1. Introduction
Cultivated land is the basic resource and condition for human survival. However, the extensive use of chemical fertilizers has seriously threatened the quality and safety of cultivated land in recent years. China is not only the world’s largest fertilizer producer and consumer but also ranks among the top in terms of fertilizer-use intensity around the world. According to the statistics of the Food and Agriculture Organization of the United Nations, in 2019, China’s agricultural chemical-fertilizer-application amount was 47.55 million tons, and the agricultural chemical-fertilizer application per unit area was 350.50 kg/ha, far exceeding the internationally recognized safe upper limit of 225 kg/ha for chemical fertilizer application [
1]; it was the main source of agricultural non-point-source pollution. At the same time, the current effective utilization rates of nitrogen, phosphate and potash fertilizers in China were only 33%, 24% and 42%, respectively [
2]. The long-term excessive input and inefficient use of chemical fertilizers will not only destroy the soil structure, lead to soil hardening and acidification, nutrient imbalance, the deterioration of biological characteristics, increase the cost of agricultural production and hinder the sustainable development of agriculture [
3] but also pollute the air and water sources, reduce the yield and quality of crops and ultimately endanger human health [
4,
5]. Therefore, the Chinese government attached great importance to the problem of agricultural non-point-source pollution and actively promoted the reduction of chemical fertilizers and soil-pollution control. In 2015, the Ministry of Agriculture and Rural Affairs issued the “Action Plan for Zero Growth of Fertilizer Use by 2020”. In 2022, the State Council issued the “14th Five-Year Plan for Promoting Agricultural and Rural Modernization”, which clearly proposed to effectively curb agricultural non-point-source pollution and ensure a continuous reduction in the use of chemical fertilizers by 2025.
Farmers are the microsubjects of China’s agricultural production, and the amount of fertilization is the result of farmers’ individual rational decisions. The reduction of chemical fertilizer application and the realization of agricultural sustainable development goals depend on the transformation of farmers’ production behavior. Therefore, we first need to understand what factors influence the intensity of fertilizer application by smallholder farmers. The existing research on the influencing factors of farmers’ chemical-fertilizer-application behavior can be summarized into the following three aspects: first, farmers’ individual and family characteristics, such as age, gender, family size, education level, attitude perception, risk preference, non-agricultural employment, etc. [
6,
7,
8]; second, the characteristics of production and operation, such as planting structure, the proportion of the family farming labor force, whether employees are employed in agricultural operations, whether information technology is used, the degree of commercialization of agricultural products, etc. [
9,
10,
11,
12]; third, the external environment, such as technical training, the stability of land-property rights, agricultural subsidy policy, etc. [
13,
14,
15].
Land is the most important input factor in agricultural production. Land management characteristics such as the scale of land management, the degree of land fragmentation and land rent had an important impact on the fertilizer application behavior of farmers [
16,
17,
18]. Among them, the logic of realizing fertilizer reduction by expanding the scale of cultivated land management has received widespread attention from the academic community. Existing studies have pointed out that farmers’ production investment decisions mainly consider cost and benefit, and the small scale of land management may lead to insufficient incentives for long-term investment income [
19], and improving economies of scale through increasing land can effectively motivate farmers to make long-term production investment and adopt chemical-fertilizer-reduction technology [
20]. Some scholars confirmed the effect of fertilizer reduction on the scale of cultivated land management at the empirical level. For example, Liang et al. [
21] used the data on 1314 rice farmers in the main rice production area of Hubei Province, China, and found that the management scale of rice has a significant negative impact on the amount of fertilizer applied; Ju et al. [
22] analyzed the relationship between land management scale and farmers’ fertilizer input using data from the National Bureau of Statistics of China and also found that, with the expansion of the scale of farmers’ management, the amount of fertilizer input decreased rapidly; Wu et al. [
23] used the panel data of 74 countries from the 1960s to the early 2000s found that one standard deviation (SD) increase in farm size reduced fertilizer use by 102% of its SD. However, some studies also believed that with the expansion of the management scale, the problem of the excessive application of chemical fertilizers by farmers had not been effectively alleviated and had even aggravated the short-term chemical-fertilizer-application behavior of farmers [
24]. It can be seen that the academic community has not yet reached a consensus on whether the large-scale management of cultivated land can promote the reduction of chemical fertilizers.
Can expanding the scale of cultivated land management reduce the intensity of fertilizer application by farmers? If it can, what is the specific mechanism of action? This article used the 2019 China Rural Household Panel Survey database of Zhejiang University to conduct research on the above problems, in order to provide ideas for solving the problem of excessive fertilizer input and promoting green agricultural production.
This research contributes to cultivated land management and fertilizer reduction in the following ways. Firstly, we empirically studied the impact of the scale of cultivated land management on fertilizer reduction based on the national representative farmer-household data. Although some studies have used the microdata of a specific region of China to study this problem, whether the research conclusion is suitable for China as a whole remains to be discussed. Our sample well covered the three regions of China’s east, middle and west, and the research conclusions obtained were more universal. Secondly, we introduced the dummy variables of crop type into the econometric model to control the differences in the amount of fertilizer per unit area of different crops, so that the obtained estimation results were more accurate. Many studies did not distinguish the types of crops in detail. Thirdly, we deeply discussed the impact mechanism of the expansion of the scale of cultivated land management on fertilizer reduction and used large-scale microdata to empirically test the impact path. In fact, the discussion of relevant mechanisms in the existing studies was limited to theoretical reasoning and lacked rigorous empirical analysis.
