1. Introduction
A vast population and limited farmland are fundamental realities in China [
1]. With rapid economic development and improvements in the standard of living, the structure of family food consumption is continuously being upgraded and optimized, which drives the consumption of grains [
2]. However, due to constraints on natural resources, such as water and soil, grain production in China is close to reaching its “ceiling” [
3]. Hence, with the consistent growth in food demand, China’s food security is facing challenges [
4].
Food security can be ensured in two ways: by increasing production and by reducing postharvest losses and waste [
5]. Under the conditions of limited land and water resources, continued growth in food production for China is unrealistic. Thus, reducing postharvest losses and waste must play an important role in ensuring food security [
6].
Due to technical limitations, insufficient social awareness and other reasons, such as income increases, food losses and waste, are more serious in China than in developed countries [
7]. The postharvest loss rate of China’s staple food is 7.9%, which is approximately twice the average level of developed countries [
8]. These losses also reflect the meaningless consumption of input resources. Hence, reducing postharvest losses and waste can increase the domestic food supply, save agricultural production factors, and improve the ecological environment.
The food system includes several stages, such as harvesting, storage, transportation, and consumption [
9]. Harvesting is an important stage, and losses at this stage are directly related to grain outputs [
10]. Most of the literature on grain harvest losses has focused on South Asia and Sub-Saharan Africa. Maize farmers in eastern Tanzania reported that 11.7% of their harvest was lost in the system, and approximately one-third of this loss occurred during harvesting [
11]. Harvest losses in South Asia seem to be lower than those in Africa, and the harvesting loss rates of rice (including harvesting, threshing, grain cleaning, and transportation) in India and Bangladesh are 1.62% and 1.75%, respectively [
12,
13].
Harvest losses in China are different from losses in Africa and South Asia. Researchers found that most farmers who were interviewed believed that rice harvest losses were 4% or lower in China, although there were differences between regions [
10]. Liu et al. (2013) comprehensively reviewed the available information concerning food losses and waste in China. Their results reveal that the food loss rate (FLR) of grains in the entire supply chain was 19.0% ± 5.8% in China, and the harvest stage had the third largest FLR in the supply chain, with estimated losses of 3.5% (±2.6%) [
7].
Although substantial time and effort have been invested in these studies, differences in scope and research methods have led to large gaps in the research results. In particular, due to small sample sizes or small-scale surveys, studies on grain harvest losses in China only reflect the circumstances in certain areas. These studies have not yielded a sufficient understanding of the current situation in China. In addition, several analyses have been based on second-hand data, which are easily prone to statistical bias. Moreover, many studies have only examined the level of grain harvest losses; in-depth analyses of the determinants of harvest losses, according to which one might propose targeted reduction methods, have not been conducted.
Based on previous studies, compared with manual harvesting, mechanical harvesting is rough and can easily lead to crop damage and omissions; thus, farmers who use mechanical harvesting methods have higher harvest losses than those who harvest manually [
14,
15]. Poor work attitudes or labor shortages have also been shown to lead to higher losses; studies have also demonstrated that farmers who have received agricultural technology training have relatively low harvest losses [
16,
17]. Additionally, weather conditions during the harvest period are an important factor that affects harvest losses. Bad weather, such as strong winds and rainfall, increases harvest losses; moreover, bad weather conditions increase the moisture content of grains, which can easily lead to mildew and serious storage losses [
18].
Few studies have considered the impact of farm size on harvest losses. In China, more than 500 million people still live in rural areas, and family-based smallholder production continues to be the main way for Chinese farmers to make a living [
19]. To ensure fairness, land distribution under the household contract responsibility system adopts the principle of equality. Due to the large population, for each household, the land area is limited [
20], which prevents large-scale operations, decreases operating efficiency, increases management costs, and is not conducive to mechanization [
21].
With the continuous outflow of the rural population, the Chinese government has gradually introduced policies and laws that encourage land transfer, and the scale of certain farms has expanded [
22]. In 2018, the land transfer area exceeded 530 million mu (35.33 million ha), which means that more than 30% of arable land has been involved in land transfer
1. Through land transfer, land can be reallocated from low-efficiency farmers to high-efficiency farmers, thereby improving factor allocation and production efficiency and significantly affecting agricultural production and social and economic development [
23].
