【作者】 贾伟；

【导师】 陈清； 李彦明； David Chadwick；

【作者基本信息】 中国农业大学 ， 植物营养学， 2014， 博士

【摘要】 我国规模化、集约化养殖业的迅猛发展导致畜禽粪便数量的大量增加,导致部分地区出现不同程度的环境问题。实现畜禽粪便中的养分从产生到土地合理施用的整个循环利用过程,不仅可避免环境污染,而且在资源节约等循环产业发展方面有很大的吸引力,因此了解我国集约化养殖废物产生的数量和空间分布,对以环境友好为目标,不断提高粪肥养分资源管理措施,实现畜禽养殖业可持续发展至关重要。本研究通过收集相关畜禽排泄参数并结合畜牧年鉴统计数据,计算我国畜禽粪便及养分产生数量和空间分布特征；结合当前主要的粪肥处理模式,分析我国有机废物可用于堆肥原料的潜力；结合农户、养殖场调研以及文献资料,剖析我国主要典型规模化养殖区粪肥管理现状和存在的问题；以北京郊区为例,对典型高畜禽密度养殖区的有效粪肥养分供应和替代化肥潜力进行了情景分析；以磷素为例,采用GIS数据分析了典型规模化畜禽养殖区可接受粪肥施用的农田面积,估算了2030年的畜禽粪肥中磷素产生量、不同粪肥施用管理模式对北京地区土壤Olsen-P变化的影响,从环境友好角度分析未来可施用粪肥的农田面积数量变化。主要结果如下：1.利用作物谷草比、畜禽排泄量等系数和2009年公布的国家统计数据,估算了年度的有机废物产量和养分资源量潜势。结果表明,畜禽粪肥和作物残茬是有机废物的主要来源,其中粪肥占到总有机废物的50%(以干重计),粪肥总重为6.96亿t。作物残留物占到总有机废物的45%,其总重为7.68亿t。有机废物碳(C)、氮(N)、磷(P)、钾(K)养分量分别为5.55亿t,0.20亿t,0.04亿t和0.22亿t。然而,仅有26%的作物残茬,25%的畜禽粪便,2%的城市有机垃圾和48%城市生活污泥被可作为再利用堆肥原料,这相当于为作物生产贡献了1.35亿tC,0.05亿tN,0.01亿tP,0.05亿tK。考虑中国当前的堆肥市场,特别是有必要加强高负荷区域的堆肥生产,以促进有机废物的循环使用。2.尽管我国养殖业向规模化发展,但是机械化水平差限制粪肥的运输和施用。不同地区畜禽养殖产生粪便处理方式差异明显。北京市规模化养殖场清粪方式98%为干清粪,76%的的固体粪便在室外露天堆置,由于地面裸露,极易在降雨后引起粪肥养分的径流或淋洗损失。京郊规模化养殖场64%的固体粪便以通过出售粪肥还田利用,而90%的液体粪便被丢弃无法利用。农户养殖粪便处理,北京14%和江苏67%为堆肥和沼气发酵。从堆肥的工艺来看,36%的企业采用条垛堆肥系统,而且74%的企业采用机械翻堆,64%的堆肥企业发酵周期为15-30天。鸡粪、猪粪、牛粪堆肥过程均有高量的C、N损失,C和N素损失比例范围分别为53.8-54.7%、16.3-54.3%。3.针对京郊养殖业和农用地面积现状,结合调研、收集畜禽养分排泄系数和农田养分需求等参数,估算京郊固液粪便养分资源现状及其替代化肥的潜力。结果表明：京郊畜禽固液粪便中N、P、K养分量分别为5.87、2.13、2.98万t,其中固体粪便N、P、K养分分别为4.31、2.03和1.97万t,京郊畜禽固液粪便可分别满足农田N、P、K养分需求量的99.3%、185.2%、62.7%。大部分区县粪肥中P养分产生量超过作物P需求量,粮田秸秆还田可带入的N、P、K养分分别为1.10,0.16和1.50万t,情景分析表明在秸秆还田条件下,按照磷素平衡原则估算本地区所能消纳的粪肥所带入N、P和K养分数量分别为1.83、0.99和1.03万t,同时需要补充N、K化肥分别为2.98和2.22万t,其余粪肥则需经过堆肥化处理并输往外地。经过堆肥处理,固体粪肥可提供的N、P、K养分分别下降了23%、11%和12%,外输固体粪肥堆肥可进一步减少农田氮磷负荷以及可能的环境风险。4.除坡度大于25度的农田和水源保护区附近农田不适合施用粪肥外,土壤测试磷水下决定了农田土壤消纳粪肥中磷素的潜力。京郊不同粪肥磷管理和粮食作物的种植比例对土壤测试磷变化的影响情景分析结果表明：当前粪肥产生已造成了高量的磷素盈余,且单位耕地下均粪肥磷载荷为53kg P/hm2,11%的农田不适合继续施用磷肥这是因为土壤高磷含量超过了磷环境风险的临界值。增加粮田中施用粪肥磷的比例可以减少每年的磷盈余,这样继而减轻果园和菜地磷素负荷。预计到2030年粪肥磷的年总产生量会增加到3.08万t,粮田、果园和菜地的土壤速效磷分别会增加到54.6、106.1和131.7mg/kg。磷素平衡管理方法可维持所有农田环境安全的低水平土壤速效磷,但增加京郊外运粪肥的数量。5.从政策角度,合理利用粪肥养分资源并减小环境磷风险的重要建议包括：采用平衡饲料管理减少养分排泄磷；采用合理的清粪工艺和固液分离处理,以减少废水磷排放,提高固体粪便磷收集率；采用堆肥处理减少粪肥体积,方便运输减小区域磷载荷；沼气处理可提供能量并减少N、P损失；施用粪便时保持合理的粪肥和化肥磷比例及施用量,减少土壤磷养分累积、避免淋洗或径流过程中磷养分损失。更多还原

【Abstract】 With the significantly rapid development of the intensive livestock farm, the increased amount of manure production can cause environmental problems. It is urgent to rationally use these livestock manure resources. Optimized manure application could avoid the environment pollution and appeal to the rapid development of resource conservation and recycling industry. It is very important to know the amount of manure generation and spatial distribution from the intensive livestock breeding, and to constantly improve the measurements of manure nutrient management at the aim of environment friendly in order to achieve the development of sustainable intensive livestock production. In this study, the amount of livestock manure and nutrients generation was calculated by the related excretion coefficient and livestock numbers from the statistical yearbook. Meanwhile, spatial distribution of manure and nutrient generation was identified by GIS map. And combined with current main mode of manure management, the potential of organic wastes used as composting feedstock was analyzed by using the theoretical assumed value. Meanwhile, the status and existed problems of manure management in typical high livestock density regions were analyzed by farmer questionares interviewing from crop system and livestock farm combined with literature reviews. In addition, available manure nutrient supply and fertilizer substituted with manure were carried out in the typical regions with high livestock density, Beijing was studied by scenario analysis as a sample. Finally, taking an example of manure phosphorous utilization, the ’landbank’ of intensive livestock regions for recieving manure application was calculated using data of GIS map. And from the environmental friendly perspective, it should determine the change of ’landbank’ for manure application by estimating the amount of livestock manure generation in2030, and regional soil Olsen-P dynamic influenced by different mode of manure amangement in2030. The main results were as follows:1. The disposal of organic wastes (OW), i.e. crop residue, livestock manure, municipal organic wastes (MOW) and municipal domestic sludges (MDS) into the environment lead to water and land pollution and mean the waste for plant growth. Composting is the optimum choice to recycle these wastes. In this study the annual production of organic wastes and potential nutrient resources were estimated using coefficients of crop and livestock excretion and related national statistical data by official documents in2010. As the dominant wastes, the amounts of manure,50%of total OW (dry weight basis), and crop residue,45%of total OW (dry weight basis), were696megatonne (Mt) and768Mt, respectively, as estimated by statistical analysis models. The amounts of C, N, P and K in OW were555.3,20.1,4.2and21.9Mt, respectively. However, only26%of crop residue,25%of manure,2%of MOW and48%of MDS were potentially re-utilized as compost feedstock, which contributed to135.4Mt C,5.0Mt N,1.1Mt P and5.2Mt K to the nutrient pool for crop production. Compared to the current proportion of compost in manure market of China, it is necessary to strengthen the composting production in the region with high manure load to increase recycling of organic waste.2. Although the trend is the development of intensive livestock farming in China, the difference of mechanization level in this process of developing intensive livestock farming will limit manure transportation and application. The manure management methods in different regions of livestock and poultry breeding were significantly different. In Beijing, the manure cleaning method for intentsive livestock farm was98%of the faeces removal (’Ganqingfen’in Chinese). While,76%of solid manure was stored with the outdoor and open air. It easily cause the runoff or leaching losses for manure nutrients in the rainday because of bare ground.64%of solid manure from intensive livestock farm were to sell directly and to apply to field directly in Beijing.90%of liquid manure should be discarded and not be recycled. For rural household manure management,14%and67%of solid manure treated by compost and biogas was in Beijing and Jiangsu, respectively. From the point of view of composting process,36%of composting enterprises was windrow composting system.74%of composting enterprises was mechanical turning, and64%of composting enterprises was15-30days for the finished composting fermentation period. High porprotion of C, N losses was existed in the chicken, pig, cattle manure composting. In addition, the range of C and N loss in the composting was53.8-54.7%and16.3-54.3%, respectively.3. In this study, considering the current status of livestock farming and arable land area in Beijing suburbs, the current situation of organic waste resources in livestock farming and its substituting potential for chemical fertilizer were estimated through livestock farm survey, the collection of livestock excretion coefficients and crop nutrients demand through literature and related statistical data. The results indicated that total amounts of N, P, K contained in solid manure and liquid manure production were58.7×103t N,21.3×103t P,29.8×103t K, which included43.1×103t N,20.3×103t P and19.7×103t K in solid manure, respectively. Total amount of N, P, K contained in solid manure and liquid manure could be satisfied