1. Introduction
Climate warming, as an environmental consequence of rapid economic development, has posed a common threat to all mankind [
1]. In particular, agriculture has become the second largest source of greenhouse gas emissions after industry. According to data released by the World Bank, the CO2 generated by agricultural activities currently accounts for 20% of the total global CO2 emissions [
2].As one of the main input factors of agricultural production activities in China, agricultural land entails positive benefits, such as the production of agricultural products and the increase of the total output value of agriculture; however, it also releases a large amount of CO2 into the atmosphere [
3]. In the period 2000-2017, China's carbon emissions from agricultural land use (CEALU) increased from 52.3283 million tons to 76.1331 million tons, with an average annual growth rate of 2.25% [
4]. Even so, agricultural sources still account for 24% of the country's total greenhouse gas emissions [
5].In the context of achieving the objective of carbon dioxide emissions peak and carbon neutralization [
6], the exploration of the path towards carbon emission reduction in agricultural land use provides important insights on how to improve the capacity of agriculture to cope with climate change and to promote its sustainable development.
To explore the path of achieving carbon emission reduction in agricultural land use, numerous scholars have extensively assessed CEALU, achieving fruitful results. However, these studies mainly focused on the spatial pattern [
7,
8] and influencing factors of CEALU [
9,
10], the efficiency of carbon emissions [
11,
12], and the prediction of trends [
13,
14]. The optimization of land use patterns has not only impacted the export dynamics of crops like corn, sorghum, and wheat (which have decreased), but it has also influenced the export of barley, soybeans, and sunflowers (which have increased) [
15]. These shifts in trade patterns have further implications globally, contributing to greenhouse gas emissions [
16].
Some potential aspects that have not been studied in depth are the regional heterogeneity of farmland carbon emissions and the carbon reduction mechanism of High-standard farmland construction policies.High-standard farmland(HSF) is considered the concentrated contiguous cultivated land formed by rural land consolidation, supporting facilities, high and stable yield, pleasant ecological quality, strong disaster resistance and adapt to modern agricultural production and management mode [
17,
18].The High-Standard Farmland Construction(HSFC) policy is a strategic initiative in China aimed at promoting sustainable agricultural development and ensuring food security through land consolidation [
19].It involves various measures such as land leveling projects, irrigation and drainage projects, field road projects, farmland protection, and typical field remediation methods [
20,
21]. Of course in government, they prefer to call it Well-Facilitated Farmland. [
22].But for now, these two concepts are basically the same, both in content and mode. [
23,
24].Some scholars have also paid attention to the effect of high-standard farmland construction on CEALU. Land consolidation is a typical land use activity that also affects the carbon cycle and carbon pool storage of the project area, [
25], produces an extremely evident carbon effect [
26]. HSFC can effectively solve a series of problems, such as the fragmentation and low quality of farmland, the shortage of water conservancy facilities, and the deterioration of farmland environment [
27]. It also entails a significant fertilizer reduction effect [
28], and enhances the role of soil testing and formulated fertilization techniques in increasing fertilizer application efficiency [
29]. In addition, Liu et al. argued that eco-friendly, high-standard farmland construction by areas can effectively enhance the ecological effect of the engineering measures of "field, water, road, and forest", standing as an effective way to achieve the simultaneous improvement and target integration of ecological service and production functions [
30]. Moreover, Zhang et al. found that, after the completion of high-standard farmland construction, the area of cultivated land with ‘fully satisfied’ and ‘satisfied’ irrigation capacity increased by 7.91% and 19.64%, respectively, and that this improved irrigation capacity elevated the comprehensive grade of cultivated land quality by 0.25. In addition, they found that the area of cultivated land with ‘fully satisfied’ and ‘satisfied’ drainage capacity increased by 35.13% and 27.33%, respectively, and that this improved drainage capacity elevated the comprehensive grade of cultivated land quality by 0.31 [
31].
