3.4.4. Analysis on the Adjustment of Efficiency Input in Western China

In Table 3, the production efficiency of greenhouse tomatoes in Inner Mongolia, Shaanxi, Gansu and Qinghai is not effective in western China. The adjustment range is shown in Figure 5b. The adjustment ranges of six input factors of greenhouse tomatoes in Inner Mongolia are 65.11%, 65.11%, 36.47%, 65.11%, 48.38%, and 60.68%, respectively, including material and service cost, number of working days, seed cost, fertilizer cost, farmyard manure cost, and pesticide cost. The adjustment ranges of six input factors of greenhouse tomatoes in Shaanxi Province are 84.85%, 84.85%, 43.66%, 84.85%, 61.10%, and 58.36%, respectively. The adjustment ranges of six input factors of greenhouse tomatoes in Gansu Province are 69.24%, 70.53%, 77.70%, 78.09%, 78.09%, and 78.09%, respectively. The adjustment ranges of six input factors of greenhouse tomatoes in Qinghai Province are 62.05%, 72.32%, 88.69%, 87.12%, 28.83%, and 95.84%, respectively.

In general, there exist some problems of excessive investment in Inner Mongolia, Shaanxi, Qinghai, and Gansu, resulting in waste of energy and environmental pollution. In the western region, the excessive input of pesticides in Shaanxi Province is 41.64%. The excessive input of fertilizers in Inner Mongolia is 39.32%, while the excessive input of pesticides is 34.89%.

#### **4. Conclusions and Policy Implication**

This paper uses a DEA model to analyze the overall technical efficiency (OTE), pure technical efficiency (PTE), and scale efficiency (SE) of greenhouse tomatoes, greenhouse cucumbers, greenhouse eggplants, and greenhouse peppers from the perspective of greenhouse vegetable production efficiency. According to different efficiency values of greenhouse vegetables, we put forward some suggestions to adjust the different production efficiency. The main conclusions are as follows:

• In the production of greenhouse tomatoes and cucumbers in China, the loss of PTE may lead to inefficiency in most provinces. For greenhouse tomatoes, among the 17 inefficient provinces, the PTE of 11 provinces is lower than the SE. For greenhouse cucumbers, among the 14 inefficient provinces, the PTE of 9 provinces is lower than the SE. The results show that the government should pay more attention to the improvement of the PTE of greenhouse tomatoes and cucumbers.


Based on the above analysis, we put forward some suggestions for the different characteristics of the efficiency of greenhouse vegetables in different provinces. The suggestions are as follows:


In the next study, we plan to study the change of greenhouse vegetable production efficiency from the perspective of time series and space in China. It is planned to use the DEA model and Tobit model to explore the influencing factors of greenhouse vegetable production efficiency, in order to make a contribution to the development of green and sustainable agriculture.

**Author Contributions:** All authors contributed to this study. J.R. and Y.L. formulated the study design. J.R., Y.S., Y.L., and Y.W. conceived and designed the research methodology. X.J., J.R., and Y.L. collected and analyzed the data. J.R. and Y.L. finalized the paper.

**Funding:** This work was supported in part by the National Natural Science Foundation of China under Grants 71703122, 71973106, and 71531002, the China Ministry of Education Social Sciences and Humanities Research Youth Fund Project under Grant 16YJC630102, the Science and Technology Plan Projects of Yangling Demonstration Zone under Grant 2016RKX-04, the Fundamental Research Funds for the Central Universities under Grant 2018RWSK02, the Key Research and Development Program of Shaanxi under Grant 2019ZDLNY07-02-01, and the National College Students' Innovation and Entrepreneurship Training Program under Grant 201910712075.

**Acknowledgments:** We thank the National Nature Science Foundation of China, China Ministry of Education Social Sciences and Humanities Research Youth Fund Project, Natural Science Basic Research Project in Shaanxi Province, Science and Technology Plan Projects of Yangling Demonstration Zone, Fundamental Research Funds for the Central Universities, Key Research and Development Program of Shaanxi and National College Students' Innovation and Entrepreneurship Training Program for funding the research.

**Conflicts of Interest:** The authors declare no conflict of interest.
