Spatial-temporal Variation Of Soil Fertility Of Cultivated Land And Analysis Of Influencing Factors

Cultivated land is an indispensable material basis and carrier for agricultural production.The quality of cultivated land directly affects national food security and is also closely related to sustainable development of environment and ecology.The contradiction between the rapid population increase and the sudden decrease of cultivated land now makes the protection of cultivated land quality urgently need attention.The influencing factors of changes in cultivated land quality are the result of the natural evolution process and human activities.The interaction of people on cultivated land has increased in recent years,mainly due to the reduction of the sown area of food and crops,the unbalanced application of chemical fertilizers and the benefits of fertility Inferior problems.Previous studies on soil fertility changes have focused on structural studies with relatively few studies on socio-economic factors.In terms of time,the study is mainly compared 2000 with the second national land survey to study the changes of cultivated soil fertility and its impacts after 2000.The aim is to provide a more comprehensive understanding for farmers and corresponding managers in the region and to provide theoretical and practical guidance for the development of precision agriculture,ecological agriculture and organic agriculture.This dissertation takes Hefeng County in Hubei Province as the research area,supported by the project in Investigation and Evaluation of Cultivated Land Quality Grade in Hefeng County and based on the data of soil measurement formula in 2010 and 2017.The two-phase data evaluation indicators are selected as organic matter available phosphorus,available potassium and pH,combining traditional statistics,geostatistics and GIS technology;Changes of the content level,spatial structure variation and spatial-temporal pattern distribution of organic matter,available phosphorus,available potassium and pH in the county during the past eight years were studied.The spatial and temporal changes of soil comprehensive index were also analyzed.Field measured data and socio-economic data of Hefeng County were collected through field investigation and the influence of this data on soil fertility changes was analyzed.The results of the study show that the fertility of cultivated land in Hefeng County has increased in the past eight years.Except that the content of available potassium in the soil has decreased over the past eight years,the content of organic matter,available phosphorus and pH have increased to varying degrees.Overall,the content of available potassium and pH are lower,while the content of organic matter and available phosphorus are higher.In terms of spatial distribution,the distribution patterns in the two periods are roughly similar,with the northern part being high and middle part being low.The spatial structure variation is weakened,indicating that the influence of human factors has increased.In the analysis of influencing factors,soil fertility is affected by structural factors such as soil type,topographic conditions and soil texture,and random factors such as fertilizer application,agricultural planting structure and social and economic development.The intervention of human factors is becoming more and more important.The reason for the decreaseof available potassium contentin soil is the unbalanced structure of chemical fertilizer application,more nitrogen and phosphorus fertilizer and less potassium fertilizer.The amount of chemical fertilizer applied per mu is too high,which is likely to cause decline in soil quality.Based on its research results,the following countermeasures are proposed:Promote soil testing and formula fertilization,scientifically guide farmers to balance fertilization,reconcile soil acidification problems and reduce the amount of phosphate fertilizer application;improve the rural land system,actively guide land circulation,alleviate the phenomenon of idle farmland;increase agricultural subsidies,input long-term protective subsidy for cultivated land,actively guide farmers to apply more farm manure and green manure,return straw to the field,reduce chemical fertilizers and pesticides,promote awareness of cultivated land protection.