| In order to improve soil fertility in the apple orchard of Loess Plateau,expand the source of organic manure,and provide theoretical basis for scientifically using white clover,composting of white clover was proceeded to realize efficient use of white clover.Firstly,white clover and chicken manure were used as nitrogen source,and the wheat straw was used as carbon source to adjust the C/N value to 30.Then the mixed fertilizer with mass ratios of 1:0,1:0.5,1:1,1:2,and 0:1?chicken manure to white clover?were used to determine the dynamic changes of physical and chemical indexes and nutrient in the process of composting of different quality ratios of white clover and chicken manure to find the best composting ratio.Secondly,composting of white clover and wheat straw or apple-tree leaves was proceeded to determine the best C/N value.Three C/N value treatments?T25,T30 and T35?were conducted to detect effects of different value on change rules in physics and chemical indexs and nutrient content.Meanwhile,the fertility effects of white clover composting with wheat straw and apple-tree leaves as carbon source were compared.The best rate of composting can provide theoretical basis for efficiently using white clove and alleviating the shortage problem of organic fertilizer.The main results are as follows:?1?The white clover can be used separately as a nitrogen source to compost and the process is faster than chicken manure.In the five ratios composting of chicken manure and white clover,the temperature of the composting,in which the white clover was used separately as a nitrogen source,reached high temperature period after only 4 days,which was shorter than the other treatments.And its pile temperature reached room temperature after about 40 days.In addition,the days that the temperature of the pile was higher than 55°C were more than 3 days,which met the requirements of harmlessness and maturity.?2?In the five ratios composting of chicken manure and white clover.The pH of composting under each treatment increased firstly and then decreased,and the final pH stabilized between 7.08 and 7.53.The conductivity of each treatment showed an upward trend,and the final conductivity ranged from 2.66 ms·cm-13.74 ms·cm-1.The correlation between chicken manure addition ratio and final conductivity was positive.The conductivity of the treatment in which the white clover as a nitrogen source alone was lower significantly than other treatments?P<0.05?.The organic carbon contents of the mixed fertilizer with mass ratios of 1:0,1:0.5,1:1,1:2,and 0:1?chicken manure to white clover?were respectively417.1 g·kg-1,415.4 g·kg-1,360.1 g·kg-1,401.9 g·kg-1and 380.2 g·kg-1.The contents of total nitrogen,total potassium,available potassium,and nitrate nitrogen of the treatments in which the proportion of white clover was more than half have no significant differences,but were significantly higher than the other treatments.as relatively faster than other treatments?P<0.05?,while the contents of total phosphorus were lower significantly.The greater the proportion of white clover,the lower the ammonium content of compost products.?3?During the composting of wheat straw and white clover with different C/N ratios,the days that the temperature of pile under 35 C/N ratio was higher than 50°C were for more than one week,which achieved the requirements of harmlessness and maturity.The temperature of the compost reached high temperature after 6 days and it reached around room temperature in28 days.The pH of composting under each treatment was increased firstly and then decreased,and the final pH was stabled between 7.13 and 7.55.The change of conductivity in all treatments showed an upward trend.The final conductivity ranged from 2.66 ms·cm-1 to 3.08ms·cm-1,and the final conductivity was the lowest at 35 C/N ratio.The total carbon contents of the three treatments with C/N of 25,30,and 35 after composting were reduced by 17.4%,22.1%,and 23.1%,and total nitrogen was increased by 12.2%,54.6%,and 91.7%,respectively.The total phosphorus increased by 63.1%,71.1%,and 101.1%,the total potassium increased by 63.9%,61.1%,and 102.6%,the nitrate nitrogen increased by 3.0,2.0,and 1.6 times,and the available phosphorus increased by 65.1%,88.8%,and 49.6%.The potassium increased by 82.7%,84.1%,and 107.4%.In addition,the ammonium nitrogen levels at 25 and 30 C/N treatments were 3.2 and 2.7 times higher than before composting,respectively,while C/N 35 treatment was 58.3%lower.?4?During the composting process of apple leaves and white clover with different C/N ratios,the days that the temperature was higher than 55°C under the 30 C/N ratio treatment were more than 3 days,which achieved the requirements for harmlessness and maturity.The temperature of the pile reached the high temperature after 4 days.The final pH of pile under each treatment was stabled between 7.56 and 8.82.The change of conductivity under each treatment showed an upward trend,and the final conductivity was between 1.48 ms·cm-12.64ms·cm-1.After composting,the organic carbon content of the treatment which the C/N was 35was significantly higher than the other treatments?P<0.05?;The relationship of the contents of total nitrogen,total phosphorus,total potassium,available phosphorus,and available potassium was C/N 30>C./N 25>C/N 35.And each treatment was significantly different?P<0.05?.The content of nitrate nitrogen at 30 C/N was significantly higher than the other treatments?P<0.05?,while the content of ammonium nitrogen was not significantly different in three treatments.?5?The content of total carbon,total nitrogen,total phosphorus,total potassium,and ammonium nitrogen in organic fertilizers when white clover composted with apple leaves was higher than that with wheat straws,while the content of nitrate nitrogen was lower.Different compost materials,the best initial C/N for composting was different.When apple leaves and white clover were used as compost materials,the optimum C/N is 30.When composting with wheat straw and white clover,nutrient content of different C/N treated compost products and the variation range of nutrient content before and after composting varied with different nutrient types.The C/N 25 had the highest content of organic carbon,ammonium nitrogen,and quick-acting phosphorus,the lowest total carbon reduction,and the largest increase in ammonium nitrogen and nitrate nitrogen.The C/N 35 had the highest contents of total nitrogen,total potassium and available potassium,and the contents of total nitrogen,total phosphorus,total potassium and available potassium increased the most.The C/N 30treatment had the highest total phosphorus content and the available phosphorus had the largest increase. |
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