The Study On Soil And Water Conservation Of Land Utilization Pattern In Lanlingxi Small Watershed

The land-use configuration pattern on the slope scale plays a key role in soil erosion and nutrient loss.this research chose the minor watershed of Lan Ling Creek as the experimental sites. Based on the position of different land use types on the slop,there are four patterns in this experiment:Pattern:Chestnut+Broad-leaved Forest(Pattern T1), Tea+Broad-leaved Forest(Pattern T2), Sparse weed slopes+Tea Garden(Pattern T3), Chestnut+Natural Grassland(Pattern T4), Tx-1represents the up-slope land using type, Tx-2represents down-slope land using type. This research study and determine the soil physicochemical property, the characteristics of runoffs on the slopes, the pattern of soil erosion and characteristics of nutrient loss in such four typical land-use patterns. The experimental results are as follows:There exist great differences among the indexes of soil physical property in different land using patterns. Soil physical properties are obvious patches Mosaic pattern, that consistent with the configuration pattern of land use structure, form self-regulation system of the runoff erosion.There exist great differences among the nutrient distribution in different patterns, there down-slop have different degree of enrichment of nutrients. Soil nutrients are obvious patches Mosaic pattern, that consistent with the configuration pattern of land use structure. Tea garden is affected by fertilization, etc, the soil nutrient content is higher.The rainfall is closely relevant to T1, T2and T4. Chestnut+Broad-leaved Forest(Pattern T1) Tea+Broad-leaved Forest(Pattern T2) and Chestnut+Natural Grassland(Pattern T4) can effectively reduce runoff, Runoff comparison is T2>T1>T4, as to water conservation, T4ranks the first. When it rains moderately, Broad-leaved Forest TeaN Natural Grassland do much better than Chestnut and Sparse weed slopes reducing runoff among4patterns. T4is the best in reducing runoff. As the rainfall becomes the more, patterns’ability of reducing runoff becomes the weaker.The sediment erosion intensity varies greatly in different land using pattern during raining. T1’s and T2’s rate of reducing sands reaches35.2%48%, which ranks in the middle, concerning the efficiency of soil conservation; T3’s rate of reducing sands reaches9%, which is weak in conserving soil; T4’s rate of reducing sands reaches65.2%, which is strong in conserving soil. So it concludes that configuration pattern (Tx) of land use and soil conservation are the best, Compared to slope on land use types (Tx-1).The sediment erosion intensity varies greatly in different land using pattern during raining.:T3(8.1g/m2)>T1(7.49g/m2)>T2(7.41g/m2)>T4(4.54g/m2),the average value of T4’s sub-sediment erosion index ranks the bottom, far less than the loss load of T1, T2and T3, and T4’s ability of conserving soil is good.There exist great differences in runoff nutrient loss in different patterns in rainfall. The land use fertilizer conservation are the best on configuration pattern (Tx), compared to slope on land use types (Tx-1). When it rains moderately, nutrient loss of runoff loss is higher, As the rainfall becomes the more, nutrient loss of runoff reduce. Runoff and soil erosion load was significantly positively related to nutrient content.The organic matters and total nitrogen in sediment of different patterns gather, while available phosphorus and total nitrogen don’t gather well. The organic matters gather the most densely, As to T3, there are sediment erosion existing in the10rainfalls, which indicates that the soil in land without effective vegetation coverage tends to be eroded. The nutrient in the sediment and soil erosion load of nitrogen and phosphorus nutrient content are relevant.As for the capability of conserving water and soil, T4is the best pattern, while T3is the worst one with severe soil erosion. The soil fertilizer is positively correlated to the content of soil nutrient loss, the soil fertilizer in tea garden is very high and the nutrient in runoff and sediment lose severely, which is the main contributor of nutrient loss, Suppose when it rains moderately, configuration pattern (Tx) does better than Tx-1concerning water conservation and soil conservation. But Tx’s efficiency of conserving water and soil will weaken when it rains heavily.