1. Introduction
Anaerobic digestion is increasingly used to generate biogas from livestock manure worldwide. It has been shown to create significant economic and environmental benefits [
1,
2,
3], especially in greenhouse gases emission reduction. Anthropogenic activities that directly or indirectly release methane into the atmosphere are responsible for as much as a third of the global warming occurring at the present time [
4]. Livestock farming is one of the leading anthropogenic sources of greenhouse gases emission. The feasibility of mass anaerobic digestion of livestock manure for biogas production has therefore attracted increasing attention among policymakers and researchers. Research has been performed on the cost-benefit analysis of biogas production from livestock manure from the standpoint of livestock farmers [
5,
6,
7,
8]. Whereas some studies find biogas production from livestock manure to be beneficial, others find opposite results. For example, Kiratikarnkul [
9] conducted a cost-benefit analysis of alternative manure disposal methods in the hog sector of Thailand and found that biogas production actually provides fewer benefits than some of the other disposal methods. Ribeiro et al. [
10] also came to a similar conclusion that energy production from poultry manure does not demonstrate economic viability. From the perspective of energy production, there are also some other alternative manure management techniques, including co-combustion and gasification [
11,
12], which have been shown to be feasible and promising. This also indirectly supports the feasibility of biogas production from livestock manure. Although there is no consensus in the literature, examples exist that livestock farmers around the world are installing anaerobic digesters to treat manure and produce biogas. It is thus important to understand what factors lead livestock farmers to install such biogas digesters.
With the increasing size of livestock farms, the volume of livestock manure also increases significantly with a steadily growing trend. According to FAO [
13], the global production of livestock manure (in terms of nitrogen content) increased from 73.9 million tons in 1961 to 127.6 million tons in 2019, with an average annual growth rate of 0.95%. Improper management of manure from farms can produce adverse environmental and health effects [
14,
15]. The increased concentration of livestock farms has further exacerbated the risk of environmental pollution and health damage [
16,
17,
18]. From the perspective of manure sources, beef cattle are the main source of livestock manure. In 2019, the global production of beef cattle manure was 46.3 million tons, accounting for 31.9% of total livestock manure [
13]. From a regional perspective, Asia produces the largest amount of livestock manure, accounting for 37.1% of the global manure production in 2019, most of which is from China. In 2019, China’s livestock manure reached 12.4 million tons, ranking first in the world [
13]. China is facing a significant challenge in sustainable manure management [
19,
20]. Therefore, using China as a case study to explore the management of livestock manure, especially beef cattle manure, is of great representativeness.
Biogas production from livestock manure through anaerobic digestion is one of the most effective greenhouse gas mitigation options for manure management [
21]. The evaluation of energy potential is also one of the manifestations of the feasibility of biogas production. Previous studies focus on a certain region (e.g., Turkey, Iran and China) or a certain animal species (e.g., poultry, hog, goat, and dairy cattle) to evaluate the biogas potential of livestock manure [
1,
22,
23,
24]. Ayhan et al. [
25] conduct laboratory-scale experiments to evaluate biogas production from the co-digestion of dairy cattle manure and maize silage and show that co-digestion has positive effects on biogas production and the methane content of biogas. Other studies comprehensively and systematically investigate the potential economic and environmental feasibility of biogas production from livestock manure. For example, Manesh et al. [
26] conduct a feasibility study on the energy, economic and environmental impacts of biogas production from poultry manure in Iran and find low use of Iran’s capacity for biogas production despite its high potential.
There are different ways to manage livestock manure. The common techniques include land application, processing it into organic fertilizer, processing it into substrate, and anaerobic digestion [
27]. Among these techniques, the land application of manure is the most widely used eco-friendly and traditional approach [
28,
29]; however, it is limited by the availability of cropland [
30,
31,
32], especially in recent years. At present, the rate of manure applied to cropland is only 21.3% in 2019 [
13]. With the separation of crop and livestock farming, the land application of manure is becoming more and more difficult, and disadvantages of this method are gradually being exposed in the form of risks of air and water contamination [
33,
34,
35]. On the other hand, anaerobic digestion is a clean and efficient way to treat livestock manure. It provides a renewable energy source that is clean and can easily replace firewood or fossil fuels [
26]. Thus, biogas production from livestock manure via anaerobic digesters (i.e., biogas digesters) is becoming popular around the world and is considered by governments for both sustainability and energy security purposes. Various measures have been introduced to promote the installation of biogas digesters, including training programs targeting livestock farmers. Whether such training programs motivate livestock farmers to install biogas digesters remains to be examined.
Training is a form of communication intended for the purpose of developing skills, modifying behavior, and increasing competence. It is generally targeted at a specific group and focuses on a specific topic. Training related to sustainable farming practices is generally provided directly by government agencies or third-party training vendors hired by the agencies. For example, in the U.S., agricultural extension centers provide various training to local farmers in the form of classes, workshops and field trips. In China, technical experts are often hired by the government to carry out training in classrooms [
36]. Therefore, training related to sustainable farming practices has a strong attribute of public goods.
