| Soil forms the backbone of the crops growth.A comprehensive and objective understanding of the actual fertility quality of the soil can not only promote the rational application of fertilizers and effective management of soil nutrients,but also achieve the sustainable development of agricultural resources.In this paper,soil samples which from Xiaomeng town,Da’an town,Caohe town,and Xinyan town of Yanzhou district of Jining city were taken as the research object.After field investigation,the soil fertility indexes of p H,organic matter,available phosphorus,alkali hydrolysable nitrogen and available potassium were established.The soil fertility of the experimentation area was evaluated synthetically and the spatial variability of soil nutrients was studied.The main research works in this paper include the following aspects.1.Present situation evaluation of soil fertility in Yanzhou district.Principal component analysis was applied to evaluate present soil fertility in Yanzhou district.According to the total frequency curve method,the soil fertility grades of Yanzhou were classified as: high fertility,middle fertility and low fertility.And the results showed that the soil fertility level of Yanzhou district was below the middle level.2.Dynamic evaluation of soil fertility in Yanzhou district.Markov chain progressive matrix method was applied to dynamically evaluate soil fertility in Yanzhou district.By calculating the progress of each nutrient,it is known that the soil organic matter has a rising trend because of a series of work to improve soil organic matter has launched in Yanzhou district.Because of the reduction in the amount of soil nitrogen fertilizer and the low utilization rate of nitrogen fertilizer in the Yanzhou district,resulting a large decline in the alkali hydrolysable nitrogen in Yanzhou district.Due to the unbalanced fertilization structure in Yanzhou district,there is a problem of “light phosphorus and potassium fertilizers” in the application of chemical fertilizers,resulting in a slight decline in available phosphorus and available potassium.Farmers should deeply apply nitrogen fertilizer and increase the application of phosphate fertilizers and potassium fertilizers in a period of vigorous crop growth.3.Descriptive statistical analysis of soil nutrients in Yanzhou district.The descriptive statistical analysis of the collected nutrients in Yanzhou district showed that the soil p H in Yanzhou district was weakly variable,and the available phosphorus,organic matter,available potassium,and alkali hydrolysable nitrogen were all medium-variable.The range of p H span in Yanzhou district was relatively small,the range of organic matter changes was not large.The range of available phosphorus,available potassium,and alkali hydrolysable nitrogen was relatively large.The distribution of these three nutrients in Yanzhou district was uneven.4.Study on spatial variability of soil nutrients in Yanzhou district.The spatial variability of soil nutrients in Yanzhou district was studied by the method of geostatistics and GIS.It was found that there was spatial autocorrelation in the soil nutrients except p H,in which the organic matter,available potassium and alkali hydrolysable nitrogen had strong spatial autocorrelation,and the effective phosphorus was in moderate spatial autocorrelation.From the largest to the smallest,the shift range was available phosphorus,organic matter,available potassium,and alkali hydrolysable nitrogen.According to the classification statistics,the contents of soil organic matter and alkali hydrolysable nitrogen in Yanzhou district were below the middle level,and the content of available phosphorus was abundant,and the content of available potassium was in the middle level.Through studying the spatial distribution pattern of each nutrient,it can be known that the soil organic matter content in Yanzhou district decreases from west to east,with the highest content of organic matter in the northwest,less content in the southeast,and least in the east.The content of alkali hydrolysable nitrogen was the highest in the central area,and was less in the northeast and west,and the least in the southeast.The contents of available phosphorus in the northeast and northwest regions were the highest,but the contents in the southeast and southwest regions were less,and the contents in the middle were the least.The content of available potassium was relatively high in the central and southern regions,while the content wass low in the northeast and northwest regions in Yanzhou district.5.Development of soil information system of Yanzhou district.In order to facilitate the collection,management and statistical analysis of soil nutrient data in Yanzhou district,the soil information system of Yanzhou district was developed.The functions of user login,user registration,soil fertility comprehensive evaluation and spatial variability analysis,soil information query,expert consultation,system management can be realized in this system,so as to realize the information management of soil fertility in Yanzhou district. |
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