| Nitrogen and phosphorus in the soil as a necessary nutrient for plant growth and development, affecting the growth of vegetation and soil productivity, it is a key indicator of soil fertility. Zhoukou in Flooded Area of the Yellow River as the study area, through field investigation, indoor sample analysis, semi-variogram, GIS statistics module, ordinary correlation analysis, regression analysis, principal component analysis and other methods, analyse spatial variability characteristics of soil nitrogen and phosphorus and its influencing factors. research results are as follows:?1? the content of soil total nitrogen in the study area maintain middle(< 1500 mg·kg-1) level as a whole; ammonium nitrogen content is low(< 25 mg·kg-1) level as a whole; nitrate nitrogen content is higher(20-50 mg·kg-1) as a whole; total phosphorus content maintain high(600-1000 mg·kg-1) level as a whole; available phosphorus content in the medium and low(5-20 mg·kg-1) level as a whole. The nitrogen and phosphorus content in 20-40 cm soil layer is less than that of 0-20 cm, and the 0-20 cm layer change range is higher than that of 20-40 cm.0-20 cm and 20-40 cm in soil, soil total nitrogen content varied between 4.19-2078.10 mg·kg-1 and 0.78-1436.40 mg·kg-1, the average contents of 899.70mg·kg-1 and 578.10 mg·kg-1; soil ammonium nitrogen changes between 2.38-67.02 mg·kg-1 and 1.40-29.24 mg·kg-1, the average contents were 9.11 mg·kg-1 and 5.75 mg·kg-1; soil nitrate content changes between 0.04-1260.34 mg·kg-1 and 0.05-217.24 mg·kg-1, the average content was 71.17 mg·kg-1 and 35.68 mg·kg-1; the content of total phosphorus in soil varied between 307.45-2421.25 mg·kg-1 and 180.92-1906.61 mg·kg-1, the average content was 848.57 mg·kg-1 and 612.68 mg·kg-1; soil available phosphorus content varied between 1.32-103.21 mg·kg-1 and 0.41-74.81 mg·kg-1, the average content was 23.76 mg·kg-1 and 6.86 mg·kg-1.?2? the soil total nitrogen, ammonium nitrogen, total phosphorus, available phosphorus coefficient of variation between the 32.44-98.54%, it presented moderate?10-100%? spatial variability, soil nitrate nitrogen variation coefficient were greater than 100%, it showed a strong spatial variability. And the soil total nitrogen, ammonium nitrogen and nitrate nitrogen in 20-40 cm variation is less than that of 0-20 cm, while the soil total phosphorus and available phosphorus in 0-20 cm variation is less than that of 20-40 cm.Soil total nitrogen, ammonium nitrogen nugget coefficient between 36.51-49.98%?25-75%?, it maintain moderate degree of spatial correlation, spatial correlation of 0-20 cm below 20-40 cm, combination by human factors and natural factors. Soil nitrate nitrogen nugget coefficient showed strong?< 25%? spatial correlation and spatial correlation of 20-40 cm below the 0-20 cm, affected by natural factors. Soil total phosphorus nugget coefficient kept 6.55% in 0-20 cm, with strong spatial correlation, mainly affected by natural factors but 20-40 cm held 39.72% has moderate spatial correlation, affected combination by human factors and natural factors. Soil available phosphorus, two layers of nugget coefficient was 100%, spatial correlation is weak?75-100%?, mainly impacted on human factors, it has the trend of homogenization.?3? By correlation analysis and regression analysis, can be concluded that the soil nitrogen and phosphorus associated with soil organic carbon, pH, mechanical composition, climate have positive and negative correlation. The soil organic carbon and total nitrogen, total phosphorus, ammonium nitrogen, available phosphorus had a significant positive correlation, and has a negative correlation with nitrate nitrogen; soil pH?alkaline soil? has a negative correlation with soil total nitrogen, ammonium nitrogen, nitrate nitrogen, available phosphorus, there is a positive correlation the relationship with the total phosphorus; soil total nitrogen, ammonium nitrogen and total phosphorus will increase with decreasing the content of particles, which are correlated with soil clay content, soil nitrate nitrogen, available phosphorus increased with the content of particles, which are correlated with soil sand content has a positive correlation; between the annual average temperature and soil total nitrogen, ammonium nitrogen, nitrate nitrogen and available phosphorus, it has negative correlation with soil total phosphorus; there is a positive correlation between the annual precipitation and soil nitrate nitrogen, available phosphorus and soil total nitrogen, ammonium nitrogen, total phosphorus have negative correlation, the lower level of correlation will be lower than the upper.?4? the principal component analysis showed that the main influence factors can be divided into three types:artificial source?human factors?, natural source?natural factors?, artificial and natural comprehensive source?combination by human factors and natural factors?. In the 0-20 cm soil layer, three kinds of influence sources can explain 65.29% of the spatial variation, the artificial source?30.51%? > the natural source?18.28%? > the comprehensive source?16.50%?, and the main factor is the human factor. Close relationship between total nitrogen, ammonium nitrogen and human factors, nitrate nitrogen and natural factors are closely related, total phosphorus, available phosphorus and comprehensive natural factors have closely related; 20-40 cm soil layer, the three sources of influence can explain 67.35% of spatial variability, anthropogenic sources?30.05%? > natural source?19.47%? > comprehensive source?17.83%?, the same to human factors as mainly factors. The relationship between total nitrogen, ammonium nitrogen and human factors was close, nitrate nitrogen, total phosphorus, available phosphorus and comprehensive natural factors have closely relation.Based on experimental data and analysis, learning and understanding of the spatial variability of soil nitrogen and phosphorus in Flooded Area of the Yellow River meanwhile its relationship with influencing factors. It also provides theoretical and practical guidance for the further research as well as the soil database in Yellow River flood area.In theory not only can provide methods and technical support for other spatial variability of soil nutrients, also can provide data and theoretical support for the future agricultural development; In reality can not only ensure the safety of food production and natural resources, but maintain the sustainable development of regional agriculture and ecological environment. |
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