Numerous detailed analyses of the impacts of expanding the size of farms, especially the effects on grain production, have been conducted. However, these studies have failed to identify the relationship between farm size and harvest losses, and thus, the mechanism by which farm size affects harvest losses is unknown.
Based on survey data from 1526 rice growers in 21 provinces in China, we measured rice harvest losses and the implications for natural resources and the environment and then analyzed the relationship between farm size and rice harvest losses. Rice is one of the three major grains and an important staple food in China. In 2021, the rice output in China reached 212.84 million tons, and the rice sowing area reached 29.92 million hectares, accounting for 31% of China’s total grain output and 25% of the total grain sowing area
2. In 2020, China’s rice output was the highest in the world and accounted for 28% of global rice output
3.
Our results show that, on average, 98.69 kg of rice was lost for each household during the harvest stage, equal to 3.45% of the total harvest lost at this stage. These losses reflect a massive meaningless consumption of inputs. Based on our measurements, the total rice harvest loss was 7.31 million tons in China, which could meet the food needs of 16.26 million people for one year, resulting in the wasted use of 1.01 million ha of land and 95.17 billion m3 of water. Meanwhile, empirical results show that there is an inverse relationship between farm size and rice harvest losses, which means that expanding the size of farms can help reduce rice harvest losses. We found that large-scale farmers are more inclined to use agricultural machinery services during the harvest stage, which has been proven to decrease losses.
The results of this study supplement the findings in the literature and contribute to an accurate understanding of changes in harvest losses during the transformation period of China’s agriculture. Thus, this study is of substantial significance to national food security and food policies. The structure of the article is as follows: the second section presents the data collection process and descriptive statistics, the third section describes the methodology, the fourth section presents the results and the robustness test, and the fifth section provides the conclusion.
4. Conclusions
Based on survey data from 1526 households in 17 provinces in China, we evaluated rice harvest losses and then used a fractional logit model to analyze the impact of farm size on rice harvest losses. The results show that, on average, 98.69 kg of rice was lost for each household during the harvest stage, equal to 3.45% of the total harvest. The most serious rice harvest losses occurred in Northwest China, with 5.53% of the total harvest lost during the harvest stage. This result implies that rice harvest losses in economically developing and humid regions are more serious than those in economically developed and dry regions.
Harvest losses result in the meaningless consumption of inputs and have a substantial impact on the environment. Based on our measurements, the total rice harvest loss reached 7.32 million tons in China. This loss of rice, which could meet the food needs of 16.26 million people for one year, resulted in the waste of 1.01 million ha of land, 34.33 ten thousand tons of fertilizer, and 95.17 billion m3 of water, and increased carbon emissions by 2.71 million tons.
The study also found that mechanical harvesting results in higher losses than the manual harvest method. However, because of the large efficiency gap, farmers will inevitably continue to adopt mechanical methods as agriculture develops. Thus, the government will be required to introduce policies, such as providing subsidies, to encourage farmers to use more advanced machines to reduce such losses. Moreover, the empirical results reveal an inverse relationship between farm size and rice harvest loss rate, which seems to be a contradiction. In our perceptions, large-scale farmers often prefer mechanical harvesting, which will increase losses. However, our study found that large-scale farmers are more likely to adopt agricultural machinery services, and these professional harvesting teams can reduce losses. In China, providers of agricultural machinery services use more advanced machinery, and they regularly maintain and upgrade their machines. Furthermore, the government also provides training programs for machinery operators from agricultural machinery services companies, which makes them more skilled. These operators adapt their machinery operations to the specific conditions of the harvested plot and crop growth, which can reduce losses. When we replaced the key variables and re-estimated the model, the relevant conclusions remained valid, which indicates that expanding the size of farms can reduce rice harvest losses. As China’s rice harvest losses are higher than those in developed countries and regions, it may be necessary to encourage the use of more efficient agricultural machinery services for harvesting and to promote other harvesting practices used on large-scale farms to better protect national food security.
This study used representative agricultural information from China, a country undergoing agricultural transition, to confirm the impact of farm scale and agricultural machinery services on harvest losses. Our findings have important implications for improving world food policies, especially for countries in Africa and South Asia that are—similar to China—also in the stage of transformation development. Of course, other factors, such as region, labor, and variety, may also have a significant impact on harvest losses. However, it is not possible to cover all relevant factors in a single study. Hence, we urge future researchers to extend our discussion, such as by examining the impacts of varieties on harvest losses.