| Green and efficient agricultural machinery is a key developmental trend for future agricultural machineries.The primary task of green and efficient agricultural machinery is to properly evaluate the current mechanized crop production systems and its performances of green index and efficiency.Therefore,it is of paramont importance to precisely define and study the mechanized crop production system,identifying its boundaries and providing indicators of green and efficiency production.Rice-wheat rotation is widely distributed in the South regions of China agriculture.However,differed geology,soil and climate has its’ effects on the production systems,and thus mechanization and mechanized field operations vary from place to place.The widely differed mechanized rice-wheat production systems did contribute to the complexity and difficulty of system evaluation on the green and efficiency.In this work,mechanized rice-wheat roation in Jiangsu Province was selected for system evaluation.Scientific problems belonging to 3 scopes were first identified and defined,i.e.systematic evaluation of the overall mechanized system,evaluation on some key mechanized field operations,and evaluation on the effects of key mechanized field operations.The definition of these 3 scopes of research allow us to effectively and precisely evaluate the targeted problems.The methods adopted for evaluation varied according to the scope of focused problem.In the systematic scope I selected energy evaluation method.Each inputs constituting the mechanized system were transformed with standard treatments into energy units.Also,similar transformation into energy value were made to key mechanized field operations.In the scope of effects evaluation on key field operation,stubble and straw states left by mechanized harvesting were evaluated.Multiple indices of straw information were acquired and used as a comparison with energy evaluation.So that different evaluation methods can be comparied for its effectiveness.The main research contents and results of this paper are as follows:(1)Taking the whole system of mechanized rice-wheat rotation system in Jiangsu Province as the research object,according to its agricultural input and output,the relevant parameters such as labor input,mechanized input,agronomic input,and total output of wheat and rice were investigated,and a survey was conducted.The system’s energy flow evaluation system was constructed,and the results showed that from2015 to 2019,the total energy input of the entire system decreased by 8.32%,while the total energy output increased by 5.5%.At the same time,the energy return rate of the entire system increased from 4.13 to 4.71,an increase of 14%;energy productivity increased from 2.08 to 2.36,an increase of 13.46%,showing a steady growth trend;the mechanization index increased from 0.51 to 0.54,an increase of 5.88%.The mechanization index has a linear function relationship with the energy return rate and energy productivity.The energy return rate and energy productivity increase with the increase of the mechanization index.(2)Conducted field investigation and research on the whole mechanized production system of rice-wheat rotation in Sihong Agricultural Base,and recorded the technical matching of various agricultural machinery in the mechanized links of harvesting,plowing,field preparation,field management,seeding,etc.,testing and statistics The labor input,machine efficiency and fuel consumption,seed pesticide and fertilizer consumption of agricultural machinery in the working process are analyzed.Finally,the energy evaluation method is used to quantify the energy productivity of each mechanization process.Finally,it is concluded that in each mechanization process,indirect energy The investment has increased significantly with the increase in the number of processes,thus increasing the total investment in mechanization.For example,in the mechanization of harvesting and stubble,the indirect energy consumption in the cost of mechanized input accounts for 56%-64%of the mechanized input in the wheat harvesting stage,and 76%-79% in the rice harvesting stage.The final evaluation of the energy productivity of various mechanized production modes found that the energy productivity is the highest in the operation mode of all-fed high-stubble crushing(FHC)+ no-till(NT)in wheat production,reaching 2.92;in rice production Under the operation mode of half-feeding(H)+ no-tillage foaming field deep spinning(DS),the energy productivity is the highest,reaching 3.57.(3)At the plot scale of the Sihong Agricultural Base,around the issue of the stubble state after the harvest of rice and wheat,first divide the original stubble field into standing stubble and broken straw,and extract the parameters separately,aiming at the quality of the standing stubble.Multi-dimensional information parameters such as distribution,standing stubble silhouette coverage,quality distribution of broken straw,and number of stacked layers,respectively,use in-situ grid sampling and weighing method,flat plate leveling image method,background plate image method,broken straw screening method,Methods such as manual observation and counting methods have been used to study the state of the original stubble field under different harvesting methods in the harvesting process,and it is concluded that compared with standing stubble,the distribution of broken straw can better reflect the distribution of the overall quality of straw;the distribution of the number of stacked layers of straw The similarity of broken straw quality distribution is high,up to 0.9;the standing stubble silhouette coverage distribution has a certain image similarity with the standing stubble quality distribution,but the overall similarity level is low,varying in the range of 0.4-0.5,but it can be passed through the standing stubble.The profile coverage distribution is compared with the local change of the standing stubble quality distribution to determine whether the erect state of the local standing stubble has changed.Comparing the stubble status of wheat with high stubble harvest and low stubble harvest,it is found that while the high stubble produces more broken straw,the distribution of the broken straw is more concentrated;at the same time,the straw stubble under the high stubble harvest mode is more stable.Lodging reveals more clearly the track trajectory of the harvester.Comparing rice with full-fed low stubble,full-fed high-stubble harvesting and synchronous grass shredding with half-feeding harvesting,it is found that the full-fed high-stubble harvesting synchronous crushing can achieve a stubble elimination effect similar to that of full-fed low stubble;The distribution of broken stubble under the simultaneous crushing mode of high stubble harvesting is more concentrated;the quality distribution of standing stubble and broken straw under the half-feeding harvesting mode are different from the former two,and the overall quality level of the standing stubble with half-feeding is lower.;The broken straw gathers on half of the cutting width.The standing stubble lodging state in the half-feeding harvesting mode can better reflect the track trajectory of the harvester. |
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