| As one kind of paddy cultivation models,the rice-crayfish co-culture has been developed rapidly in southern provinces（cities）of our country for its high economic benefit.Hubei Qianjiang is the earliest county（city）where large areas of application and popularization of the rice-crayfish co-culture are started,and it is in the forefront of the development of our rice-crayfish industry.In this study,the cultivation model of rice-crayfish co-culture in Qianjiang was taken as the object.Firstly,three different utilization models were tested,namely rice-crayfish co-culture（RC）,rice monoculture（RM）and crayfish intensive farming（CIF）,the resource utilization efficiency,energy input and energy efficiency of three different paddy fields were studied.Secondly,a questionnaire survey was carried out on farmers of rice-crayfish co-culture in Qianjiang city,and 209valid questionnaires were obtained to analyze the characteristics of energy input and energy efficiency utilization of this mode.Finally,through data envelopment analysis（DEA）,optimization suggestions are put forward for the energy input of this model to promote the green and healthy development of this model.The main findings are as follows:（1）The analysis of resource utilization efficiency of different paddy utilization modes showed that the photothermal resource utilization efficiency of RC was not significantly different from that of CIF.The precipitation use efficiency of RC was higher than that of the other two modes,and the total water production efficiency was not significantly different from that of CIF type,but it was significantly higher than that of CIF mode.RC nitrogen（N）partial productivity was lower than CIF and higher than RM.The output of N and P of the three modes of runoff was lower than that of runoff N and P,and the input output of RC runoff N and P was the highest.（2）The energy analysis of different paddy utilization modes showed that RC had the most energy input,about 2 times of RM and 1.2 times that of CIF;in RC,feed input accounted for the highest proportion of energy,but fertilizer input was lower than RM,indirect energy input of the three agricultural modes was higher than direct energy input,RC net energy gain was basically the same as that of rice monocropping mode,but the energy yield was 35%of RM,and CIF net energy gain was negative.（3）The results of the characteristics and economic benefits of the questionnaire farmers showed that the practitioners of rice-crayfish co-culture were older,mostly over 45years old,and nearly half of them were over 65 years old,but the planting period was longer.This model has high economic benefits,and the income of crayfish is much higher than that of rice,about 2.5 times.（4）The analysis of energy input in rice-crayfish co-culture in Qianjiang city showed that crayfish feed had the largest energy input(26839MJ·ha-1),accounting for about 42%of the total energy input,followed by irrigation water and fertilizer;The average input of non-renewable energy and the input of renewable energy was 20.41 GJ·ha-1 and 43.93GJ·ha-1,accounting for 32%and 68%of the total input,respectively.The net energy gain of this model is 85.95 GJ·ha-1 and the energy utilization rate is 2.56.（5）Through DEA,the efficiency test and optimization of the energy input of rice-crayfish co-culture in Qianjiang city were carried out,and the results were:63%of the farmers participating in the survey had an efficiency value of less than 0.75,and only about20%of the farmers who achieved the best input energy were achieved.If the research recommendations are followed in the production process,the energy input per hectare can be reduced by 50%,about 32397 MJ,feed input can be reduced by about 1200 kg·ha-1,and irrigation water input can be reduced by about 7000 m3·ha-1.In summary,the rice-crayfish co-culture was superior to the rice monoculture and the crayfish intensive culture in terms of resource utilization and energy output,and was suitable for promotion in suitable areas.The development of rice-crayfish co-culture in Qianjiang city has played an important role in stabilizing rice grain output and increasing farmers’income.however,in the current actual production process,the phenomenon of excessive energy input is widespread,according to the energy input optimization of this experiment,it is recommended to appropriately reduce the excessive energy input items such as feed and water resources,reduce the negative impact on the environment,promote the healthy development of the model,and improve the economic benefits of farmers. |
