板栗复合经营模式的土壤流失规律

 为探讨红壤低山丘陵区不同板栗复合经营模式内水土流失的时空变化规律,采用径流小区定位观测,对7 个模式内的土壤流失量进行连续8年的研究。结果表明:在幼林下间种、停止间种和林冠迅速生长、林分充分郁闭 3个阶段,土壤流失量出现缓慢减少、急剧减少和基本稳定的变化过程;幼林下间种的当年,各模式内土壤流失量变化22．5-31．1t/(hm2·a)之间,但小于对照32．91％-51．45％;模式经营进入第3阶段后,林地土壤流失量均在 0．05t/(hm2·a)以下;在日降雨量10—70 mm间,日降雨引起的土壤流失量差异较大,间种作物覆盖地表,对于10～ 70mm日降雨强度的土壤侵蚀力且有重要的抗蚀意义。

Law of soil loss at agro-forest ecosystem of Castanea mollissima

By means of a fixed observation station of runoff plot, soil loss amount at 7 different agro-forest ecosystems were recorded and analyzed successively for 8 years, in order to find out the space-time variation law of soil erosion at different agro-forest ecosystem of Castanea mollissima in low hilly region of red soil. The results showed that soil loss amount slowly reduction, sharply reduction and become stable occurred at the following 3 stages respectively, young intercropped Castanea mollissima forest, crown fast-growing stage without intercrop, and stand closed stage. The soil loss ranged from 2.25 t/hm² to 3.31 t/hm², but from 32.91% to 45% less than that at CK in the current year of intercropped. When the stand became closed (at the third stage), the soil loss was less than 0.05 t/hm². There were much differences of soil loss among the 10 to 70 mm rainfalls daily. Intercropped plant covering surface land is important for erosion control among the 10 to 70mm rainfall daily.