The abovementioned studies discusses the pathways for carbon emissions reduction in agricultural land and explores the impact mechanism of HSFC on carbon emissions from land use. This enriches the research system on carbon emissions from land use and lays a solid foundation for in-depth analysis. However, in certain circumstances, HSFC may bring about some unintended negative environmental impacts, posing challenges and issues in practical implementation [
32,
33]. For instance, the implementation of high-standard farmland construction may require substantial financial investment [
34], and the actual effects in different regions may vary due to factors such as local soil conditions, climatic characteristics, and agricultural management practices [
35,
36,
37]. Additionally, high-standard farmland construction may impact local ecosystems, such as altering original biodiversity [
38] and hydrological cycles [
39]. Moreover, excessive agricultural water conservancy may lead to groundwater level decline [
40] and soil salinization [
41]. Therefore, although HSFC is widely regarded theoretically and policy-wise as an effective approach to reducing agricultural carbon emissions [
42], comprehensive consideration of multiple factors is required during specific implementation, necessitating the adoption of scientifically sound planning and management measures to ensure its environmental benefits [
43] and sustainability [
44].
To address this gap, we have extended the existing research in various dimensions. Firstly, we conducted a comprehensive review of the policy landscape surrounding the establishment of the High-Standard Farmland Construction (HSFC) in China. This examination delineated the multifaceted reforms embedded within the policy framework, encompassing fields, soil, water, and infrastructure, aimed at mitigating challenges such as land fragmentation, deteriorating soil quality, and insufficient water resources, all of which serve as impediments to augmenting grain production capacity. Concurrently, the development of high-standard farmland expands the scope of agricultural land management, thereby fostering conducive conditions for the modernization of agricultural mechanization and the expansion of market capacity for outsourced social services. Secondly, we delved into the theoretical underpinnings concerning the nexus between the construction of high-standard farmland and Carbon Emissions from Agricultural Land Use(CEALU). Further exploration of basic farmland construction may engender practices conducive to land preservation and sustainable utilization, thereby elucidating the rationale behind curtailing carbon emissions from agricultural land, and thereby advancing initiatives for carbon emission reduction within agricultural land utilization. In this study, we employed a difference-in-difference (DID) model leveraging provincial panel data from China spanning the period 2005-2017. This model was instrumental in quantitatively evaluating the impact and regional disparities of HSFC policy on CEALU, thereby furnishing empirically-grounded and judicious policy insights for fostering future endeavors aimed at reducing CEALU through reliance on HSFC.
Figure 1.
The evolution of High-Standard Farmland Construction policies.
Figure 1.
The evolution of High-Standard Farmland Construction policies.
Figure 2.
Theoretical framework of the effect of HSFC on CEALU.
Figure 2.
Theoretical framework of the effect of HSFC on CEALU.
Figure 3.
Study area and Three geographical regions. Note: ①Eastern region: Beijing, Tianjin, Hebei,Lioaning, Shandong, Jiangsu, Zhejiang, Shanghai, Fujian, Guangdong, Hainan. ②Central region: Heilongjiang, Jilin, Neimenggu, Shanxi, Henan, Anhui, Hubei, Hunan, Jiangxi. ③Western region: Xinjiang, Xizang, Qinghai, Gansu, Ningxia, Shannxi, Sichuan, Chongqing, Guizhou, Yunnan, Guangxi. ④The base maps of research are made according to the Chinese standard map No. GS(2022)1873
Figure 3.
Study area and Three geographical regions. Note: ①Eastern region: Beijing, Tianjin, Hebei,Lioaning, Shandong, Jiangsu, Zhejiang, Shanghai, Fujian, Guangdong, Hainan. ②Central region: Heilongjiang, Jilin, Neimenggu, Shanxi, Henan, Anhui, Hubei, Hunan, Jiangxi. ③Western region: Xinjiang, Xizang, Qinghai, Gansu, Ningxia, Shannxi, Sichuan, Chongqing, Guizhou, Yunnan, Guangxi. ④The base maps of research are made according to the Chinese standard map No. GS(2022)1873
Figure 4.
Changes of CEALU per unit area during 2005–2017.
Figure 4.
Changes of CEALU per unit area during 2005–2017.
Figure 5.
Parallel trend test of differential model. Note: ① The vertical line passing through the origin is the 95% confidence interval of the corresponding estimated parameter. ② The abscissa axis represents the year of policy implementation. For example, -1 indicates the first year before policy implementation, 1 indicates the first year after policy implementation, and 0 indicates the starting year of policy implementation (i.e., 2011).
Figure 5.
