Change Of Soil Organic Carbon And Coupling Relationship Between Carbon And Nitrogen In Facility Agriculture

Facilities for agricultural soil in special environmental conditions,in this paper,by comparing the Qinghai eastern facilities area under different planting of agricultural soil basic nutrients,organic matter,carbon and nitrogen relationship and its influence factors,such as typical fixed number of year of the analysis of different plant facilities in the soil nutrient content changes,organic matter and carbon and nitrogen relationship,the following results:With the increase of plantation age,the contents of total nitrogen,total phosphorus,alkali-hydrolyzated nitrogen and available phosphorus in the soil showed an overall increasing trend,reaching 1.55g/kg,4.57g/kg,196.98mg/kg and88.44mg/kg in 10-20 years,respectively,which were 47.62%,75.10%,47.21% and45.17% higher than those below 3a.Soil organic matter content in 3～5a,5～10a and10～20a increased by 31.91%,22.57% and 48.68% significantly compared with that below 3a.The content of soil total K showed an irregular curve change with the extension of plantation age,and there was no significant change overall.The content of available K decreased slowly from 3 to 5 years after planting years,and the content of available K dropped to the lowest level at 10 to 20 years,which was 153.73mg/kg.The pH value showed an overall downward trend with the extension of planting years.After 10-20 a,the pH value decreased significantly,which was 3.2% lower than that of3 A.The overall electrical conductivity showed a trend of gradual increase.The soil electrical conductivity reached 394μm/cm at 10～20 years.The extension of with increasing years of planting,soil organic matter change rule of bimodal trend,in 3 ～ 5 a peak for the first time,the organic matter content up to 20.31 g/kg,3 a significantly increased by 31.889%,then declined slightly,the second peak was achieved at 10 ～ 20 a,organic matter content up to 22.89 g/kg,and significantly higher and other fixed number of year of organic matter content,soil total organic matter as a whole showed a trend of increase.The proportion of heave fraction organic matter was 75.38% on average,and decreased slowly with the increase of planting years.The proportion of heave fraction organic matter was80.23% at ≤ 3 a and 72.19% at 10-20 a.The proportion of light fraction organic matter increased from 19.77% at ≤ 3a to 27.81% at 10-20 a,with an overall increase of40.67%.The soil C/N ratio of facility agriculture in this region ranged from 15.70 to16.74.With the increase of plantation age,the soil C/N ratio increased at first and then decreased.The C/N ratio reached the maximum at 5-10 years,and increased by 6.62%compared with ≤ 3a.The organic matter and total N contents in the facility soil showed a certain linear correlation under different plantation age,and the correlation coefficient was 0.81,indicating a good degree of fit.The relationship between total N and heave fraction organic matter and light fraction organic matter in soil was also linear,and the correlation coefficient was 0.6029,respectively.0.6104,has a strong correlation.Soil organic matter has a linear relationship with pH and conductivity.The content of organic matter decreases with the increase of soil pH,showing a negative relationship,and the occupation factor is 0.75.The correlation coefficient between organic matter and conductivity is 0.5404.According to Pearson correlation analysis,the soil physical and chemical indexes between at P = 0.01 and P = 0.05 level(double side)on all show some correlation,soil total N,total P,alkaline hydrolysis nitrogen,available phosphorus,organic matter,heave fraction organic matter and light fraction organic matter showed a significant correlation between plantation age,total N,alkaline hydrolysis nitrogen and organic matter to achieve significant correlation,total P,available phosphorus and alkali solution nitrogen significantly relationship between;There was a negative correlation between available K and total K and soil indexes,but no significant correlation was found between available K and total K.There was a significant negative relationship between pH and soil conductivity and organic matter.There was a significant correlation between soil conductivity and organic matter.There was a significant negative relationship between plantation age and soil pH value,a significant positive relationship between plantation age and soil electrical conductivity,and an extremely significant positive relationship between plantation age and organic matter.Select soil indicators of different planting years and facilities areas for principal component analysis of soil nutrients,and perform general statistical descriptions on the comprehensive scores of the 71 soil sample points that are finally calculated: the score range is 12.8-48.4,the average is 26.9,and the standard deviation is 8.1,the coefficient of variation is 33.1%,which is a medium degree of variation.From the perspective of administrative regions,the IFI value is ranked from high to low as:Huzhu County>Ping’an District>Ledu District>Minhe County,and the average values are: 32.0,29.9,28.8,and 19.8,respectively.The principal component analysis results show that the extracted principal components 1-4 can reflect 71.896% of the soil index information.