Effects Of Straw Mulching And Vetiver Hedge On Runoff, Soil Erosion And Hypogaea Growth On Red Soil Sloping Land

Slope red earth refers to the red soil which developed around the weathering crust of bedrock and generally is located in mountain land and hills. Hillside red earth occupies approximately53%of the total area of red soil in our country, and has its wide distribution principally across the vast areas of14southern provinces in China. Soil loss and water erosion area in Jiangxi province amounts to21%of the national territorial area, in most cases the lost land is red soil on slopes, rather other land resources. Due to severe soil and water loss for the sake of landslide, this kind of soil is left with relatively thin soil layers, less powerful erosion resistance and in particular, the decline in soil fertility and productivity which is less favorable for the purpose of agricultural production, therefore, one significant control measure in addressing the enhancement of agricultural productivity lies in the development of the soil and water conservation technology on red soil of dryland gentle slope. Compared with the conventional water conservation pattern, biological conservation measures have the advantage of being economic, effective and sustainable. For instance, contour living hedgerow is the commonly used biological engineering measures in the preventive treatment of soil erosion of slope farmland. This study provided the control treatment, individual grass hedgerow coverage, separate straw mulching, vetiver grass hedgerow+straw mulching treatment, the study aims to unfold itself revolving the specific water conversion effect of configuration technologies of two typical biological engineering measures and impact to some extent toward the soil nutrient, plant nutrients, agronomic traits of hypogaea especially and hypogaea yield, for the reasonable illustration of the difference in water conservation effect of two kinds of biotechnology alone and in combination, also the adaptability on gentle slope dryland with red soil, the results of which are as follows:1. Take Jiangxi Jinxian for example, study effects of straw mulching and vetiver hedge on runoff, soil erosion and hypogaea growth on red soil sloping land. Grass hedgerow plus straw coverage implies a great reduction in runoff volume which can statistically reduce runoff by47.10%～79.81%; As to the best treatment for holding ability of soil is also the adoption of grass hedgerow and straw coverage, directly the sediment can be reduced by79.17%～99.50%. Vetiver hedge plus straw mulching generated runoff and sediment nutrients carried in the least. Compared with the control, it can reduce the soluble nutrients carried in runoff (N, P, K) of37.92%～92.28%, reducing sediment organic matter carried up79.24%～99.49%, the total sediment carried in N, P, K content of43.58%～99.47%.2.2011-2012years of different treatments in seedling stage of hypogaea, blossom period, fruiting period, harvest period, soil organic matter, total nitrogen, total phosphorus, total potassium content were not significantly different, and there is no obvious distribution law; soil available nitrogen, available phosphorus, available potassium content generally have significant differences (p<0.05).Compared to the soil before sowing in2011, the processing of soil in2012during the hypogaea harvest gains a overall rise in soil organic matter, total nitrogen, total phosphorus, and even total potassium content, the increment of which reaches about0.81%～19.16%; In the meantime, there involves a significant drop in Soil alkali-hydrolysable nitrogen, available phosphorus, available potassium content of about4.31%～85.56%. On the whole, separate coverage or the processing alternative of grass hedgerow plus cover can lead to a steady mounting of soil organic matter, total nitrogen, total phosphorus, and total potassium content; the alkaline hydrolysis nitrogen, available phosphorus and available potassium take a relatively larger percentage than that after other treatment.3. The effect law of vetiver grass hedgerow and straw coverage upon the plant nutrients within hypogaea growth period hypogaeas growing in dryland red soil on the gentle slope is as follows:1) Single grass hedge processing of hypogaea plants indicates utmost uptake of soil rapidly-available potassium uptake, and comparatively larger changes in total potassium content in root, stalk or leaf of plant, which is significant enough.2) CK treatment implies relatively larger variations in available nutrient content of soil in whichever period of duration, and the exact content falls fastest, which may be caused by the continuous cropping of hypogaea which lead to degradation in soil degradation and subsequently the imbalance of newly input nutrient distribution.3) Separate straw mulching treatment was able to increase the total nitrogen, total phosphorus, and total potassium within soil, in which the covered straw can be returned to the embracement of available nutrients in soil after rotten degradation and ensure the distribution balance of the newly input available nutrient with no significant distinction.4) When it is covered in grass hedgerow with straw blanket, it can naturally increase the components within soil like total nitrogen, total phosphorus, total potassium, available phosphorus, available potassium, alkali solution nitrogen, as well as more varied quick-acting nutrient in different development stages of the hypogaea, manifesting in general a significant difference (p<0.05), change of total potassium content of plants being bigger and with significant differences. Due to the regularity of spatial distribution of soil and plant nutrient, in which it is seen that there is a lower percentage in Line1and higher in Line3and fitting the hypogaea yield and row number results, it is calculated that the optimal planting distance between vetiver grass hedge row is equal or greater than57cm.4. Separate straw mulching, or grass hedgerow with the addition of cover treatment can effectively increase the various fruits weight and kernel weight, namely effectively increase hypogaea yield. According to the reliable evidence in the size of the hypogaea annual production in2011and2012, it is found to follow the order of separate film mulch> grass hedgerow+straw cover> control> grass hedge alone, Among which, the first and second means of treatment produce significant increase in crop yield compared with that of the control treatment (31.74%～59.93%and15.23%～41.65%).Comprehensive the above analysis, it is recommended that the gentle slope dryland red soil region using vetiver hedgerow+straw mulching as soil and water conservation biological measures.