Font Size: a A A

Study On Soil Water Holding Capacity And Nutrient Improvement Of Dumping Site In Open Pit Coal Mine Of Hei Daigou

Posted on:2022-04-24Degree:MasterType:Thesis
Country:ChinaCandidate:H Y GongFull Text:PDF
GTID:2480306479480954Subject:Ecology
Abstract/Summary:PDF Full Text Request
Open-pit coal mining can cause serious damage to soil ecosystem,and it is difficult to recover.After the exploitation of Hei Daigou open-pit coal mine,a large number of dumping sites were formed,and the soil structure was artificially changed.The natural harsh climate and vegetation conditions in the area increased the difficulty of the ecological system restoration.Based on the characteristics of the natural conditions,the international research frontier and the restriction of the actual treatment conditions,this study aimed at the two basic problems of"water shortage"and"fertilizer shortage"existing in the subsequent planting soil layer of the dump,we decided to use"water retaining agent"and"organic fertilizer"to solve the basic problems.On this basis,"microbial agents"were added to study the joint effects of the three soil improvement materials on soil ecosystem and plant growth and development.Firstly,the absorbent capacity,anti-evaporation capacity and water-holding capacity of water-retaining agent under different conditions were studied to determine the most suitable one.Then,the selected water-retaining agent,organic fertilizer and microbial agent were mixed into the soil according to different usage amounts,and the pakchoi was planted as the verification plant.The excellent material combination was judged by the change of soil physical and chemical properties and the change of the development of pakchoi.Finally,soil enzyme activity and microbial community of the selected excellent combinations were studied to judge the deep changes brought by the three improved materials.The main results of this study are as follows:(1)SNF water absorption ratio(311.65g/g),water absorption rate(80%of saturated water can be absorbed within 25min),anti-ionic capacity(0.1%NaCl-48.04g/g;0.1%Cacl2-21.39g/g;0.1%Fe Cl3-11.41g/g)and repeated water absorption capacity(the water absorption ratio of the seventh time can still reach 57.11% of the first time)are better than Han Dibao.The Polyglutamate type?powder cannot be tested because of dissolving in water.(2)After using three kinds of water-retaining agent in soil,it is found that the anti-evaporation effect of water-retaining agent in gel state is better than that in dry state.Based on the characteristics and application effect of water retaining agent,it can be seen that SNF water retaining agent has the best effect among the three kinds of water retaining agent,and compared with the amount of 1‰and 3‰,the amount of 5‰has the best effect on improving soil water retaining ability.(3)The use of water retaining agent and organic fertilizer can effectively reduce soil p H(original soil 8.3?8.93;improved soil 7.42?8.27);the soil electrical conductivity is increased(original soil 87?97?s/cm-1;improved soil 133?1046?s/cm-1);the content of soil organic matter is increased(1.82?2.23 g/kg in original soil;improved soil 13.8-63.8 g/kg);the content of alkali-hydrolyzable nitrogen in soil is increased(32.67?74.76mg/kg in original soil;improved soil 64.17?485.89mg/kg);the content of available P is increased(4.7?7.0mg/kg in original soil;improved soil 27.4?75.6mg/kg)and the content of available potassium(original soil 106.27?163.91mg/kg;improved soil230.20?427.94mg/kg).However,the use of microbial agents has no significant effect on soil physical and chemical properties.In summary,30%organic fertilizer usage is better than 10%and 20%improvement group in improving soil fertility.In addition,3‰or 5‰dosage of SNF water retaining agent can promote the effect of organic fertilizer.(4)The germination rate of pakchoi was not affected by soil improvement materials,and the application of microbial agents did not significantly promote the growth and development of pakchoi during the 50-day planting period.The growth performance of pakchoi is better with 5‰SNF water retaining and 30%organic fertilizer.The number of pakchoi leaves planted in the improved soil reached 8.7-9.7during the whole planting period,which is more than one time than that in the original soil(4.2).The plant height reached 14.4?15.7cm,which is more than twice that of the original soil(5.39cm).The total dry weight of the soil reaches 0.9?1.1 g,which is more than 7 times that of the original soil(0.12g).(5)The activity of alkaline proteinase was not affected by soil improvement materials and only increased with planting time.5‰SNF water retention agent and30%organic fertilizer can significantly increase the soil sucrase activity,soil urease activity,soil alkaline phosphatase activity,soil catalase activity and soil cellulase activity;microbial agents of 5mL or 10mL does not affect the activities of the six enzymes in the soil.(6)The soil samples had higher soil microbial community richness and diversity index at the later stage of planting.The application of 5‰SNF retaining agent and 30%organic fertilizer can significantly improve the soil microbial environment,while the use of 5mL or 10mL bacterial agents does not bring the similar obvious effects.The dominant bacteria in the experimental soil are Actinobacteriota and Proteobacteria,and the content in the original soil is higher.The main phyla that can improve soil properties and increase soil enzyme activity with increasing abundance are Bacteroidota,Firmicutes,Chloroflexi,Myxococcota and Gemmatiomonadota.Instead,Proteobacteria,Cyanobacteria,Bdellovibrionota,Armatimonadota,and Nitrospirota all have the opposite effect.In conclusion,the use of 5‰SNF water retention agent and 30%organic fertilizer can effectively improve soil water retention and fertility.If conditions permit,it is recommended to apply water retention agents in the gel form into the soil into the soil.
Keywords/Search Tags:Hei Daigou, dump, water-retaining agent, organic fertilizer, microbial agent
PDF Full Text Request
Related items