜覆盖处理，及未覆膜处理（CK），测定不同处理在自然降雨条件下的径流量及径流中铵态氮（NH4+-N）、硝态氮（NO3－-N）、速效磷（PO43－-P）浓度，分析不同厚度降解地膜覆盖条件下径流及养分流失特征。结果表明：（1）降解地膜降解所需时间随地膜厚度的增加而增加。（2）各处理的累积径流量由小到大为BF1＜BF2＜BF3＜PF＜CK＜BF4，BF1与BF4之间差异显著（P＜0.05）。（3）与CK相比，各覆膜处理均能不同程度减少氮磷累积流失量。其中，BF1处理对NH4+-N、NO3－-N流失量的削减效果较好，而BF2处理对PO43－-P流失量的削减效果较好。（4）在五个覆膜处理中，BF4处理的NO3－-N、PO43－-P流失量最高，而BF3处理的NH4+-N流失量最高。研究结果可为防治覆膜坡耕地水土及养分流失、解决农业面源污染等问题提供理论基础，对绿色农业发展和生态可持续发展具有重要意义。
Soil nutrient loss of slope farmland can lead to land degradation and non-point source pollution. Degradable mulch film not only has the advantages of polyethylene mulch film, but also is easy to degrade, and is widely used in cultivated land planting. However, the mechanism of its effect on soil nutrient loss is still unclear. To explore the effects of degradable mulch film mulching on runoff and loss of dissolved nitrogen and phosphorus, polyethylene film mulching (PF) with a thickness of 0.003 mm, degradable film mulching with a thickness of 0.006 mm (BF1), 0.008 mm (BF2), 0.010 mm (BF3) and 0.012 mm (BF4), and no mulch (CK) were set up. In in-situ runoff plots, using mulching on ridge tillage peanut planting as the study object, the runoff and concentration of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3－-N), and available phosphorus (PO43－-P) in runoff under natural rainfall conditions were measured, and the runoff and nutrient loss characteristics under different thickness of degradable mulch film were analyzed. The results showed that: (1) The degradation time of degradable film increased with the increase of film thickness. (2) The order of cumulative runoff was BF1＜BF2＜BF3＜PF＜CK＜BF4, and there was significant difference between BF1 and BF4 (P<0.05). (3) Compared with CK, different film mulching can reduce the cumulative loss of nitrogen and phosphorus to varying degrees. BF1 had the most significant effect on reducing the loss of NH4+-N and NO3－-N, while BF2 had the most significant effect on reducing the loss of PO43－-P. (4)The loss of NO3－-N and PO43－-P in BF4 was higher than that in other mulches, while the loss of NH4+-N in BF3 was higher than that in other mulches. The results can provide a theoretical basis for the prevention and control of water, soil, and nutrient loss in sloping farmland mulching with plastic film and solving the problems of agricultural non-point source pollution, which is of great importance for the development of green agriculture and sustainable ecological.