Abstract:

【Objective】Improve the soil environment in the mining area and the ecological utilization value of coal based solid wastes and agricultural wastes.【Methods】Taking alfalfa as the test plant and no agricultural waste as the control group,pot experiment was conducted to analyse pure soil(N),5% weathered coal(A),5% coal slime(B),10% coal gangue(C)and the mixtures of 5% weathered coal+5% coal slime(AB),5% weathered coal+5% coal slime+10% coal gangue(ABC)combined with 5% agricultural waste cow dung(N+F,A+F,B+F,C+F,AB+F,ABC+F)on the growth and development of alfalfa and soil improvement.【Results】Applying coal based solid waste treatments C,AB,and ABC,the total biomass of alfalfa rose by 36%,45%,and 40%(P<0.05)in comparison to pure soil(N). Applying coal slime treatments B,AB,and ABC increased the key enzyme of nitrogen metabolism glutamic acid synthase(GOGAT)by 16%-19%(P<0.05). Applying weathered coal treatments A,AB,and ABC increased the key enzymes of alfalfa carbon metabolism acid sucrose invertase(AI)and sucrose synthase(SS)by 37%-52% and 19%-26%(P<0.05),respectively. Applying agricultural waste group(+F),the above ground biomass of alfalfa rose by 37% to 51%(P<0.05) in comparison to the control group and GAGOT,AI and SS activities respectively increased by 12% to 19%,19% to 37% and 19% to 26%(P<0.05). Compared with pure soil(N),soil organic matter of A,B,AB and ABC treatment increased 2.2-2.6 times(P<0.05).Compared with the control group,the content of soil dissolved organic carbon and available phosphorus in the agricultural waste addition group increased by 9%-15%,56%-194%(P<0.05);B+F,C+F,AB+F,ABC+F treatment group the activity of soil microbial carbon and nitrogen metabolism related enzymes S-β-GC and S-UE increased by 21%-183% and 13%-146% respectively(P<0.05). The combination of coal based solid waste and agricultural waste ABC+F was the best treatment for the principal component,with alfalfa biomass been the highest at 0.15 g/cm²;the activities of alfalfa key enzymes of carbon and nitrogen metabolism SS and GOGAT been the highest at 25.89 mg/(g·h)and 4.41 μmol/(g·min);soil organic matter comtent at the highest of 6.81%;enzymes related to soil microbial carbon and nitrogen metabolism S-β-GC and S-UE been the highest at 43.18 μg/(g·h)and 2.66 μmol/(g·min).【Conclusion】The ABC+F treatment significantly increased the biomass of alfalfa as well as the activities of key enzymes involved in the metabolism of carbon and nitrogen(AI,SS,and GOGAT),improved yield and quality of alfalfa,and was advantageous for promoting soil nutrient accumulation with the best effect on soil improvement.

Key words: Coal based solid waste, Agricultural waste, Alfalfa, Soil improvement, Mining area