Effects Of Organic Material Returning And Reducing Nitrogen Fertilizer On Ecological Footprint And Ecological Service Value Of Winter Wheat

A series of agricultural problems resulting from laying one-sided emphasis on high yield has received considerable attention,such as the decline of farmland quality,low utilization efficiency of fertilizers,and severe environmental pollution.To implement organic material to soil,can not only overcome some adverse effects caused by single application of N fertilizer,but also address agricultural waste(such as straw,manure)pollution problems.In this research,three kinds of organic material were chosen to add in field combined with the reduction of N fertilizer.And the treatments were set as : adding N fertilizer only(CK),directly returning straw to farmland with 90% pure nitrogen of CK(J),returning manure on the basis of 85% pure nitrogen of CK(JF)and returning fungi residues slurry on the basis of 85% pure nitrogen of CK(JZ).The chemical and physical character of soil and the growing situation of wheat in different treatments were measured.The effects of replacing part of nitrogen fertilizer by organic material on the ecological footprint and ecological service value of wheat ecosystem has also been analyzed.The results were as follows:1.The water preservation capacity of the soil especially 80-100 cm soil moisture has been considerably strengthened by organic material returning.And the water use efficiency of wheat fields in manure returning treatment were also increased than those of CK.The three treatments significantly increased the Fv/Fm value of wheat leaves after jointing stage.J treatment significantly increased the soil inverses activity,JF treatment significantly increased the soil inverses activity at the late Stage of Wheat,The three treatments significantly stimulated the growth of winter wheat than CK,J treatment increases dry matter accumulation significantly,JF treatment has a better effect on increasing the grains per spike and grain number,The three treatments significantly increased grain yield.2.Returning different organic materials to field contributed to the accumulation of soil organic carbon.JF and J treatments had considerably increased soil organic carbon content.The increased effects of JZ treatment was mainly embodied in late wheat growth period.Three treatments significantly increased soil respiration rate along with the process of growth stage.Reducing nitrogen fertilizer could also reduce soil emissions of greenhouse gases,especially in JZ treatment,thus effectively reduces the role of farmlandeco-system in the process of global warming.3.Organic materials returning to field could improve the total nitrogen content of the soil at the early growth stages of wheat,and promoted the absorption and utilization of wheat on soil nitrate nitrogen,moreover soil available nitrogen content has also been elevated.JF and JZ treatment improved plant nitrogen accumulation in wheat,all treatments had improved the spatial factor productivity of nitrogen,and ultimately improved the nitrogen use efficiency of wheat,JF and J treatments had the best effect.4.Three treatments had significant effect on reducing the ecological footprint in the wheat field eco-system.Fertilization reducing reduced the grey water footprint in agricultural production,adding organic materials reduced the consumption of green water,thereby reducing overall water footprint.J treatment reduced the amount of soil carbon emission,other organic materials has increased the amount of carbon absorption,eventually reducing the carbon footprint.All three treatments reduced the effects of fertilizers on nitrogen footprint,thus reducing wheat field nitrogen footprint.Three organic materials returning significantly increased climate-controlled value,environment cleaning up value,water conservation value,soil organic accumulation value of wheat field system.J treatment significantly increased agricultural service value and climate regulation value of wheat field system.Z treatment significantly increased agricultural service value of wheat field system,which has played an active role in sustainable development of agro-ecosystem.In a word,returning organic material and reducing the amount of N fertilizer has promoted the growth and development of wheat as well as the photosynthetic characteristics,increased soil enzyme activity and improved soil nutrients which was shown by the increase of TOC and TC.The returning of organic matter reduced greenhouse gas emission and improved WUE and NUE of wheat without a decrease of crop production and the ecological service value of wheat field has been enhanced,while lowering ecological footprint,which could be an efficient way to improve agricultural environment and develop circular agriculture.