红壤丘岗坡地土地利用与土壤水分的时空变化关系

利用连续2a土壤水分定位观测数据，对红壤丘岗坡地不同土地利用类型与土壤水分时空关系的研究结果表明：（1）生长季（3—10月）不同土地利用类型之间0—90cm深土壤平均含水量差异显著，丰水年的差异比平水年大。（2）不同水文年同一土地利用类型土壤水分季节变化差异明显。丰水年土壤水分含量较高，年内变化较平稳，土壤基本处于湿润状态；而平水年土壤水分先升高后显著降低再缓慢升高，出现明显的干湿交替。（3）从丰水年到平水年土壤水分的剖面结构类型没有发生改变，湿地松区属波动型，其他4种土地利用类型属增长型。（4）土壤水分沿坡位的年内变化始终是坡上大于坡下，持续干旱能减少土壤水分沿坡位分布的变化幅度。

Spatial and Temporal Relationship Between Land Use and Soil Moisture in Sloping-Land of Red Soil Hills

Based on two consecutive years(2002-2003) of stationary monitoring of soil moisture in red soil sloping-land,spatio-temporal relationships between land use and soil moisture were analyzed.Results show(1)the effect of land use on average soil moisture of 0-90 cm in the crop growing season varied statistically from year to year,and the soil moisture was higher in rainy year than in average year;(2)seasonal change in soil moisture under the same land use was obviously different between rainy year and average year.In the rainy year,soil moisture remained high and did not vary much through the year;while in the average year,soil moisture obviously fluctuated sharply,and stayed high in February to early July,then dropped rapidly,and finally came slowly up again;(3)when a rainy year was followed by an average year,the soil moisture variation curves did not change much.In the wetland pine zone,it was of the fluctuation type,and in the other four zones,of the increasing type;and(4) variation of soil moisture in a year was always higher in the upper slope than in the down slope.Prolonged drought reduced the amplitude of variation of soil moisture distribution along the slope.