## 2 Materials and Methods
### Methodologies
#### 2.3.5 Ecosystem Dis-Services Valuation Model (DESV)
The specific coefficients are shown in Table 3.  
(2) Water consumption valuation model  
The value of water consumption can be calculated by the water storage cost method of the available reservoir [64]. \[V_{water}=W\times R\times C_{w} \tag{9}\]  
\(V_{water}\) represents the negative value of water consumption; \(W\) is the water consumption for agricultural irrigation (m\({}^{3}\)); \(R\) is the agricultural water consumption rate (%), with a value of 35%; \(C_{w}\) is the storage cost of the reservoir (1.17 CNY/m\({}^{3}\)) [65]. (3) Pesticide pollution valuation model  
During the use of pesticides in China, 20-40% of the pesticides are released into the air and 40-60% fall on the ground, which results in the ineffective use of pesticides [66]. In this study, the value of 39.8% was taken as the pesticide utilization rate, according to the Ministry of Agriculture and Rural Affairs of China [67]; the average pesticide price was 30,000 CNY/t, and the negative value of pesticides was estimated from the above data. \[V_{pesticide}=S_{P}\times(1-n)\times P_{P} \tag{10}\]  
where \(V_{pesticide}\) means the negative value of pesticide pollution; \(S_{P}\), \(n\) and \(P_{P}\) represent the pesticide usage (t), pesticide utilization rate, and pesticide price (CNY/t), respectively. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type** & **CL** & **FL** & **OL** & **GL** & **WB** & **UL** \\ \hline Carbon emission coefficient & & & & & \\ (t-hm\({}^{-2}\)-a\({}^{-1}\)) & 0.3190 & \(-\)0.6036 & \(-\)0.2100 & \(-\)0.2887 & \(-\)0.2380 & \(-\)0.0005 \\ \hline \hline \end{tabular}  
Notes: The coefficients in the table refer to the research results of [60; 61; 62].  
\end{table} 
Table 2: Carbon emission coefficient of different land-use types. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & **Units** & \
\begin{tabular}{c} **Standard Coal** \\ **Coefficient (tce/t)** \\ \end{tabular} &
\begin{tabular}{c} **Carbon Emission** \\ **Coefficient (tce/t)** \\ \end{tabular} \\ \hline Raw coal & t & 0.7143 & 0.7559 \\ Coke & t & 0.9714 & 0.855 \\ Gasoline & t & 1.4714 & 0.5538 \\ Kerosene & t & 1.4714 & 0.5714 \\ Diesel fuel & t & 1.4571 & 0.5921 \\ Fuel oil & t & 1.4286 & 0.6185 \\ Natural gas & t & 1.33 & 0.4483 \\ Liquefied petroleum gas & t & 1.7143 & 0.5042 \\ \hline \hline \end{tabular}  
Notes: Carbon emissions coefficient referenced from [63].  
\end{table} 
Table 3: Carbon emissions coefficients of energy consumption. (4) Fertilizer loss valuation model  
While increasing crop yield, chemical fertilizers also bring about many ecological and environmental problems, such as water eutrophication [68], soil pollution and acidification [69], etc. The value of water eutrophication caused by the loss of chemical fertilizer is difficult to calculate and quantify. This study only considers the value of chemical fertilizer loss and calculates the negative value of chemical fertilizer application. \[V_{fertil}=S_{F}\times(1-r)\times P_{F} \tag{11}\]  
where \(V_{fertil}\) means negative value of fertilizer loss; \(S_{F}\) denotes fertilizer usage (t); \(r\) and \(P_{F}\) represent the fertilizer utilization rate with a value of 39.2% [67] and fertilizer price of Ningde City with an average value of 3600 CNT/t, respectively. (5) Agricultural plastic-film residual pollution valuation model  
China is a big agricultural country, with the largest user of plastic-film in the world. However, plastic-film mulching technology not only increases the effective output of crops, but also leads to the continuous accumulation of plastic-film residues in the soil. The eco-environmental problems caused by plastic-film residues have become increasingly prominent, such as reducing soil fertility and affecting the growth of crops, etc. [70]. According to the survey, the residual rate of agricultural plastic film in Ningde City reaches an average of 40%; the cost of manual treatment and mechanical treatment are 8292.5 CNY/t and 2421.4 CNY/t, respectively, with an average value of 5356.9 CNY/t.