Evaluation Of Over Fertilization And Its Influencing Factors About Major Grain Crops In China

Over Fertilization not only increases the cost of grain production,but also poses a great threat to food security,soil security and water ecological environment security,which directly affects the sustainable development of social economy and human health.It has become the focus and hot spot of government departments and academia is how to effectively reduce the degree of excessive fertilization.It is of great practical significance to give a correct answer to the question,including where is the boundary of chemical weight loss and what are the crops and areas of focus for chemical weight loss,which is directly related to the success of the task of reducing chemical weight in China.From the perspective of economics,this paper employed Cobb-Douglas production function to evaluate the degree of over fertilization in the production of three major grain crops,rice,wheat and maize.Secondly,this paper employed spatial autocorrelation theory and hot spot analysis to analyze the spatial correlation pattern of over fertilization,which main production regions of rice,wheat and maize.Then,the spatial Durbin model was used to study the influencing factors of over fertilization.The conclusions showed that:(1)The average degree of over fertilization of the three major grain crops in China has reached 36.94%,which is relatively high.Rice production is overusing fertilizer by up to 43.48%,wheat production by up to 34.58%,and maize producers by up to 32.76%.(2)The temporal variation of over fertilization of the three grain crops has experienced two stages: the decline stage during 2002-2004 and the wavelike risen stage during 2005-2015.(3)From the perspective of spatial difference,the order of the degree of over fertilization of grain crops was as follows: South China > Middle Lower Yangtze Region > Huang Huai Hai Area > Northern Plateau Area > Southwest > Northwest > Northeast.(4)The degree of over fertilization about crops was distributed regularly,which the high value areas of rice‘s overuse fertilization mostly were concentrated in the Huang Huai Hai Area and South China,the high value areas of wheat’s overuse fertilization were distributed in Northern Plateau Area,Huang Huai Hai Area and Middle Lower Yangtze Region,and the high value areas of maize’s overuse fertilization were distributed in South China,Middle Lower Yangtze Region and Northeast.(5)The degree of over fertilization about rice,wheat and maize showed strong spatial autocorrelation,from its clustering characteristics view,wheat is the strongest,the rice is middle and the maize is the weakest.(6)The hot spot regions of rice’s over fertilization were mainly distributed in Huang Huai Hai Area,Middle Lower Yangtze Region and South China,and its cold spot regions were mainly distributed in Northern Plateau Area and Northeast;the spatial distribution of wheat’s cold and hot spot showed “hot in middle and cold in round”,which the hot spot regions were mainly distributed in Huang Huai Hai Area and Middle Lower Yangtze Region,and its cold spot regions were mainly distributed in Northwest;the pattern of cold and hot spot about maize was changed from “hot in south and cold in north” to “hot in east and cold in west”,which the hot spot regions were mainly distributed in Southwest,South China and Middle Lower Yangtze Region,and its cold spot regions were mainly distributed in Northwest.(7)The non-agricultural transfer of agricultural labor,the cultural level of agricultural labor and the disaster situation of crops have significant positive effects on the degree of excessive fertilization;the proportion of cash crop planting and agricultural technology services showed a significant negative depressive effect on the degree of excessive fertilization.(8)The per capita net income of rural households and the affected area have significant positive effects on the excessive fertilization in the region,and have significant negative effects on the excessive fertilization in the adjacent areas;agricultural mechanization level has a significant negative effect on the excessive fertilization degree in this region,and a significant positive effect on the excessive fertilization degree in adjacent areas.