金沙江干热河谷新银合欢人工林枯落物层持水特性研究

通过对金沙江干热河谷新银合欢人工林内枯落物层持水特性的试验研究,总结出林内枯落物层的持水特性。结果表明,新银合欢林内枯落物全年凋落总量为7.03 t/hm2,月平均为0.59 t/hm2,枯落物层的厚度为2.14.5cm,其中12月凋落最盛。枯落物的自然含水量月平均为25.27%,最大月出现在8月,与该区域的降水有较好的拟合关系,但存在滞后效应。持水速率在0.5 h内迅速增大,在浸泡48 h后基本达到最大值,在0.5 h内林内枯落物可以吸收1.2 mm的降水,当降水<11.72 mm时新银合欢林内不会产生径流。饱和持水率变化范围在66.94%-182.86%,最大持水量为自重的2倍以上,自然含水量与饱和持水率的关系在雨季呈正相关,而在旱季相关关系不明显。

Study on Litter Water Retaining Capacity of Leucaena Leucocephal Plantation in Jinsha River Hot and Dry Valley

Through the experiment of Leucaena leucocephal forest litter water-holding characteristics in Jinsha river hot and dry valley, the litter water retaining capacity was studied . The results showed that the annual litter fall was 7.03 t/hm^2 and the monthly average of litter fall was 0. 59 t/hm^2 ,the litter thickness was 2.1-4.5 cm. The maximum of monthly litter fall occurred in December. The monthly mean of water content was 25. 27%, the maximum of monthly occurred in August, water content and amount of precipitation in this area varied in the same pattern, but it expressed lag effect. Speed of water content rapidly increased within 0. 5 hour, it reached the maximum of water-holding capacity after 4- 8 hours. The water-holding capacity equal to 1.2 mm precipitation within 0. 5 hour, the forest region will not occurred surface runoff if the amount of precipitation under 11.72 mm. Saturation content rate of litter varied from 66.94%-182.86%, the maximum of water-holding content was over two times than itself weight. The relation of water content and saturation content rate varied in the same pattern in the dry season, but it was not obvious in the rainy season.