Study On Conservation Tillage Technology For Preventing Soil Erosion By Wind In Dry Farmland Area

Soil erosion by wind is an important factor causing aeolian sand drift, desertification and dustand sand storms in arid, semi-arid regions. It has aroused public attention as a problem ofendangering agriculture and the development of social and economy. Because soil grain on soilsurface can be redistributed by wind in time and spatial, agricultural activities and economy mustbe influenced, especially in dry farmland area. In winter and spring season, farmland is uncoveredwith vegetation, and soil is very dry. Additionally, extensive conventional cultivation results inserious soil erosion because of fragile eco-environment. Therefore, it is important to changetraditional tillage and establish new tillage technology in order to promote sustainable agriculturaldevelopment and improve the environment.On the basis of research on wind erosion and conservation tillage at home and abroadresearch report on conservation tillage's quantification can be provided for dry farmland areacomparing different tillage technology.Xiaohetao village in Taipusi County, Inner Mongolia,was selected as the study area. Duringthe period of crop growth, nine tillage modes were disposed in the field, including no-till, subsoiltillage, conventional tillage, plowing with stalk mulch, surface tillage, ridge tillage 15cm (1:12)ridge tillage 25cm (1:6), ridge tillage 15cm (1:6), and ridge tillage 25cm (1:24). In the period offallow farmland, thirteen tillage modes were disposed including plowing with stalk mulch,conventional tillage, subsoil tillage, surface tillage, ridge tillage, high stubble of wheat (height ofstubble is 45 cm), low stubble of wheat (height of stubble is 10 cm), high stubble of rape (heightof stubble is 45 cm), low stubble of rape (height of stubble is 10 cm), and low stubble of benne(height of stubble is 10 cm). Through field observation, wind tunnel test and data analysis, soilmoisture, crop growth, near surface wind velocity and soil erosion by wind were systematicallydiscussed in this paper. Some conclusions are drawn as follows.(1) Soil moistureDuring the growth period of rape, soil moisture from 0 to 70 cm depth of ridge tillage is thehighest in the nine tillage modes, that of no-till and surface tillage are the lowest, and that ofplowing with stalk mulch, subsoil tillage and conventional tillage was moderate.After harvesting of crop, comparing stalk returning farmland and plowing, subsoil tillage,conventional tillage, low stubble of wheat and high stubble of wheat, content of soil moisture ofhigh stubble of wheat is highest from 0 to 30 cm, those of subsoil tillage and conventional tillageare placed in the middle, and those of stalk returning farmland and plowing and low stubble ofwheat are lowest.(2) Crop growthOn the basis of field observation and data analysis, the height and coverage of rape ofplowing with stalk mulch is the largest of nine types tillage modes, those of no-till are the smallest.Furthermore, the weight of fresh matter and dry matter of individual plant and 1 square meterweight of dry matter of nine types tillage modes are all increasing with time, such are amplitude.Those of plowing with stalk mulch are the largest of all, and those of no-till are smallest.Moreover, yield of plowing with stalk mulch is also the highest, and that of no-tillage is thelowest.(3) Near surface wind velocityRoughness and friction velocity are increasing with the growth of rape in nine tillage modes.The mean roughness and friction velocity of plowing with stalk mulch is the largest, and those ofno-till are smallest.In fallow period, roughness and frictional velocity of ridge tillage 25cm (1:6) and highstubble of wheat (height of stubble is 45cm) are largest of thirteen tillage modes, its abilitypreventing soil erosion is the best;those of conventional tillage are the smallest, and its abilitypreventing soil erosion is the poorest.(4) Soil erosion by wind on farmlandAccording to the result of wind tunnel test, some conclusions are drawn for subsoil tillage,plowing, plowing and scrunching, stubble of wheat (height of stubble is 10cm), stubble ofbuckwheat (height of stubble is 10cm), stubble of benne (height of stubble is 10cm) andno-stubble. The difference of tillage modes resulted in different deflated matter in the 0-20 cmheight. The wind-eroded matter of plowing and scrunch is the largest, and that of the stubble ofbenne is the smallest. The order of wind-eroded matter for seven tillage modes is as follows:plowing and scrunching>no-stubble > stubble of buckwheat > subsoil tillage > plowing > stubbleof wheat > stubble benne. Furthermore, the difference of tillage modes also resulted in differentrelationships between rate of soil deflation (Rd) and wind velocity. Rd of plowing and scrunching isthe largest, and that of stubble of benne is the smallest. The order of Rd for seven tillage modes isas follows: plowing and scrunching > no-stubble > subsoil tillage > stubble of buckwheat >plowing > stubble of wheat > stubble benne. The result of wind tunnel test indicated that theeffects of preventing soil erosion by plowing and scrunching and no-stubble are the poorest, andthose of stubble of benne, stubble of wheat and plowing are the best, and those of subsoil tillageand stubble of buckwheat are placed in the middle.According to the research results, during the course of growth of crop, there are higher soilmoisture content, larger roughness of soil surface and better growth of crop for plowing with stalkmulch and conventional tillage. Furthermore, there is low cost for group one. Plowing with stalkmulch is better than conventional tillage in the growth of crop and preventing wind erosion. Afterharvest time, conventional tillage is the poorest of all the tillage modes for preventing winderosion. For group two, there is high soil moisture content, but the growth of crop and wind statusnear ground is placed in the middle. Ridge tillage not only needs a great deal of surface soil, butalso has high cost. Additionally, for group three, the cost is very low, but soil moisture contents arethe lowest for surface tillage, no-till and subsoil tillage. In period of fallow, high stubble is the bestfor promoting the content of soil moisture and preventing soil erosion by wind.In conclusion, in order to improve soil moisture content, prevent wind erosion and increaseyield of crop, plowing with stalk mulch should be selected in the growth period, and high stubbleshould be selected after the harvest time.In this paper some innovation are listed as follows: soil moisture, crop, near surface windvelocity and soil erosion by wind on farmland were systematically observed and summarized.Accordingly, a useful and feasible technology is put forward for conservation tillage in dryfarmland regions. This technology is benefit not only for increasing yield of crop, but also forpreventing wind erosion.