Food is an important basis for national development, and food security is related to the harmony and stability of society [1
]. Maize production is fundamental for the global food system and has great potential for yield increase, and is currently widely grown worldwide. It has become an indispensable source of food, feed, and industrial raw materials [2
]. Therefore, the sustainable production of maize is of great significance to ensure national and global food security, and for the effective supply of agricultural products.
Maize, of all food crops, has the greatest potential for production increase, and the growth in demand has become irreversible in China [3
]. In 2020, China’s maize-sown area was 41.26 million hectares, with an output of 261 million tons, accounting for 38.94% of China’s grain yield, ranking second in the world [4
]. Maize in China is mainly cultivated in the northeast, north, southwest, and northwest, roughly forming a long oblique planting belt from northeast to southwest. Northeast and North China contribute 70% of the country’s maize production (Figure 1
]. However, China’s maize development is inefficient and still struggles with duplication of efforts, especially in smallholder agriculture [6
]. This is closely related to China’s long-term output-oriented food policy, including the excessive application of fertilizers and pesticides [7
]. Such extensive production and management methods endanger sustainable agriculture and rural development in China. These challenges in China’s maize production remind policymakers to balance production and productivity, which necessitates an in-depth analysis of how to improve the efficiency of maize production.
Drought is the main constraint factor for crop production in rain-fed systems around the world [8
]. However, global freshwater supplies are facing unprecedented challenges and risks [9
], which seem to be more serious in China because of China’s uneven distribution of water and its water pollution crisis. Meanwhile, agricultural irrigation is the largest water-use sector, accounting for about 70% of global water withdrawals and nearly 90% of consumptive water use [10
]. Existing studies have provided evidence on the close relationship between water use and maize production. For example, Cao et al. explored spatiotemporal patterns of water use efficiency and found it played an important role in maize production [11
]. Zheng et al. found that water productivity on a regional scale is useful for identifying and managing inefficiencies in crop production systems [12
]. The North China Plain is one of the most seriously over-exploited groundwater areas, with a 13.92 million km² land area of a distributed groundwater-level drawdown funnel group, and a funnel area of more than 9700 km2
]. In our research area, Hengshui city, the groundwater has been used as a water source for drinking water and for intensive agriculture activities for many years, which has resulted in the over-exploitation of typical groundwater in the Hengshui area.
A line of literature, most related to our work, studies a certain set of factors affecting agricultural productivity. The theoretical and empirical literature acknowledge that determinants of agricultural productivity can be categorized into three types: crop production management (e.g., irrigation), socioeconomic factors (e.g., farmers’ education level), and climatic factors (e.g., precipitation). In terms of crop production management, the most direct impact on maize production is inseparable from the various field management methods such as breeding, fertilization, weeding, and irrigation, and the focus should be on the effects of these management factors on crop yield [15
]. In terms of socioeconomic factors, previous studies have found that the education level of the farmers is positively related to agricultural productivity [19
]. The underlying reason is that education enhances the farming skills and productive capabilities of the farmers and enables them to follow written instructions regarding the application of adequate and recommended doses of chemicals and other inputs [20
]. In another study, Guo et al. found that elderly farmers, who do not intend to abandon farming, had higher agricultural outputs compared to other farmers, suggesting that a farmer’s age may also have a positive effect on agricultural productivity [21
]. On the other hand, agricultural productivity may be reduced as a result of aging farmers’ physical deficiencies. In terms of climatic factors, empirical studies have found that agricultural productivity is significantly affected by certain climate variables, including precipitation, humidity, and temperature [22
]. Under unfavorable climatic conditions, such as water deficits and temperature extremes, the reproductive phase of plant growth will be influenced, and in cereals, flower initiation and inflorescence are negatively affected by water stress [23
Furthermore, this paper is closely related to other studies on different measurements of grain productivity. In general, the most used tools for analyzing agricultural production efficiency include data envelopment analysis (DEA) and SFA, which are frequently used on a global level across different issues [24
]. The SFA is a parametric technique involving the estimation of a specific parameterized efficient frontier with a composite error term, while the DEA is a non-parametric linear programming methodology that quantifies the relative efficiency of multiple similar entities or decision-making units (DMUs) [28
]. One major drawback of the DEA is that derived TFP often draws inconsistent conclusions, partly because it cannot distinguish productivity from measurement errors and white noise [29
]. The SFA allows for the separation of inefficiency from random shocks or measurement errors [32
], thus presenting an advantage over other parametric and non-parametric methods [33
]. With these advantages, the SFA has gained popularity for measuring agricultural productivity.