with99.3%,185.2%and62.7%of the total crop requirement of N, P, K in Beijing in2011, especially the amount of generated manure P has exceeded total crop P requirement in most districts of Beijing. Moreover, cereal straw returned to soil could bring equivalent to11.0×103t N,1.6×103t P, and15.0×103t K to arable land. In the scenario analysis, the allowable amount of NPK nutrients in livestock manure to be applied to arable land were only18.3×103t N,9.9×103t P, and10.3×103t K, respectively, based on P balance method, if considering cereal straw incorporation. Additional29.8×103t N and22.2×103t K were needed to be supplied with chemical fertilizers to meet crop demand. P surplus sourced from organic waste obligated the solid manure to be composted and transported to the neighbor regions with inadequate P supply. Total N, P, K nutrients contained in composted solid manure decreased by23%,11%and12%after aerobic composting, and the transportation of commercial composted solid manure exported out of Beijing will further reduce N and P load in arable land and consequently reduce the risk of environmental pollution.4. Rapid growth in the intensive peri-urban livestock farming has led to excessive manure P load in urban regions of China, with increasing risk in watercourses eutrophication. It is urgently to assess the potential’landbank’ available to receive the generated manure considering environmental protection. In this study, the potential distribution of manure P to arable land in Beijing through estimating soil testing P changes with P accumulation, excluding the arable land with the slope>25°, and water protection zones. The influences of soil testing P changes related to environmental risk on potential utilization of manure phosphorus were investigated under different scenarios on manure P management and proportion of cereal crop planting. Results showed that current generated manure has resulted in high P surplus, and the average manure P load rate to arable land was53kg P ha-1, with11%of arable land was unsuitable for continuous P application due to high soil P levels which exceeded P environmental risk threshold. Scenario analysis results suggested that, increasing the proportion of manure applied to cereal fields reduced the annual P surplus, which in turn alleviated the over accumulation of P in orchard and vegetable fields. The annual total manure P excretion was expected to increase to30.8Gg in2030, and soil Olsen-P level were increased to54.6,106.1and131.7mg kg-1in cereal, orchard and vegetable land, respectively. However, the balanced P managing approach could maintain the soil Olsen-P in much lower level, i.e.24.3,22.0and27.3mg kg-1in cereal, orchard and vegetable land. Applying manure to cereal field with relatively low Olsen-P level, and exporting surplus manure out of the peri-urban regions are regarded as the key ways to minimize environmental P risk.5. From a policy perspective, important suggestions were used in the optimized utilization of manure nutrient resources and minimlization of the environmental phosphorus risk including:Using balanced feed management to reduce nutrient phosphorus excretion; Adopting reasonable manure cleaning processing and solid-liquid separation process to reduce wastewater phosphorus emissions; Increasing the collection rate of solid manure phosphorus; Reducing manure volume and getting convenient transportation of manure by composting in order to decrease regional phosphorus load; Energy supply and reducing the N, P loss by biogas processing; When applying manure, to maintain the reasonable proportion and rational amount of manure and chemical P input in order to reduce the soil phosphorus accumulation and phosphorus losses in the process of leaching and runoff.更多还原