不同坡度下蔗地土壤侵蚀及氮素流失对雨型和甘蔗生育期的响应.

[Objective] The aims of this study are to explore the influence of slope, rainfall pattern and sugarcane growth period on soil erosion and nutrient loss on slope surface, and to provide theoretical basis for the mechanism improvement and prevention of soil erosion in sugarcane planting area of lateritic soil. [Methods] In-situ observation method in runoff area was used to explore the characteristics of soil erosion and loss of nitrogen nutrients (nitrate nitrogen and ammonium nitrogen) at different slopes (5° and 10°) under different rain types and sugarcane growth period. [Results] (1) The runoff in each growth period decreased in the order; extension period tillering periodseedling period mature period, and the nitrogen loss in tillering period was significantly higher than that in the other three periods (2.6~905.2 times). The sediment yield and their nitrogen nutrient loss followed the order: tillering stage extension period seedling period maturity period, the sediment yield of sugarcane in the tillering stage was significantly higher than that in other periods (2.9~71.4 times), and the difference was more obvious under the 10° slope. (2) Type B (medium rainfall depth, short duration, strong rainfall intensity) and type C (great rainfall depth, short duration, extremely strong rainfall intensity) were the main rainfall pattern that caused soil erosion and the nitrogen nutrient loss in sugarcane in the research area, contributing more than 70% of the slope runoff, sediment yield and nitrogen loss. In different slope treatments, there were significant differences in the sediment amount under type C, sediment ammonium nitrogen loss under type A and runoff ammonium loss under type B. (3) Rain pattern and sugarcane growth period had significant effects on runoff, sediment and those nitrogen loss on sugarcane slope (p<0.01), and the effect was higher than that of slope, interaction between slope and rain pattern, interaction between slope and growth period. Compared with runoff and those nitrogen loss, slope and its interaction with rain pattern and growth period showed more prominent effects on erosion sediment and nitrogen loss. [Conclusion] The slope had a more significant influence on the sediment and nitrogen nutrient loss process of sugarcane slope. The soil erosion and nitrogen nutrient loss were greatest in the tillering period, mainly contributed by type B and type C. [ABSTRACT FROM AUTHOR]