Although existing studies have provided theoretical foundations and empirical findings on agricultural productivity and its influencing factors, most of them measured the efficiency at the intranational or interprovincial scale [34
]. However, agriculture is a remarkably diverse industry that is greatly affected by differences in farmers’ attributes and field environments [35
]. These studies are mainly macro-level analyses using aggregated data, which cannot reflect the circumstances of individual villages and farmers, and the implications obtained tend to be vague. To relieve the estimated bias resulting from such regional heterogeneity, especially the uneven distribution of water resources, more research is needed on the grain production efficiency at the county level. The significance of this research is that it can lead to concrete policy recommendations by analyzing from a micro-level perspective based on in-depth interviews with farmers. The study area itself is another point of significance in this study: Hengshui, of Heibei province, is the largest overdraft area and is an important region for maize production in the North China Plain. The findings of this study are expected to clarify ways in which the efficiency of maize production in North China or in other arid and semi-arid regions around the world, can be improved.
Given the above background, the objectives of this study are twofold. (i) The first is to use the SFA to estimate the efficiency of maize production in Hengshui based on the cost-benefit analysis. To investigate the potential nonlinear relationship between the maize output and certain inputs, the quadratic term of irrigation costs and chemical fertilizer use were incorporated into the stochastic frontier production function, which followed the form of the Cobb–Douglas function. (ii) The second objective is to identify the key determinants triggering inefficiency in maize productivity. The influencing factors of maize inefficiency mainly included temperature, precipitation, humidity, average years of school attainment of farmers, and the farmers’ age. This analysis could shed new light on improving the efficiency of maize production from the perspective of socioeconomic and climatic indicators.
4. Conclusions and Policy Implications
Maize has the greatest potential for production increase and the amplest room for growing consumer demand in China. However, China’s maize development still struggles with high costs, poor benefits, and farmers’ low enthusiasm for production. Based on the cross-sectional data of field investigation in the Hengshui area of the North China Plain, this study performed a detailed descriptive statistical analysis of the costs and benefits of the whole maize production process. A stochastic frontier model was then used to empirically analyze productivity and the factors related to the inefficiency of maize production.
Our findings from the cost-profit analysis suggest that in the process of maize planting, the modes of fertilization, pesticide application, and irrigation are still relatively extensive. This not only leads to the redundancy of production inputs to some extent but also results in the waste of water resources and non-point source pollution. The results of the stochastic frontier model show that there is an inverted U-shaped relationship between irrigation cost and maize output. Specifically, when the irrigation cost is about 938 yuan·ha−1, the maize output per unit area is optimal. The estimated inflection point is within the optimal range of Agricultural Irrigation Water Quota and Agricultural Water Quota Standard of Hebei Province, suggesting the validity of our results. In addition, there is also an inverted U-shaped relationship between fertilizer cost and maize output. When the fertilizer cost is 2547 yuan·ha−1, the loss of technical efficiency of maize output is minimal. The results of the inefficiency influencing factor model show that temperature and humidity are all positively associated with the non-efficiency of maize production.
The above research findings have important policy implications for the national maize production: first, farmers or cooperatives should monitor and calculate the cost of the whole process of maize production to avoid redundant inputs in the production process. Second, the government should upgrade the agricultural socialized service system to help farmers adopt new agriculture technology in modern farming. Policymakers should also provide professional guidance for fertilization and pesticide application, aiming to avoid excessive use of fertilizers and pesticides, and improve the efficiency of fertilizer and pesticide use. Third, innovating agricultural irrigation methods and promoting water-saving irrigation technology are effective measures for reducing irrigation costs. At the same time, technologies such as dry-land surface mulching, returning straw to the field, and subsoiling should be further developed to improve water use efficiency. Furthermore, the government, research institutions, and farmers should strengthen their cooperation to promote the sustainable development of China’s maize production.