Effects And Assessment Of Different Remediation Measures On Soil Fertility Quality In Mining Area

The development and utilization of mineral resources promote the development of economy, but also have a significant impact on the environment, especially the soil pollution and waste of land resources,which affect the sustainable development of economy, society and ecological environment directly, and become one of the hot issues in the current social and economic development. Therefore how to use cultivated land resources, optimize the structure of arable land, fertilize soil and increase crop production and quality become a very important issue in the remediation of contaminated soil.In this paper, the Tongguan Mining Area of Shaanxi Province was chosen as the research object.Through the field investigation and sample analysis, study on the effects of different restoration measures on soil fertility to find the best restoration model of fertility restoration on contaminated soil. Through the analysis of the fertility index and evaluation of soil fertility quality to determine the measures to improve the fertility and fertilize rationally, which can provide scientific guidance for the abandoned agricultural production in gold mine areas. Conclusions are presented as follows:(1) The lack of nutritional elements and maldistribution in the soil of Tongguan gold mine is very serious. After engineering remediation the soil fertility was obviously improved under three engineering remediations except soil-mulching measure. Generally consider all respects, the better restoration measure is the 40 cm upper and lower turns measures. According to the classification of soil nutrient content and compared with the control soil the fertility indexes were improved, after the restoration the soil organic matter and alkaline nitrogen content improved from level 5 to level 4. Available phosphorus content improved from level 5 to level 3. Total nitrogen content improved from level 6 to level 5. Total phosphorus content was always under level 2.(2) Plant wheat and rye on the soil after engineering remediations, all soil fertility indexes were improved compared with the control soil. Compared with the soil only after engineering remediation measures, the content of organic matter, total nitrogen, and total phosphorus change slightly, alkali solution nitrogen content decreased slightly, available phosphorus content increased greatly. This shows that the soil fertility change slightly after the engineering remediations. The nutrient content of 0~20cm soil is higher than that of 20~40cm soil in addition to the soil after soil-mulching measure. Wheat’s ability to protect fertilizer was higher than that of rye. The best effect of remediations was 80 cm upper and lower turns and wheat.(3) The soil moisture content has strong seasonal changes, the soil moisture content shows a trend from high to low from December to June. With the increase of soil depth, the soil moisture content generally shows the change trend that increase firstly and then decrease. The effect of engineering treatment measures on soil water content is not very significant, which shows that the engineering treatment measures and crop structure adjustment have no significant effect on soil water content. The water holding capacity of wheat is higher than that of rye.(4) There are great differences in the traits of crops and economic output under different remediations, which reflects the difference of soil productivity. Compared with traits and yield of soil crop after repair, Overall presents that: 80 cm upper and lower turns>40cm upper and lower turns>20cm upper and lower turns> soil-mulching measure. Per mu yield of wheat was higher than that of rye. The highest yield was 80 cm upper and lower turns and wheat, its mu yield reached 518.4kg. This shows that in the mining area can achieve the purpose of production and repair.(5) From the results of soil fertility quality assessment, the level of soil comprehensive fertility was increased under engineering measures compared with the control soil. Fertility quality index increased from 0.24 to 0.65 after the repair, the quality of soil fertility increased by 1.7 times compared with that before. The soil fertility level was the highest in 40 cm upper and lower turns, which was 0.66. The soil comprehensive fertility index changed little after planting crops, 0~20cm in the wheat soil with an average of 0.70 and an average of 0.65 rye soil, 0~20cm soil comprehensive fertility index was higher than 20~40cm, wheat soil is higher than rye soil. The soil comprehensive fertility index of 80 cm upper and lower turns with wheat measures was the highest, which was increased from 0.24 to 0.84, which was 2 times higher than that of control soil.(6) Compared with the control soil, under the combined action of engineering remediation, tillage and fertilization, the soil fertility level was improved and good remediation efficient was acquired. Although the soil fertility quality has improved after the restoration but some of the fertility index is still not high. We need to take further improvement measures in the later period to ensure the realization of the benign development of mine soil.