4.1. Simulation Analysis on Complex Network Considering Social Preference
According to constraints of the replication dynamic equations and evolutional stable strategies, the computer simulation technology based on complex network and MATLAB software were used to conduct numerical simulation experiments on the evolution process of green production behavior of agricultural production operators. Thus, the impact of profit, cost and different social preferences on the evolution process of agricultural green production networks are mainly explored.
Assuming that the initial time of the evolution process would begin at T = 0 and the end time T is 100, the initial scale-free network is 100 nodes, among which 20 nodes are denoted as new agricultural operators and the remaining 80 nodes are denoted as traditional farmers. The location and neighbors of agricultural production operators on the network are randomly generated, and the specific simulation experiment steps are as follows:
Step 1: T = 0, the agricultural green production networks and set parameter values are initialized.
Step 2: T = 1, the game starts. The agricultural production operators on the network randomly select nodes of neighbors for profit comparison. If their profit is not less than that of neighbors, they would continue to adopt their original strategy at the next round of game. Otherwise, they would learn from neighbors and update their strategy with certain probability.
Step 3: T = 2, repeat Step 2 for the next round until the end of the game.
In this section, four simulation experiments are conducted to further analyze the evolution process of agricultural green production behavior by agricultural production operators in the scenarios of being without social preference, with competitive preference, with the differential aversion preference, and with social welfare preference, respectively. The parameters are set as shown in
Table 13.
The values of preferences and in these simulation experiments are as follows: being with competitive preference: , being with differential aversion preference: and being with social welfare preference: .
In the first scenario, the cost of agricultural production operators adopting the strategy of green production is significantly greater than its corresponding extra income, and the evolution results are shown in
Figure 2a–d, which represents the scenario of being without social preference, being with differential aversion preference, being with social welfare preference, and being with competitive preference, respectively.
It can be seen from
Figure 2 that when the cost of agricultural production operators adopting the strategy of green production is much higher than the extra income gained by the green production, the evolution of the density of the agricultural green production cooperator would be finally tend to be 0 in these four scenarios. It shows that new agricultural operators and traditional farmers will ultimately adopt the strategy of non-green production regardless of social preference. This is because even though the agricultural production operators have social preferences of green production, the utility brought by these social preferences is much lower than the strategy of non-green production. Therefore, the agricultural production operators will gradually adopt the strategy of non-green production after several times of game by learning from their neighbors. Thus, the cooperation of agricultural green production will collapse.
Furthermore, when comparing the behaviors of these two types of agricultural production operators, it can be seen that new agricultural operators made several attempts to adopt the strategy of agricultural green production in the evolution process, while traditional farmers formed a consistent stable strategy of non-green production earlier. This is mainly due to the well foundation and willingness of new agricultural operators for green production. Therefore, they should be the main target of green agricultural development policies.
The second scenario shows that the cost of adopting the strategy of green production is close to the corresponding extra profit. And the evolution results of these four different preferences are shown in
Figure 3a–d, which represents the agricultural production operators on the network are without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
It is seen from
Figure 3a that when the cost of adopting the strategy of green production is nearly close to the corresponding extra income and the agricultural production operators are without social preference, then the state of cooperative density of 1 cannot be reached. However, when the agricultural production operators are with the differential aversion preference, the density of agricultural green production cooperator could evolve to a stable state of 1 after 50 times of evolution, which could be seen in
Figure 3b. While the agricultural production operators are with social welfare preference, the density of agricultural green production cooperator would fluctuate smoothly between 0 and 1, with the trend of approaching to be 1, which is shown in
Figure 3c. When the agricultural production operators are with competitive preference, the density of agricultural green production cooperator would evolve to be 1 before 30 times, and then gradually decreased nearly to be 0, which is illustrated in
Figure 3d. Thus, it can be concluded that social preference and differential aversion preference could promote the agricultural green production networks of agricultural production operators, and the effect of differential aversion preference is more significant.
Additionally, when compared with the first scenario, it is found that in the second scenario, the behavioral evolution trend of these two types of agricultural production operators is basically consistent.
The third scenario shows that the cost of adopting the strategy of green production is less than the extra income gained by the green production. And the evolution results of these four different preferences are shown in
Figure 4a–d, which represents the agricultural operators on the network are without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
It is seen from
Figure 4 that as long as the cost of adopting the strategy of green production is less than the extra income gained by the green production, the density of agricultural green production cooperator tends to evolve to be 1, regardless of social preferences of agricultural production operators. However, in contrast with other preferences, agricultural production operators with competitive preference would cooperate in agricultural green production more quickly. This is because these agricultural production operators with competitive preference are more likely to learn from neighbor’s strategies by comparing profits.
Moreover,
Figure 4 shows that traditional farmers are more likely to form stable strategy of agricultural green production than new agricultural operators, indicating that traditional farmers are more sensitive to the profits brought by agricultural green production.
4.2. Simulation Analysis on Complex Network Considering Governments’ Strong Reciprocity
In this section, five simulation experiments are conducted to further analyze the evolution process of green production behavior considering governments’ strong reciprocity by agricultural production operators. The simulation parameters are shown in
Table 14. The preference value and experimental process are consistent with
Section 4.1.
