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ISBN 13 : 9789464472660
Total Pages : 0 pages
Book Rating : 4.4/5 (726 download)
Book Synopsis Improving Manure Management by :
Download or read book Improving Manure Management written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animal manure was a scarce and valuable resource in history. However, with the relatively cheap and easy handle synthetic fertilizers becoming easily available, livestock manure has turned from a resource into a waste or a pollutant to the environment, especially in industrial size farms or regions with high livestock density. Chinese livestock production has been developing quickly towards specialized intensive production in recent years. Most of the intensive farms has little or no cropland, which making manure management and utilization complex and difficult. The large amount of manure excreted and unproperly managed has cause a lot of social and environmental problems such as ammonia (NH3) emissions, greenhouse gas (GHG) emissions and water eutrophication. These increasing environmental problems have attracted attentions from scientists and governments. Many researches have been conducted and several regulations have been announced aiming at solving the problem. However, livestock farmers as one of the stakeholders in the management process are usually overlooked by the researches and regulations. Their adoption of techniques, and the drivers and barriers for them to use advanced techniques are unknown in China, which making the effectiveness of the regulations very limited. Therefore, the objectives of this PhD thesis include: i) to understand the adoption of manure management techniques and the drivers and barriers for those adoptions; ii) to estimate the impact of current management and explore options to mitigate the negative impacts. The work was mainly conducted with farm surveys and farmers’ interview on intensive dairy and poultry farms in Hebei and Shandong provinces, which were the major livestock production areas in China. With this survey data, in Chapter 2 the adoption rate of manure treatment techniques was analysed. Solid-liquid separation, anaerobic digestion, and composting were the only three techniques found in the survey. For dairy farms, 39% of the farms were equipped with solid-liquid separator, another 13% with anaerobic digestor and 6% with composting. However, most of the equipment were not used in practice and the actual operational rate was very low. For poultry farms there were almost no treatment at all. Interviews with farmers revealed that subjective norms from social referents, particularly from government agencies, were the main driver for the adoption of treatment techniques. However, the financial burden and technique failure hinder the adoption in practice. Even though Chinese government provided subsidies for the construction cost, the high operational cost and the bad manure market make the cost and the benefit unbalanced. Farmers therefore had low intentions to use these techniques. Chapter 3 focused on crude protein (CP) content in animals’ diet ration, because CP content determines nitrogen excretion in manure. When CP content exceed a certain level, animal productivity cannot increase further but N excretion in manure increases quickly. Therefore, low protein feeding is suggested by many researches as an effective method to reduce N excretion. Collected samples from mixed diet rations show that the mean CP content of animals’ diet ration was close to literature recommendations. However, there were large variations among farms, which indicates that there are still potentials to reduce CP content on some farms. Feeding companies actually defined the feed ingredients and nutritional values of animal diet rations. Farmers knew little about the importance of protein and the crude protein content of their animal rations. Speaking of low protein feeding, farmers were worried about the potential negative impacts on their production and financial risks. The results indicate that implementation of low protein feeding needs the active involvement of feeding companies, and more trainings are needed to help farmers understand feed protein better. In chapter 4 a model was developed to quantify the N and P flows based on mass balance approach. With the manure management information in each step collected from the farm survey, N and P flows in the management chain were quantified. On average 197 kg N and 30 kg P were excreted per cow per year (including young stock) and there was a substantial variation among the farms in NUE (53±20%) and PUE (84±22%) at farm level. Effects of management technologies varied greatly among farms; increases in farm-level NUE ranged from 0-53% and for PUE from 0-79%. Improving manure storage and treatment technologies and increasing manure export had relatively large effects on farm-level NUE and PUE and nutrient losses, while effects of low-protein feeding were limited. In chapter 5 the relationship between livestock density and soil P content was analysed at county and farm levels. Relationship between livestock density and soil P content was found to be insignificant at county level with the statistical data. However, at the farm level, livestock farms with cropland tended to have higher P content than crop farms without livestock in topsoil, mainly because that livestock farms with cropland tended to apply excessive amount of manure to cropland. The results indicate that manure was over applied from livestock farms but were not well utilized from crop farms. The results from this thesis point to the need for improved manure utilization in cropland, for developing a functioning ‘manure market’ with the involvement of middlemen, and for manure application limits for cropland on livestock farms. Hopefully, this thesis will contribute to improving manure management at farm level and to improving the sustainability of agriculture in practice.