Parallel trend test of differential model. Note: ① The vertical line passing through the origin is the 95% confidence interval of the corresponding estimated parameter. ② The abscissa axis represents the year of policy implementation. For example, -1 indicates the first year before policy implementation, 1 indicates the first year after policy implementation, and 0 indicates the starting year of policy implementation (i.e., 2011).
Table 1.
The main measures, content and purpose of HSFC policies.
Table 1.
The main measures, content and purpose of HSFC policies.
Standards |
Contents |
Zoning |
Objectives |
Safeguard Measures |
GB/T 33130-2016 |
Farmland Consolidation |
Northeast Region |
1.075 billion Mu (2025) |
Government Overall Planning |
GB/T33469-2016 |
Soil Improvement |
Huang-Huai-Hai Area |
1.2 billion Mu (2030) |
Planning Guidance |
GB/T 21010-2017 |
Irrigation And Drainage |
The Middle and Lower Reaches of The Yangtze River |
|
Fund Guarantee |
GB 50288-2018 |
Field Road |
Southeast Region |
|
Scientific and Technological Support |
GB 5084-2021 |
Agricultural Field Protection Ecological and Environmental Protection |
Southwest Region |
|
Supervision and Assessment |
GB/ T 30600-2022 |
Farmland Power Transmission and Distribution |
Northwest Region |
|
|
...... |
Science and Technology Service |
Qinghai-Tibet Region |
|
|
|
Management, Protection and Utilization |
|
|
|
Table 2.
The main measures, content and purpose of HSFC policies.
Table 2.
The main measures, content and purpose of HSFC policies.
Measures |
Content |
Purpose |
Agricultural measures |
Farmland Consolidation |
Optimize the spatial distribution of high-standard farmland |
Soil Improvement |
Improve the quality of cultivated land |
Forestry measures |
Protection forest of agriculture and forestry system |
Improve soil and water conservation and flood control |
Water conservancy measure |
Irrigation project |
Improve the guarantee rate of agricultural irrigation |
Drainage works |
Improve the ability to withstand storms |
Infrastructure construction measures |
Field road construction |
Improve the direct access road network to farmland |
Farmland electricity transmission and distribution |
Improve the quality and safety of electricity use |
Scientific and technological measures |
Location monitoring of cultivated land quality |
Tracking and monitoring the change of farmland quality |
Digital farmland construction |
Improve the level of precision and wisdom |
Table 3.
Carbon sources and coefficients of CEALU.
Table 3.
Carbon sources and coefficients of CEALU.
Carbon Sources |
Emission Coefficient |
Unit |
References |
Chemical fertilizer |
0.8956 |
Kg C /kg |
West and Marland [84] |
Pesticide |
4.9341 |
Kg C /kg |
Lu et al [85] |
Thin film |
5.180 |
Kg C /kg |
Tian et al [86] |
Total power of agricultural machinery |
0.18 |
kg C/kW |
Kuang et al [82] |
Tillage over |
312.6 |
kg C/ha |
Han et al [87] |
Irrigation |
25 |
kg C/ha |
Dubey et al [88] |
Table 4.
Descriptive statistics.
Table 4.
Descriptive statistics.
Variable names, symbols, and meanings |
Average value |
Standard deviation |
Min. |
Max. |
CEALU per unit area (C) , kg/ha |
482.22 |
182.04 |
170.16 |
1154.36 |
Proportion of land consolidation area (Hrate) , % |
0.05 |
0.09 |
0.00 |
0.97 |
Urbanization leve l(Urban) , Urban population as a percentage of total population , % |
0.52 |
0.14 |
0.20 |
0.89 |
Soil quality (Soil) , Soil erosion control area , kha |
3490.75 |
2847.04 |
0.00 |
13600 |
Field irrigation condition (Irri) , Effective irrigation area , kha |
1991.36 |
1537.66 |
115.50 |
6031.00 |
Per unit area yield of grain (Fyield) , Grain output per unit area , kg/ha |
5149.15 |
996.90 |
3045.73 |
7885.95 |
Investment level (Ginves) , Investment in fixed assets of the whole society , 100 million yuan |
374.11 |
418.17 |
3045.73 |
2675.94 |
The proportion of food crops (Frate) , Proportion of grain sown area to total sown area , % |
65.36 |
12.46 |
3045.73 |
2675.94 |
Labor input (Labor) , Headcount in primary industry , 10 thousand people |
938.83 |
694.87 |
37.09 |
3139.00 |
Economic development level (GDP) , PGDP , yuan |
28300 |
17800 |
5200.80 |
107000 |
industrial structure (Grate) , Proportion of agricultural output value to GDP , % |
10.99 |
5.63 |
0.36 |
32.73 |
Table 5.