In the fourth scenario, the cost of agricultural production operators adopting the strategy of green production is significantly greater than the extra income, and the government’s strong reciprocity is small. The corresponding evolution results are shown in
Figure 5a–d, which represents the scenario of four different preferences, that is without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
Comparing
Figure 2 in
Section 4.1 with
Figure 5, it can be seen so long as the cost of agricultural production operators adopting the strategy of green production is much higher than the extra income gained by the green production, and the governments’ strong reciprocity is low, then the density of agricultural production cooperator would evolve to be 0 in these four scenarios. This implies that agricultural production operators would adopt the strategy of agricultural non-green production after a few times of game very quickly. In the four scenarios, the net profit of agricultural production operators adopting the strategy of agricultural green production is negative, and even if the government adopt the strategy of strong reciprocity, there Is still not enough profit to compensate for cost. As such, these two types of agricultural production operators’ cooperation in agricultural green production will collapse.
In addition, compared with new agricultural operators, traditional farmers are more likely to reach a consistent stable strategy of non-green production, which is similar in the first scenario.
As the level of government’s strong reciprocity is slightly enhanced in the fifth scenario, the evolution results are illustrated in
Figure 6a–d, which represents the scenario without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
By comparing
Figure 5 and
Figure 6, it can be seen that the evolution result of the density of agricultural production cooperator would be better with the increase in governments’ strong reciprocity. When agricultural production operators have a differential aversion preference, the density of agricultural production cooperator could reach a stable state of 1. When the agricultural production operators have a social welfare preference, the density of the agricultural production cooperator would fluctuate in the range of 0 to1. While agricultural production operators are with competitive preference and without social preference, the density of agricultural production cooperator would decrease to be 0 both at nearly 10 times and 50 times of the game, respectively. Thus, differential aversion preference would promote agricultural production operators to adopt the strategy of agricultural green production, especially in the strong reciprocity policy of the government their agricultural green production networks would form more quickly.
Additionally,
Figure 6 also shows that the behavioral evolution trend of these two types of agricultural production operators is basically consistent, which is similar to the second scenario.
Then, the degree of governments’ strong reciprocity is slightly enhanced based on the evolution of
Figure 6, and the results are shown in in
Figure 7a–d, which show the evolution results in the scenario of four different preferences, that is without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
Figure 7 shows that when the governments have strong reciprocity, the density of agricultural production cooperator in the above four scenarios would all evolve to a stable state of 1. Furthermore, if agricultural production operators have a social preference, then green agriculture production network could emerge even faster, especially the traditional farmers are more likely to form stable strategy of agricultural green production. This suggests that traditional farmers are more sensitive to the governments’ strong reciprocity by agricultural green production.
Comparing
Figure 5 and
Figure 6 with
Figure 7, it can be seen that when the cost of agricultural green production is significantly greater than the extra income obtained from agricultural green production, governments’ strong reciprocity would significantly affect the agricultural green production density of cooperator. When the government reciprocity continues to be strengthened, no matter whether agricultural production operators have a social preference, it would all achieve the stable situation of agricultural green production cooperative density of 1.
Thus, it could be concluded that when the cost of adopting the strategy of agricultural green production (e.g., adoption of agricultural green production technology and development equipment, biological insecticides, etc.) are higher than the extra benefit of agricultural green production, governments’ strong reciprocity can play a role. Governments will reward agricultural production operators who adopt green production strategies and punish those adopting the strategy of non-green production for their negative behavior on the environment. Under the effect of governments’ strong reciprocity, even if the net benefit of agricultural green production is low, many agricultural production operators could be encouraged to adopt the strategy of agricultural green production, and influence their neighbors on agricultural production network, so as to gradually promote the emergence of agricultural green production cooperator.
The cost of adopting the strategy of agricultural green production is relatively similar to the corresponding extra income, and the evolution of these four different preferences are shown in
Figure 8a–d, namely being without social preference, being with differential aversion preference, being with social welfare preference, and being with competitive preference, respectively.
Figure 8 shows that when the cost of the agricultural production operators adopting the strategy of agricultural green production nearly equals to the extra income, with the strong reciprocal intervention of government, the stable state of agricultural green production cooperative density of 1 can be reached regardless of the preference of agricultural production operators. Among them, the density of agricultural green production operator can reach to a stable state of 1 after 80, 30, 30 and 22 times of the game under four different preferences of being with differential aversion preference, being with social welfare preference, and being with competitive preference, respectively.
On the basis of
Figure 8, the degree of governments’ strong reciprocity is increased, and the evolution results of four different preferences are shown in
Figure 9a–d, which, respectively, represent the evolution results of agricultural production operators on the network without social preference, with differential aversion preference, with social welfare preference, and with competitive preference, respectively.
It can be seen from
Figure 8 that if the government’s strong reciprocity is increased on the basis of
Figure 8, no matter whether agricultural production operators have preferences or not, the density of agricultural green production cooperator will reach the stable state of 1 faster than
Figure 8. When the intensity of governments’ strong reciprocity is enhanced, agricultural production operators without social preference, with differential aversion preference, social welfare preference, and competitive preference would reach to the stable state after 55, 22, 30 and 18 cycles, respectively.
Comparing
Figure 4,
Figure 8 and
Figure 9 in
Section 4.1, it can be seen that when the cost of adopting the strategy of agricultural green production is relatively close to the extra profit, the governments’ strong reciprocity could promote the diffusion of agricultural green production networks, even if the level of governments’ strong reciprocity is low. Then, if the governments’ strong reciprocity is strengthened, the density of agricultural green production cooperator with different preferences could reach to be 1 more quickly.