Research On The Effects Of Different Planting Patterns In Double-cropping Rice Fields On Greenhouse Gas Emissions And Soil Aggregates

The multi-cultivation planting model of great significance for improving land use efficiency,increasing grain output,and ensuring food security in the rice regions of Southern China.They research is based on Southern double-season rice,and planting potatoes,rape,radish,purple Yunying and ryegrass,formed:early rice-late rice-potato（rice rice potato）,early rice-late rice-rapeseed（rice rice oil）,early rice-late rice-radish（rice rice Bu）,early rice-late rice-Ziyunying（rice Rice fertilizer）,early rice-late rice-rye grass（rice straw）five different multi-cultivation planting models,and with early rice-late rice-idle（rice rice idle）as a control,analyze the different rice field planting models on greenhouse gas emissions,soil agglomeration The impact of organic carbon pools on soil and soil provides a theoretical basis for the sustainable development of multi-cropping cultivation in southern rice areas.The main results of this study are as follows:1.The annual cumulative emissions of CO₂,CH₄ and N₂O greenhouse gases and the comprehensive warming potential are all significantly different.The order of cumulative annual CO₂ emissions of different planting patterns is:rice straw>rice rice potato>rice rice b>rice Rice fertilizer>Rice and rice oil>Rice and rice leisure,compared with the control rice and rice leisure,the treatments increased by 44.15%,37.79%,13.31%,6.71%,and3.27%respectively.After 34527.05（kg/hm2）,rice and rice oil was the least,at 24735.06（kg/hm2）.The annual cumulative emissions of CH₄ greenhouse gases are:rice rice potato>rice rice bud>rice rice fertilizer>rice rice straw>rice rice oil>rice rice leisure,compared with the control rice rice leisure,each treatment increased by 99.78%,62.44%,45.15%,36.03%,1.93%,among the treatments,rice and potato emissions were the highest,reaching1050.78（kg/hm2）,and rice and rice oil were the least,536.1（kg/hm2）.The order of annual cumulative N₂O greenhouse gas emissions is:rice rice potato>rice rice bud>rice rice oil>rice straw>rice rice fertilizer>rice rice leisure,compared with the control rice rice leisure,each treatment increased by 60.67%,33.11%,15.42%,9.38%,0.96%,among the treatments,the highest rice and potato emissions reached 701.31（kg/hm2）,and the lowest rice and rice oil was 440.7（kg/hm2）.Based on the potential of different planting patterns,the potentials of temperature increase for each treatment are as follows:rice rice potato>rice rice bud>rice straw>rice rice oil>rice rice fertilizer>rice rice idle,and the control rice idle phase Compared with each treatment,they increased by 56.59%,33.79%,15.93%,13.42%,and6.21%respectively.Compared with the control of rice paddy,each treatment has a significant increase in the annual greenhouse gas emission warming potential.2.In soil aggregates,generally 0.25-2mm>2mm>0.053mm>0.25～0.053mm.As the depth of the soil layer increases,the average mass radius（MWD）and the average geometric radius（GMD）of each agglomeration show a downward trend;the trend of MWD and GMD between treatments is generally consistent.From the analysis of the average content of MWD and GMD,from the perspective of the average mass radius（MWD）,in the winter season,rice and potato are the highest at 4.27g.kg^-1,an increase of 26.71%compared with the control;rice and rice fertilizer is the lowest 3.05g.kg^-1,which is 10.49%lower than the control.In the early rice period,rice straw was the highest at 2.95g.kg^-1,an increase of19.92%compared with the control;rice and rice bud was the lowest at 2.31g.kg^-1,a decrease of 6.49% compared to the control.In the late rice period,the highest rice paddy was2.37g.kg^-1,an increase of 19.69%compared with the control;the lowest rice fertilizer was1.95g.kg^-1,a decrease of 1.54%compared with the control.From the perspective of the average geometric radius（GMD）,in the winter cropping season,rice and rice buds were the highest at 2.67g.kg^-1,an increase of 9.43%compared with the control;rice and rice oil was the lowest at 2.1g.kg^-1,which was lower than the control 16.19%.In the early rice period,rice straw was the highest at 2.12g.kg^-1,which was an increase of 9.28%compared with the control;rice and rice was the lowest at 1.79g.kg^-1,a decrease of 8.38%compared to the control.In the late rice period,rice and potato were the highest at 1.82g.kg^-1,an increase of13.04%compared to the control,and rice and rice oil was the lowest at 1.6g.kg^-1,a decrease of 0.63%compared to the control.Overall,the rice,potato,rice,straw,rice,rice,and rice buds of each treatment obviously promoted the content of the average mass radius（MWD）and the average geometric radius（GMD）of the aggregate to a certain extent.3.Overall,with the deepening of the soil layer,the total organic carbon content of the soil showed a downward trend.From the point of view of soil total organic carbon（SOC）content,the highest cropping rate in winter season was rice and rice,which was 33.57g.kg^-1,an increase of 11.31%compared with the control;the lowest SOC content in rice and rice fertilizer was 26.7g.kg^-1,which is 12.96%lower than the control.In the early rice period,the highest rice oil was 31.59 g.kg^-1,which was an increase of 0.61%compared with the control;the SOC content of the rice fertilizer was the lowest,27.2 g.kg^-1,which was 15.44%lower than the control.In the late rice period,the highest SOC content of rice paddy reached 36.89g.kg^-1,an increase of 25.73%compared with the control,and the lowest SOC content of rice oil was 29.22 g.kg^-1,a decrease of 0.41%compared with the control.4.Comprehensive comparison,with the deepening of the soil layer,the content of soil active organic carbon showed a downward trend.From the point of view of soil active organic carbon content,winter rice season had the highest rice and rice oil at 1.3 g.kg^-1,an increase of 17.24%compared with the control;rice and rice had the lowest 1.05 g.kg^-1,a decrease of 10.48%compared to the control.In the early rice period,rice straw was the highest at 1.2 g.kg^-1,an increase of 4.35%compared to the control,and rice fertilizer was the lowest at 0.95 g.kg^-1,a decrease of 21.05%compared to the control.In the late rice period,the highest rice-potato potato reached 1.35 g.kg^-1,an increase of 4.65%compared with the control,and the lowest rice-potato,1.01 g.kg^-1,a decrease of 27.72% compared with the control.