Evaluation On Resource Utilization Efficiency Of Different Cropping Systems In Double Cropping Area Of North Central Hubei Province

Double cropping system is one of the main systems of crop production in Hubei Province,and its total area accounts for nearly 50%of the province.North central Hubei province is the main Double cropping area in Hubei Province,and it is in the north-south climate transition zone.In recent years,with the changes of climate and production conditions in north central Hubei province,the allocation of solar radiation and temperature resources during the season is unreasonable,the problem of soil and water resources unmatched crop growth demand is more prominent.It leads to the low annual crop yield,resource utilization efficiency and economic efficiency of some existing systems in the double cropping areas of north central Hubei province.In this study from 2017 to 2018,the field experiment focused on the characteristics of crop growth,solar radiation and temperature resource utilization,water and fertilizer resources utilization,economic benefits and greenhouse gas emissions of japonica rice-potato,japonica rice-green manure,japonica rice-rape,japonica rice-wheat,indica rice-none,indica rice-rape and indica rice-wheat in north central Hubei province.This study compares and analyzes these characteristics,and the main results and conclusions of this study are as follows:1.Crop productivity:The rice and annual yield of rice-wheat（japonica rice-wheat and indica rice-wheat）and japonica rice-potato systems is relatively high in Zaoyang and Jingmen,and the annual yield is higher than 16.5t/hm².The rice-rape（japonica rice-rape and indica rice-rape）system shows a higher annual biomass,and the annual biomass of the two systems in Zaoyang is higher than in Jingmen.The japonica rice-potato and japonica rice-green manure systems shows higher leaf area index and growth rate of rice in the rice season than the other systems.Based on the performance of various crop growth indicators,the rice-wheat（japonica rice-wheat and indica rice-wheat）and the japonica rice-potato systems show good advantages in the double cropping area of north central Hubei province.2.Utilization of solar radiation and temperature resources:The accumulated temperature use efficiency,solar radiation use efficiency and land use efficiency of rice-wheat（japonica rice-wheat and indica rice-wheat）and rice-rape（japonica rice-rape and indica rice-rape）systems are all at a high level,and the indica rice-wheat system has the best performance,reaching 94.2%,95.5%and 86.3%respectively.The temperature ratio（TR）of rice-wheat（japonica rice-wheat and indica rice-wheat）system is 0.30 and 0.29 in Zaoyang,respectively,slightly higher than in Jingmen.The grain temperature use efficiency of japonica rice-potato and japonica rice-wheat system increased by 30.0%and 27.7%,respectively,compared with that of indica rice-none system,and they give a certain advantage.The temperature potential productivity equivalent（TPPE）of the two crops in rice-wheat（japonica rice-wheat and indica rice-wheat）systems are at a relatively high level.And the temperature utilization rate,radiation utilization rate and grain solar radiation production efficiency of rice-wheat（japonica rice-wheat and indica rice-wheat）system in Zaoyang is higher than in Jingmen.Based on the performance of various temperature utilization and radiation utilization indicators,the rice-wheat（japonica rice-wheat and indica rice-wheat）system shows good advantages in the double cropping area of north central Hubei province.3.Utilization of water and fertilizer resources:The nitrogen accumulation of rice in japonica rice-green manure and rice-rape（japonica rice-rape and indica rice-rape）systems increased by 9.1%,8.4%and 2.9%in Zaoyang and Jingmen,respectively,compared with the indica rice-none system.The nitrogen partial productivity of japonica rice-green manure and indica rice-wheat system rice increased by 11.7%and9.3%respectively compared with the previous year;the japonica rice-green manure and indica rice-wheat system showed higher nitrogen partial productivity.The japonica rice-potato,japonica rice-green manure and rice-wheat（japonica rice-wheat and indica rice-wheat）systems increased soil organic carbon,total nitrogen and available potassium content to some extent.The annual water use efficiency of japonica rice-potato and japonica rice-wheat systems was the best,which was 29%and 33%higher than that of indica-none.Based on the performance of various fertilizer utilization and water utilization indicators,the rice-wheat（japonica rice-wheat and indica rice-wheat）,the japonica rice-potato and japonica rice-green manure systems show good advantages in the double cropping area of north central Hubei province.4.Greenhouse gas emissions:The japonica rice-potato,japonica rice-green manure and japonica rice-rape compared to indica rice-none system reduced by5.8%-10.9%of cumulative CH₄ cumulative emissions;japonica rice-potato and japonica rice-green manure reduced annual N₂O cumulative emissions compared to other systems.These two systems can reduce the global warming potential compared with the indica-none system,with a decrease of 3.0%and 5.4%,respectively.Based on the performance of greenhouse gas emissions indicators,the japonica rice-potato and japonica rice-green manure systems show good advantages in the double cropping area of north central Hubei province.5.Economic benefits:japonica rice-potato system of high-input and high-output,rice-wheat（japonica rice-wheat and indica rice-wheat）system of mid-input and mid-output show superior overall economic effects in the double cropping area of north central Hubei province,which was conducive to income increase.Based on the above evaluation indicators,the two systems of japonica rice-wheat and indica rice-wheat are relatively appropriate systems that have advantages over other systems in crop yield,solar radiation and temperature resource utilization,water and fertilizer resources use efficiency and economic benefits in north central Hubei Province.