The CEALU of each province in China in main years (kg/ha).
Table 5.
The CEALU of each province in China in main years (kg/ha).
Area |
2005 |
2008 |
2011 |
2014 |
2017 |
Mean |
Area |
2005 |
2008 |
2011 |
2014 |
2017 |
Mean |
Beijing |
692.91 |
689.35 |
721.74 |
931.61 |
1154.36 |
819.42 |
Hubei |
476.93 |
549.49 |
536.44 |
518.28 |
481.99 |
520.93 |
Tianjin |
613.26 |
717.79 |
669.49 |
627.22 |
544.22 |
660.25 |
Hunan |
356.47 |
399.14 |
387.07 |
385.34 |
399.75 |
390.27 |
Hebei |
438.18 |
456.72 |
471.19 |
493.86 |
487.03 |
471.80 |
Guangdong |
518.95 |
629.81 |
660.01 |
652.18 |
749.90 |
648.97 |
Shanxi |
313.68 |
343.16 |
377.01 |
403.82 |
406.91 |
374.96 |
Guangxi |
346.64 |
441.30 |
459.70 |
500.09 |
508.27 |
459.05 |
Neimenggu |
228.03 |
266.28 |
298.74 |
369.06 |
319.80 |
300.91 |
Hainan |
619.51 |
836.73 |
916.64 |
925.86 |
1097.88 |
889.25 |
Liaoning |
481.58 |
547.38 |
572.56 |
592.53 |
548.95 |
555.46 |
Chongqing |
282.97 |
336.16 |
348.73 |
344.49 |
361.51 |
338.94 |
Ji Lin. |
333.86 |
397.49 |
447.04 |
478.55 |
449.14 |
427.71 |
Sichuan |
297.99 |
329.08 |
343.88 |
342.65 |
337.41 |
334.26 |
Heilongjiang |
195.77 |
197.50 |
243.45 |
270.30 |
222.17 |
228.78 |
Guizhou |
193.13 |
237.16 |
233.98 |
230.81 |
218.67 |
226.15 |
Shanghai |
753.55 |
735.05 |
626.80 |
616.84 |
646.23 |
661.50 |
Yunnan |
303.82 |
357.00 |
385.79 |
411.49 |
450.27 |
383.14 |
Jiangsu |
531.30 |
543.64 |
538.28 |
526.27 |
504.84 |
532.59 |
Xizang. |
214.26 |
240.32 |
251.63 |
276.11 |
285.40 |
257.25 |
Zhejiang |
510.28 |
594.30 |
605.45 |
650.67 |
689.49 |
620.92 |
Shaanxi |
366.24 |
415.65 |
517.35 |
560.34 |
595.61 |
501.90 |
Anhui |
387.17 |
423.06 |
455.02 |
476.86 |
458.54 |
444.99 |
Gansu |
330.68 |
368.44 |
467.26 |
529.08 |
520.77 |
450.96 |
Fujian |
640.41 |
765.42 |
745.20 |
750.24 |
1068.85 |
796.57 |
Qinghai |
179.90 |
187.43 |
220.85 |
252.42 |
249.41 |
217.37 |
Jiangxi |
348.29 |
366.13 |
377.39 |
375.88 |
353.27 |
367.57 |
Ningxia |
293.47 |
320.92 |
358.32 |
371.31 |
418.07 |
355.78 |
Shandong |
637.42 |
646.54 |
633.58 |
609.28 |
567.59 |
627.25 |
Xinjiang |
464.76 |
536.15 |
562.74 |
684.53 |
651.85 |
571.09 |
Henan |
423.73 |
483.46 |
536.28 |
556.52 |
538.64 |
513.04 |
Tatal |
392.58 |
433.03 |
456.09 |
473.32 |
457.72 |
447.45 |
Table 6.
The results of regression model estimation.
Table 6.
The results of regression model estimation.