5. Discussion
In this study, the large-scale survey data of 5031 farmers were selected to study the effect of the scale of cultivated land management on fertilizer reduction from the perspective of cultivated-land-management characteristics. This study not only studied the effect of the scale of cultivated land management on farmers’ chemical-fertilizer-application behavior but also empirically examined the impact mechanism of the expansion of the scale of cultivated land management on fertilizer reduction, which is comprehensive and practical. In addition, this study also discussed the impact of farmland fragmentation on fertilizer reduction. As the largest developing country in the world, the research results of China’s rural areas have strong practical significance. This article can provide reference for other developing countries to promote chemical fertilizer reduction and realize the sustainable use of cultivated land.
Through empirical research, we found that the larger the scale of cultivated land management, the lower the application of chemical fertilizer per hectare. This finding corresponds to studies done by Foster and Rosenzweig [
37] and Akpan et al. [
38]. Foster and Rosenzweig [
37] argued that the application of fertilizer decreased with the expansion of the scale of land in India. Based on the data of 150 farmers in southern Nigeria, Akpan et al. [
38] found that a unit increase in the farm size will reduce the possibility of adopting fertilizers by 13.23%. The main reason for these results is that small farmers are less organized, the adoption of new technologies has high learning costs and the lack of effective channels to transfer knowledge to farmers [
23], resulting in low agricultural production efficiency, the unreasonable input of factors and the excessive input of chemical fertilizers [
22]. However, the findings of this study are different from those of Bambio and Agha [
24]. They believed that scale operation is not conducive to reducing the use of chemical fertilizers. The purpose of large-scale operation is to maximize profits, which increases the motivation for chemical-fertilizer investment. For the transferred land, the overall non-point-source pollution level is higher due to the changes in planting methods and planting objects. In addition, the fragmentation of cultivated land is not conducive to fertilizer reduction, which is consistent with the research of Gao et al. [
39], who believed that the high degree of fragmentation is an important reason that the fertilizer-application rate of Chinese farmers is higher than the world average.
In terms of other factors, men used more chemical fertilizers than women. It is generally believed that, in the process of chemical fertilizer application, the differences in the psychological characteristics of men and women make women pay more attention to their own safety and health, so women tend to use less chemical fertilizers, which is consistent with the findings of Yuan et al. [
40]. Thus, an increase in total household income will hinder the reduction of fertilizer, and the possible explanation is that households with higher income are more willing to increase agricultural productivity by increasing fertilizer input [
41]. Additionally, the higher the proportion of family farming labor, the greater the intensity of fertilizer application by farmers. This is because agricultural operation income is the main source of income for such families, and the goal of agricultural production is to maximize profits and minimize risks. In order to ensure grain production, more fertilizers are used [
42]. Finally, farmers who employ workers tend to reduce the amount of fertilizer used. A possible reason is that farmers who do not employ workers have to use more chemical fertilizers to make up for the lack of labor and ensure a certain amount of grain output [
43], while farmers employing workers is equivalent to increasing labor input to replace fertilizers.
There are also some shortcomings in this study, which can be made up in future research. Specifically: (1) We selected the cross-sectional data of CRHPS in 2019 as the research sample of this study. However, the impact of the expansion of cultivated land management on fertilizer reduction is dynamic. Therefore, future studies can use panel data to further extend and verify the relationship between the two. (2) Based on a representative sample of rural households in China, this article studied the relationship between the scale of cultivated land management and fertilizer reduction. Whether this relationship is applicable to other developing countries remains to be explored.
6. Conclusions
This article first theoretically analyzed the effect of the scale of cultivated land management on farmers’ fertilizer-application amount and its mechanism and then used the nationally representative rural household survey data from 2019 to empirically test the influence and mechanism of the scale of land management on farmers’ fertilizer-application intensity by applying the OLS model. The main conclusions are: (1) The expansion of the land management scale promoted a reduction in the use of chemical fertilizers. Specifically, for every 1 ha increase in the average grain sown area per household, the amount of fertilizer applied per hectare decreased by 20.6%. (2) The individual household head and the characteristics of the family also significantly affected the fertilizer-application intensity of farmers. Among them, gender, total household income and the proportion of agricultural labor led to an increase in fertilizer application by farmers, while employing workers in agricultural production and operation had a significant negative impact on farmers’ fertilizer use. (3) The expansion of the scale of cultivated land management can reduce the amount of chemical fertilizers by encouraging farmers to adopt agricultural technology and mechanized fertilization. (4) The degree of cultivated land fragmentation increased the amount of fertilizer applied per hectare.
Based on the above research conclusions, the policy implications are as follows: (1) The government should guide farmers to develop appropriate-scale operations based on factors such as farmers’ management capabilities and regional resource endowments. At the same time, on the basis of the expansion of the scale of land management, localities should promote the concentration of land plots through various measures, so as to provide favorable conditions for farmers to reduce their input of chemical fertilizers. (2) Actively publicizing and promoting green agricultural technologies such as fertilizer reduction is important, as is giving play to the important role of socialized service organizations in agricultural technology promotion and farmer education. For training services with large positive externalities, relevant government departments should give certain financial subsidies. (3) Guiding the specialized development of regional planting structure, encouraging farmers to carry out a horizontal division of labor and contiguous planting, creating conditions for paying attention to the advantages of an at-scale economy of agricultural mechanization and releasing their potential for fertilizer reduction would all be helpful policies. (4) Additional benefits could come from improving the scale of the cultivated land management for farmers through land transfer, especially by encouraging contiguous transfer and land-replacement integration to reduce the degree of land fragmentation.