3.3.1. Spatial Autocorrelation Test
The spatial autocorrelation test results given in
Table 5.
The above results show that after including economic factors, each matrix shows a higher spatial autocorrelation relationship. So, it can be recognized that there has indeed been a spatial correlation between the values of agricultural ecological efficiency among provinces, which has been embodied in the adjacency correlation, provincial capital city correlation, and per capita GDP. In terms of geographical distance alone, since 2009, there has been no spatial correlation between provinces, which is consistent with the results of the kernel density test above, but economic distance has extended the correlation between provinces over time.
Referring to the previous research results, it has been found that most studies believe that there is a significant spatial autocorrelation relationship between the agricultural ecological efficiency values in China over the years, and the
p-value of most years is less than 0.01, the spatial correlation coefficient is high, and the spatial autocorrelation relationship is strong. However, this study believes that the reason for this may be that the author used the method of calculating the cross-sectional data of each year separately when calculating the value of agricultural ecological efficiency. As a non-parametric model, the DEA model calculates the relative value within the sample based on the input and output data of the sample. In addition, in this study, the efficiency value of each year has been calculated in the form of cross-sectional data, and the test results are similar to those of previous studies. In addition, many scholars have found that China’s agricultural eco-efficiency values generally show an
α divergence trend [
8,
9], indicating that in terms of time trends, the differences in China’s agricultural eco-efficiency values are expanding. Therefore, the study believes that
Table 5 may more truly reflect the spatial correlation of China’s agricultural ecological efficiency values.
3.3.2. Analysis of Spatial Durbin Model
Using the statistical software Stata 16.0, based on the general spatial model constructed above (using the economic distance matrix), the Wald test was firstly carried out. The test results rejected the null hypothesis at the 1% level, indicating that it cannot be simplified to a spatial error model (SEM) or a spatial autonomic model. A regression model (SAR). The LR test results show that compared with the spatial autoregressive model, the spatial error model, and the spatial autocorrelation model (SAC), the log-likelihood value of the spatial Durbin model is higher, and the AIC and BIC values are lower. The LR test results also point to the Durbin model. Finally, the Hausman test has been used to determine whether the fixed effect or random effect has been used. The Hausman test obtains a chi-square statistic of 46.9, and the null hypothesis is rejected at the 1% level; that is, from a purely technical point of view, the fixed-effect model should be selected. However, the study finally chooses to take the regression results of the random-effects model as the criterion. The specific reasons include the following points:
First, there is currently no consensus in the academic community on the selection, use of random-effects models, and fixed-effects models. For example, when dealing with sequence data with a large N, random effects are more effective [
25]. This view is also confirmed in the papers of [
26,
27]. Second, in the regression, this paper first used ordinary least squares (OLS), random effect model, and fixed-effect model, and then carried out the regression of the spatial Durbin random effect model and the spatial Durbin fixed-effect model. The comparison found that the random effect and the regression results of the model and the ordinary least squares method have a close match. The robustness test indicates that the regression results of the random effect model are more stable.
From a national perspective, the agricultural ecological efficiency of neighboring provinces has a positive spatial spillover effect on the agriculture ecological efficiency of the region, which has also been reflected in the eastern and western regions, while the provinces in the central region have positive spatial spillover effects from neighboring provinces but it is not obvious.
In
Table 6 the agricultural fiscal expenditure has a significant negative impact on the agricultural ecological efficiency of the region at a level of 5%, which is consistent with the research results of many scholars. However, the surrounding areas have a significant positive spatial spillover to the province’s AEE at the 1% level.
Agriculture’s environmental fiscal expenditures have a significant positive impact on improving the agricultural ecological efficiency in the region, but environmental governance in adjacent areas has a significant negative impact on the region.
The financial expenditure on agricultural science and technology has a significant positive impact on the region at the level of 1%, and the financial support for science and technology in the surrounding areas also has a significant positive impact on the finances of the region at the level of 1%, and the impact is greater than that of the region, indicating that the support for science and technology has a significant positive impact. Good positive externalities. At the same time, the marginal impact of scientific and technological expenditures on agricultural ecological efficiency is the largest among the various financial expenditures in the study, indicating that the scientific and technological development of agriculture advocated by China’s agricultural development strategy has good returns and is still in the stage of rising income. It has a large room for growth. When comparing the proportion of the financial expenditure on science and technology in each region to the total financial expenditure of the region, it is found that the ratio of the eastern region is 3.41%, the ratio of the three regions is the highest, and the lowest is 1.11% of the western region.
The financial expenditure on agricultural education has no significant impact on the agricultural ecological efficiency of the province, and the education financial expenditure in the surrounding provinces has a significant negative impact on the agricultural ecological efficiency of the province.