Effects Of Biochar On Soil Properties Of Maize And Greenhouse Gas Emissions

In recent years,global climate change has become the focus of global attention.Farmland soil emission is an important source of greenhouse gas emissions.The application of biochar in the improvement of farmland soil property and greenhouse gas emission reduction has become the focus of research at home and abroad.In this paper,the use of biochar which was prepared by straw resources was applied to soil.By setting different use level of biochar,including the no fertilizer treatment C0(0kg/hm2),the conventional fertilizer treatment CK(0kg/hm2)and biochar treatment C1(3000kg/hm2),C2(3000kg/hm2),C3(5000kg/hm2),C4(7000kg/hm2),the effects of soil property,soil CO2 and N2O emission fluxes and cumulative emissions on agronomic traits and yield of maize were studied.This will be of great significance for agricultural carbon sequestration and food production in northeast China.The experiment was conducted at the experimental base of Shenyang Agricultural Uinversity in 2016,Experimental results show:(1)The effects of biochar on soil fertility and nutrient content were significantly improved.Compared with the nutrient content in soil before sowing,biochar can effectively improve the content of organic matter,available nitrogen,available phosphorus and available potassium in harvested soil,in which only available nitrogen content has no significant difference with before sowing.The content of organic matter and available phosphorus increased with the increase of biochar.(2)The emission flux of CO2 in soil with different biochar addition increased firstly and then decreased.There was a significant positive correlation between soil temperature at 5cm and soil CO2 emission flux,except C1.In the whole growth period of corn,the soil CO2 cumulative emissions of different treatment was as follows:Jointing-Flowering stage>Flowering-Milky stage>Seeding-Jointing stage>Dough-Full ripe stage>Milky-Dough stage>sow-seeding stage.(3)The relationship between the cumulative emission of CO2 in different treatments was C4>CK>C3>C2>C1>CO.Compared with CK,C4 increased the cumulative emission of soil CO2 by 1.5%,while C2 and C3 decreased by 9.9%and 8.0%,respectively.The results indicated that the addition of a certain amount of biochar to soil could inhibit the intensity of soil respiration to some extent,so as to inhibit the emission of CO2 in the soil,but if the amount of biochar was too much,it would promote the emission.(4)During the whole growth period of Maize in 2016,the soil N2O emission flux was mainly affected by nitrogen application.The emission flux of N2O in the basal and top dressing increased significantly and had obvious emission peak.Adding biochar could affect the cumulative emission of N2O significantly,and with the increase of biochar,the cumulative emission of N2O decreased gradually.Compared with CK,the soil N2O cumulative emissions of C2,C3,C4 were reduced by 24.7%,35.2%,37.0%in maize growth period.The results indicated that the addition of biochar had a certain inhibitory effect on soil N2O emission,and with increase of biochar,the soil N2O emission decreased gradually.(5)From the agronomic traits of maize,the addition of biochar could promote the growth of maize,increase the stem diameter and leaf area significantly.It can also delay the wilting of plants,reduce the rate of decline of leaf area,and increase the time of plant growth.For the height of maize,the growth of maize plant height was inhibited in the early growth stage,but in the later growth period,the inhibition disappeared gradually.(6)For the yield of maize,the addition of biochar had no effect on the dry matter accumulation in seedling stage and jointing stage.However,with the advance of the growth period,it had a certain effect on the formation and accumulation of dry matter in Maize plants.Under the premise of equal nutrient with CK,biochar can make maize ear weight and hundred kernel weight increased significantly,while in the case of insufficient fertilization,biochar can make maize yield components had no significant difference compared with CK.In the case of reduced nutrient 30%,the addition of biochar could increase maize yield to the same level as CK;under the condition of sufficient fertilizer,the addition of biochar could increase the yield of maize significantly.Compared with CK,the economic yield and biological yield of C2,C3,C4 increased by 9.8%,8.7%;10.7%,9.3%;11.7%,13.7%,respectively.The economic yield of C1 was lower than that of CK,which was 0.5%.and the biological yield increased slightly compared with CK,which was 0.1%.There was no significant difference between economic yield and biological yield with CK.In summary,adding biochar to soil can increase soil nutrient content and restrain greenhouse gas emission.At the same time,it can promote the growth and development of maize,and it can also increase the production significantly.Compared with conventional fertilization,the addition of biochar to soil could increase the utilization ratio of fertilizer and fertilizer.Therefore,the results of this study show that biochar is of great significance for carbon sequestration in dry land farmland,improving the soil properties of Maize dry land and maintaining the stable yield and sustainable development of agriculture.