有无枯落物覆盖对加勒比松林地表径流及其K流失的影响

为了解有无枯落物对K随地表径流损失的影响,研究比较了有无枯落物加勒比松林地表径流中的K流失的特点,结果表明:有、无枯落物加勒比松林的年地表径流量分别为12.6、51.8 mm,主要发生在夏季,对应的地表径流系数分别为0.60%、2.48%,表明前者能有效削弱地表径流。2种林分的降水量和地表径流量的关系可用二项式方程表示。有、无枯落物加勒比松林各月的地表径流K浓度分别为3.2~36.3、1.8~6.0 mg.kg-1,通过地表径流输出的K量分别为701、982 g.hm-2。2008年5、6月为有枯落物加勒比松林的K流失高峰,6月为无枯落物加勒比松林的K流失高峰。地表径流的K浓度和径流量之间存在对数关系,K的流失量主要由径流量决定。

Effect of Litterfall Cover on Runoff and Potassium Loss in Pinus caribaea Stands

Potassium loss characteristics in runoff in Pinus caribaea stands with and without litterfall cover in Foshan were studied to understand the effect of litterfall on K loss of runoff. Annual runoff amounts of P.caribaea stands with and without litterfall cover were 12.6 mm and 51.8 mm, respectively, occurring mainly in summer. Runoff coefficients of P.caribaea stands with and without litterfall cover were 0.60% and 2.48%, respectively, indicating the former was good at reducing runoff. The relationship between rainfall and runoff could be expressed using a binomial equation. Monthly K concentration of P.caribaea stand with litterfall cover ranged from 3.2 to 36.3 mg·kg^-1, whereas that of P.caribaea stand without litterfall cover ranged from 1.8 to 6.0 mg·kg^-1. Annual K losses of P.caribaea stands with and without litterfall cover were 701 and 982 g·hm^-2, respectively. A distinct seasonal pattern of K loss was observed at May and June, 2008 for P.caribaea stand with litterfall cover and at June, 2008 for P.caribaea stand without litterfall cover. Annual K losses were mainly decided by the amount of runoff. A logarithmic relationship existed between K concentration in runoff and the runoff.