Analysis Of Emission And Effect Factors Of Greenhouse Gases In Seeding Stsge From Winter Wheat Fields

In this experiment,we set up different sowing date and sowing rate experiments in three different ecological regions of Henan Province,including northern Henan,central Henan and southern Henan,to studing the impact of sowing date and sowing rate on greenhouse gas emissions from winter wheat farmland,and set 5 kinds of sowing dates and sowing rates respectively:CK(local traditional sowing time and sowing rate),B1(the sowing date is delayed by one week compared with CK,and the sowing rate is unchanged),B2(the sowing date is delayed by one week compared with CK,and the sowing rate is increased by 52.5 kg/hm~2compared with CK),B3(the sowing date is delayed by two weeks compared with CK,and the sowing rate is unchanged),B4(the sowing date is delayed by two weeks compared with CK,and the sowing rate is increased by 105 kg/hm~2compared with CK).Carry out pot experiments to explore the effects of temperature,moisture and fertilization methods on greenhouse gas emissions during winter wheat seedlings.The three-factor complete block design has two levels of temperature:T1(normal temperature)and T2(increased by 2-3°C compared to normal temperature);There are two levels of water treatment:W1(conventional irrigation)and W2(reduced irrigation).Fertilizer management has 5 levels:N1(100%compound fertilizer+0%organic fertilizer),N2(75%compound fertilizer+25%organic fertilizer),N3(50%compound fertilizer+50%organic fertilizer),N4(25%compound fertilizer+75%organic fertilizer),N5(0%compound fertilizer+100%organic fertilizer).The conclusions are as follows:1.In the experiment of delayed sowing date,compared with CK,the total amount of CH₄absorbed by each treatment in the three ecological regions showed an increasing trend,and the cumulative emission of N₂O showed a downward trend.The cumulative CO₂emissions of B3 treatment in the south have been reduced.Compared with CK,the comprehensive warming potentials of B1 and B3 treatments were reduced by 6%and 14%in northern Henan,7%and 27%in central Henan,1.3%and 15%in southern Henan.It can be seen that postponing the sowing date can reduce the comprehensive warming potential of the seedling stage farmland in the three ecological regions to varying degrees.2.In the experiment of increasing sowing rate,compared with treatments B1 and B3,the comprehensive warming potential of treatments B2 and B4 in northern Henan increased by 81kg CO₂-eq·hm^-2and 60.23 kg CO₂-eq·hm^-2,respectively;B2 and B4 in central Henan area decreased by196.6 kg CO₂-eq·hm^-2and 83.5 kg CO₂-eq·hm^-2,respectively;B2 treatment in southern Henan area increased by 19.1 kg CO₂-eq·hm^-2,while B4 treatment decreased 65.1 kg CO₂-eq·hm^-2.3.In the experiment of the interactive effect of sowing date and sowing quantity,compared with CK,the comprehensive warming potential of B2 and B4 treatments in northern Henan decreased by 1.5%and10.3%,respectively,and the B2 and B4 treatments in central Henan decreased by 15.1%and 30.7%,respectively.;the comprehensive warming potential of the B4 treatment in southern Henan is 18.3%lower than that of the CK treatment,which also has the effect of reducing carbon sinks,while the B2 treatment increased by 2.3%.4.Under the same water and temperature treatment conditions,the total CO₂emissions of each fertilization treatment differed significantly.The CO₂emission flux of the N5 treatment of pure organic fertilizer was the highest,the N1 treatment of pure nitrogen fertilizer was the lowest,and the N2 of other combined fertilization treatments,both N3 and N4 emission fluxes are higher than N1 treatment,and the higher the proportion of organic fertilizer,the higher the CO₂emission flux;the CH₄emission flux is absorption,and the average CH₄emission flux of all treatments is ranked from large to small,it is:N5>N4>N1>N3>N2;There is a significant difference in the total N₂O emission.The N₂O emission flux of N5 treatment with pure organic fertilizer is the highest,followed by N1 treatment with pure nitrogen fertilizer,and N2 with other combined fertilization treatments.Both N3 and N4 emission fluxes are lower than N1 treatment.5.Under the same temperature and fertilization conditions,the average emission flux of CO₂,CH₄,and N₂O of W1 treatment is higher than that of W2 treatment.The average comprehensive warming potential of W1 treatment is 15%higher than that of W2 treatment.In the same water and fertilization conditions,the average emission flux of CO₂,CH₄,and N₂O in T2 treatment is higher than that in T1treatment,and the average comprehensive warming potential of T2 treatment is 44%higher than that of T1treatment.