There are three major types of agricultural training programs: policy-oriented training that focuses on providing policy information, technology-oriented training that focuses on providing technical guidance, and field-based training that focuses on the experiential learning experience. Policy-oriented training is a common type of training. This training can improve farmers’ awareness of policies related to sustainable farming practices, facilitate the timely and comprehensive understanding and familiarity with relevant policies, and be able to engage in policy-related investments. Opportunities are provided for participants to obtain financial support related to relevant policies, such as subsidies for large-scale farming, subsidies for standardized farm construction, and subsidies for biogas digester installation. Therefore, policy-oriented training is conducive to livestock farmers’ installation of biogas digesters.
Technology-oriented training is mainly provided by technical experts. The goal of this type of training is to explain the relevant technology, break the promotion obstacles of new technologies through knowledge dissemination, and improve the technical ability or management level of participants who adopt the technology with new equipment and/or facilities, as well as the operation and maintenance of the equipment and facilities [
37]. Participants can obtain timely technical support through both training and building relationships with relevant technical staff, or even long-term cooperation. Therefore, in the context of sustainable farming practices, technology-oriented training is also conducive to livestock farmers’ installation of a biogas digester.
Field-based training, also known in some countries as on-the-spot training, is another common type of training which provides experiential, field-based learning activities [
38]. In the agricultural sector, field-based training is generally held on farms with state-of-the-art sustainable farming practices. Through on-site visits and demonstrations, farmers participating in the training better understand the environment-friendly management practices and resulting effects. This can encourage the participants to adopt the same or similar management practices, such as installing biogas digesters to recycle manure.
In addition to the direct effects of training on participants, there are also indirect positive impacts via peer effects. Studies show that agricultural training can promote communication and information sharing among farmers [
39] by influencing each other’s farming decisions through an experience exchange where there are social effects between individuals [
40,
41]. Li et al. [
42] demonstrated that knowledge exchanges and transfers through peers and training show a significant and positive impact on rice farmers’ adoption of agricultural low-carbon technologies. In addition, for the installation of biogas digesters, in order to match the capacity of biogas digesters with the farming scale, some farmers cooperate with one another to install biogas digesters to jointly treat or assist in the treatment of livestock manure. In short, all kinds of training can change farmers’ cognition to varying degrees [
43], thereby affecting their decision-making.
There is extensive literature on the effectiveness of agricultural training programs. From the perspective of outcomes, existing studies show that agricultural training can contribute to higher agricultural productivity [
44], higher rural income and better livelihoods [
45], and sustainable food security [
37]. From the perspective of behavior-altering, agricultural training can affect the behavior of trainees. For example, training has been shown to affect the adoption of conservation tillage [
36], agrochemicals selection and application [
46], the adoption of improved cultivation practices [
47], soil fertility management practices [
48], and climate change adaptation strategies [
42]. Despite the potential benefits of the agricultural training programs, there are doubts about the effectiveness of such training due to poor training practices [
39], a lack of integrative agricultural communication [
49], or the inability to meet the actual education and training needs of farmers [
37,
50]. In particular, the effectiveness of training programs on biogas digester installation in the livestock sector has not been explored in previous research.
This study uses field survey data of beef cattle farmers in China to empirically examine the effectiveness of farmer training on beef cattle farms’ installation of biogas digesters. We hypothesize that training is effective in promoting livestock farmers to install biogas digesters to manage manure and that the more intense the training, the higher the effectiveness. The hypotheses are tested through the statistical modeling of primary farm-level survey data from a leading beef cattle production region in China. There are two major contributions of this study. First, existing studies on the installation of biogas digesters on livestock farms mainly employs case-study approaches with a technical perspective. This study fills a gap in the literature by looking into the behavioral aspect. Second, to our knowledge, this is the first study using primary farm-level survey data from a leading livestock production region to empirically examine the effectiveness of agricultural training on biogas facility installation.
4. Conclusions
Anaerobic digestion is one of the leading ways to manage livestock manure for energy production and to move towards carbon neutrality in the agricultural sector. Based on the field survey data of beef cattle farmers in China, this study empirically examines the impact of agricultural training on farmers’ installation of biogas digesters to manage livestock manure. The results show that training has a positive impact on both farmers’ willingness and the actual installation of biogas digesters, which indicates that training can effectively motivate farmers to install biogas digesters. In terms of the marginal effects, the impact of training on farmers’ willingness to install biogas digesters is stronger than that of actual installation. Furthermore, with the increase of training intensity, the probability is higher for farmers to install biogas digesters. For the control variables, the education level and farming experience of a farmer, as well as farm location, are found to also affect the installation of biogas digesters, among which the education level of a farmer is the most significant factor affecting the installation.
Based on the above findings, several policy implications are proposed for promoting anaerobic digestion for livestock manure management. First, agricultural extension and outreach programs should be developed to facilitate the training of livestock farmers and enrich the existing training content, such as policy interpretation and technical guidance. Second, since the education level of a farmer is the most important factor affecting the installation of biogas digesters, vocational education can be strengthened to improve the education level of farmers. In addition, incentives can be provided to encourage personnel with higher levels of education to engage in livestock farming. For example, China encourages highly educated groups, such as college graduates, to start agribusinesses in rural areas by implementing financial subsidies, financial credits, tax incentives, guarantee assistance towards start-up failure, etc. Lastly, because the livestock farming experience also affects the installation of biogas digesters, mentor-mentee programs that pair more-experienced livestock farmers with less-experienced ones can be developed to provide informal training and assistance to new farmers.