| The phenomenon of side slope soil erosion in mining waste dump districts of steppe region is severe, making it hard for the process of vegetation restoration, which is heavily depended on artificial irrigations regarding the survival and growth of vegetation. Present study focuses on the traits of side slope soil erosion in mining waste dump districts, with the comparison between irrigation methods of micro sprinkler and drip irrigation been conducted. Due to the fact that soil erosion is easily caused by the surface runoffs of slope irrigation, proper irrigation methods and irrigation scheduling’ based on conditions of soil erosion and water-saving have become key factors in the processes of vegetation restoration. Thus, different controlling floor limits of irrigation amount (representing 55%,45%,35% of field moisture capacity) were deployed in this study, along with the suitability of micro sprinkler and drip irrigation in slope irrigation been assessed. Plus, obtained assessment results and ecological benefits were jointly analyzed, after which the appropriate irrigation scheduling of vegetation restoration in side slope areas was obtained, providing scientific references for the vegetation restoration in side slope regions of mining waste dump districts of steppe districts.Present study utilized soil moisture data of real-time changing and meteorological data of automatic weather stations, together with other field measurements combined, aiming to analyze the moisture migration patterns of slope irrigation under various irrigation methods. Also, the HYDRUS-1D model was used to simulate the moisture migration patterns of single measuring point, with the objective to figure out the water consumption law and optimal irrigation scheduling within the growth period of alfalfa. Results are as follow:(1) Regarding the HYDRUS-1D model in simulating the soil moisture of single side measuring points, results indicated that simulated values of soil moisture were close to those measured ones in the soil layer of 0-20cm, however, corresponding accuracy in soil layer of 20-40cm was lower than that of 0-20cm, illustrating relative poorer sensitiveness of deep soil layer than surface ones when exposed to short term precipitation or irrigation, since there might exist certain limitations in the HYDRUS-1D model when applied in simulating the soil water dynamic processes in areas dominated by vegetations.(2) Concerning the soil water dynamic in intermittent irrigation and different parts of side slopes, results showed that drip irrigation fitted better in controlling soil moisture in different slope positions. Generally, the distribution of soil moisture over the whole slope was comparatively more homogeneous, allowing more irrigated water infiltrated as well. Associated infiltration depth was more significant than that of micro sprinkler, meeting the requirements of soil water in the vegetation restoration process in slope areas.(3) Appropriate irrigation method and floor limits of irrigation amount in side slope regions were determined. With the comparison conducted between drip and micro sprinkler irrigation, the optimal irrigation method and floor limits of irrigation amount are:floor limit of irrigation amount of 45% was used for drip irrigation and associated irrigation quota was relatively lower, i.e.,125m3/mu, and the yield was 251.36kg/mu. Secondly, comparatively smaller yields were observed in various side slope areas, corresponding water consumption was 353.5mm, among which the maximum consumption was seen in budding and flowering period and its daily Water consumption rate was 4.0 mm/d, besides, the highest water use efficiency was detected as well, amounting to 10.67 kg/hm2·mm.(4) Relating the assessments of adaptability and ecological benefit, optimal irrigation scheduling of vegetation restoration in side slope areas was obtained. Detailed as, the irrigation amount of 45% served best in controlling the floor limit in drip irrigation which irrigated 8 times (3 times in June,3 times in July and 2 times in August), associated irrigation quota was 128 m3/mu. Also, the irrigation approach was intermittent irrigation which followed the order:upside slope-mid-slope-downside slope, with circulating irrigation conducted on these three slope positions, this procedure will continue till the whole irrigation is completed. |
PDF Full Text Request