Variables |
Fixed effect-based |
Random effect-based |
Standard error based on POLS |
|
-0.1080** (0.0499) |
-0.1080** (0.0520) |
-0.1080** (0.0520) |
|
-0.4620 (0.4899) |
-0.4620 (0.5104) |
-0.4620 (0.5104) |
|
0.3540** (0.1346) |
0.3540** (0.1402) |
0.3540** (0.1402) |
|
-0.5375** (0.2098) |
-0.5375** (0.2186) |
-0.5375** (0.2186) |
|
0.2671** (0.1142) |
0.2671** (0.1190) |
0.2671** (0.1190) |
|
-6.27E-12 (2.20 E-11) |
-6.27 E-12 (2.30 E-11) |
-6.27 E-12 (2.30 E-11) |
|
-0.1373 (0.0937) |
0.0101 (0.0204) |
0.0101 (0.0204) |
|
0.0195 (0.0267) |
-0.1373 (0.0976) |
-0.1373 (0.0976) |
|
0.0195 (0.0267) |
0.0195 (0.0278) |
0.0195 (0.0278) |
|
0.0025 (0.0063) |
0.0025 (0.0066) |
0.0025 (0.0066) |
Constant term |
4.4349** (1.8696) |
5.6299*** (1.8341) |
5.6299*** (1.8341) |
Sample size |
390 |
390 |
390 |
|
0.6349 |
— |
0.9701 |
Table 7.
The estimation of the dynamic impact of HSFC policies on CEALU.
Table 7.
The estimation of the dynamic impact of HSFC policies on CEALU.
Variable |
Parallel trend FE |
Parallel trend RE |
Parallel trend RE |
Parallel trend FE |
Parallel trend RE |
|
-0.2367 (0.4503) |
-0.1323 (0.4654) |
|
-1.5235** (0.6830) |
-1.4123** (0.7018) |
|
-0.2207 (0.4516) |
0.0391 (0.4639) |
|
-1.2614 (0.8493) |
-1.1504 (0.8668) |
|
-0.1524 (0.4578) |
0.0219 (0.4711) |
|
-2.5768*** (0.9405) |
-2.4910*** (0.9524) |
|
-0.4758 (0.4689) |
-0.3641 (0.4834) |
Constant term |
2.2557*** (0.6967) |
2.7613*** (0.6618) |
|
-0.9722** (0.4578) |
-0.8870* (0.4721) |
Control variable |
Controls |
Controls |
|
-0.0857 (0.0535) |
-0.0766 (0.0552) |
Observed value |
390 |
390 |
|
-0.0872 (0.0673) |
-0.0716 (0.0692) |
F |
28.2418 |
— |
|
0.5567 |
— |
Table 8.
The robustness test of changing the time of policy intervention.
Table 8.
The robustness test of changing the time of policy intervention.
Variable |
Take 2008 as the policy implementation point |
Take 2009 as the policy implementation point
|
(1) Fixed effect |
(2) Random effect |
(3) Mixed effect |
(1) Fixed effect |
(2) Random effect |
(3) Mixed effect |
|
-0.7225 (0.5729) |
-0.5015 (0.5891) |
-0.7225 (0.6315) |
|
|
|
|
|
|
|
-0.5749 (0.4945) |
-0.4214 (0.5042) |
-0.5749 (0.5450) |
Constant term |
3.5272** (1.4690) |
3.9660*** (0.8695) |
4.5418*** (1.5904) |
3.4980** (1.5129) |
4.0173*** (0.8893) |
4.5250*** (1.6316) |
Control variable |
Controls |
Controls |
Controls |
Controls |
Controls |
Controls |
Sample size |
180 |
180 |
180 |
180 |
180 |
180 |
|
0.7062 |
— |
0.9901 |
|
|
|
Table 9.
The results of heterogeneity analysis.
Table 9.
The results of heterogeneity analysis.
Variable |
Eastern region |
Central region |
Western region |
|
-0.0262 (0.0727) |
-0.3667** (0.1806) |
0.0364 (0.1527) |
Constant term |
14.0595*** (1.8904) |
0.1450 (1.7205) |
3.0510*** (0.9514) |
Control variable |
Controls |
Controls |
Controls |
Sample size |
130 |
104 |
156 |
|
0.6430 |
0.7796 |
0.8121 |