节点文献
畜禽粪便污染的农业系统控制模拟及系统防控对策
Research on Prevention and Control System of Livestock and Poultry Excreta
【作者】 柳建国;
【导师】 卞新民;
【作者基本信息】 南京农业大学 , 生态学, 2009, 博士
【摘要】 本文立足江苏农业面源污染成因调查与农户行为分析,基于农田畜禽粪便安全经济承载力和畜禽养殖污水生态处理技术,用循环经济的理念,建立了畜禽粪便污染的农业系统控制的动力学模型,运用MatLab和计算机仿真对姜堰市河横村畜禽粪便污染进行了农业系统控制模拟,从系统的角度提出畜禽粪便污染防控对策。主要研究内容与结果如下:1农田畜禽粪便安全经济承载力在大田生产条件下,重点研究水稻、大麦对氮、磷养分的利用吸收,通过测定和估算氮磷的富余量和富余率,分析土壤-作物系统处理粪便的能力。试验结果表明,在一定范围内,随着畜禽粪便施用量的增加,作物对氮磷的吸收量也随之增加,但是相邻处理间氮磷吸收量相差较小,因此随着畜禽粪便施用量的成倍增加,氮磷的损失量、损失率也在成倍增加。在一年时间里,两季作物最高带走氮368.4kg·hm-2、磷81.98kg·hm-2,为不让过多的氮磷流入周围水体造成二次污染,全年农田猪粪施用量不超过34.6t·hm-2比较合理;不同施肥量的产值分析表明,猪粪年施用量60-120 t·hm-2产值较高。综合生态环境、肥料利用效率、产量等多种因素,在不使用化肥的情况下,农田畜禽粪便安全经济承载力为35t·hm-2·a-1至60t·hm-2·a-1猪粪当量。2江苏省畜禽粪便污染负荷及评价1997-2006年,江苏省养殖业发展有明显两个阶段,1997-2003年是养殖业快速发展期,苏州、无锡2003年养殖规模比1997年分别扩大346%、300%,增加最少的南通市养殖规模还扩大了44%;2003年以后,江苏省养殖规模进入调整期,常州、南通、镇江三地市养殖规模有小幅度增长,南京、无锡、苏州等10个地市养殖规模呈下降趋势。2006年耕地年畜禽粪便污染实际负荷,无锡市最高(46.75 t.hm-2),其次是南京(41.59 t·hm-2),苏州以34.44 t·hm-2居第三位,淮安、扬州、镇江、宿迁负荷量较低,只有20 t·hm-2左右。以农田畜禽粪便安全经济最大承载力60t·hm-2猪粪当量,对2006年江苏省各地市耕地污染负荷进行评价,结果显示,无锡市警报值为0.78,畜禽粪便产生量对环境构成威胁,淮安、扬州、镇江、宿迁和泰州的警报值分别为0.31、0.34、0.34、0.34和0.38,畜禽粪便产生量对环境不构成威胁,其余地市处于稍有威胁状态。从江苏省省域范围来看,2006年江苏省畜禽粪便污染负荷为28.59 t·hm-2,其警报值0.47,处于稍有威胁状态低线。3畜禽养殖污水生态处理技术本文对畜禽养殖污水处理采用的是作物秸秆吸附拦截和水生植物净化相结合的净化方法。在试验室条件下,用4种不同长度的小麦秸秆吸附过滤畜禽养殖污水,吸附截留率一般在10-20%,分层状秸秆比整体状、棍断状、粉碎状三种形式能更好地吸附养殖污水中的氮磷。采用分层处理,处理90分钟时可以达到最佳处理效率,每kg秸秆对总氮和总磷的最佳吸附容量分别为286.42mg和110.81mg。水葫芦(饲料植物)、水花生(饲料植物)、香根草(湿地护坡植物)、水稻(农作物)四种水生植物漂浮生长在养殖污水中,30d对污水的净化率,水葫芦76-90%,水花生51-65%,香根草42-67%,水稻66-88%,净化能力大小顺序为,水葫芦>水稻>水花生>香根草。在高浓度污水(N含量97.3mg·L-1、P含量39.7mg·L-1)中,30d植物体重量增加率,水葫芦82.1%,水花生37.5%,香根草-3.2%,水稻4.6%,说明水葫芦适宜用于对高浓度养殖污水的净化,香根草不能用于对高浓度畜禽养殖污水的净化。30d试验表明,水稻、水葫芦和水花生每增加1kg生物量,平均净化污水中氮磷总量分别为48g、2.9g和2.5g。4畜禽粪便污染农业系统控制模拟通过对农田畜禽粪便安全经济承载力及畜禽养殖污水生态技术处理的研究,运用系统动力学的建模方法,对畜禽粪便污染的农业系统控制的过程假定和系统分析,利用MatLab工具和计算机仿真技术对模型进行了基于仿真实验的结构设计、参数和性能优化。通过对河横村畜禽粪便污染农业系统控制模型合理的结构设计与参数优化,设定系统的状态变量6个,并分别赋予理想的系统工作点值,以2007年为基准年,进行系统仿真实验,结果表明,系统可以从目前不太理想的初值,经过不到20年的时间和较小的波动,达到理想的稳定状态,即河横村从2007年开始,经过不到20年的时间,就可以达到协调可持续发展的要求。利用河横村历史数据(1991-2007)对系统模型有效性检验,6个状态变量的R2最小为0.8,最大0.94,平均为0.855,STD均较小,说明建立的畜禽粪便污染的农业系统控制模型是科学可行的。原发展模式(未加入生态工程)系统2030年的终值与加入生态工程并优化后的系统2030年的终值相比,未加生态工程的系统比加入生态工程的系统不仅经济指标明显下降,而且环境指标也较差,比如,未加生态工程的系统比加入生态工程的系统养殖规模少5.6%的情况下,周围水体中氮磷是后者的14倍。可见未加生态工程的系统经济发展不足,环境保护欠缺,不符合循环发展要求,而加入生态工程并优化后的系统符合可持续发展的要求。5农业面源污染原因调查与行为分析通过对江苏省高淳县、江阴市、江都市、姜堰市、阜宁县、灌南县等市县农村环境存在的问题和原因进行实地考察,并召开由政府相关部门、当地农民参加的座谈会。调查表明,苏中苏北农业面源污染与经济因素有关,尤其是苏北,环境保护意识不强和经济总量不足是造成农业面源污染的重要原因。通过对195农户调查,100%的农户都使用化肥,只有62.3%的农户愿意使用有机肥。对畜禽粪便处理方式,29%的农户随意抛弃,61%农户还田,10%的农户卖给有机肥厂。对于环境保护与污染治理的责任,62.1%的农户认为是政府的责任,33.8%的农户认为是企业的责任,4.1%的农户认为是个人责任,说明环境保护与治理,政府承担主要责任。农户对环境保护支付意愿,4%的农户不愿意出资,46.9%的农户表示看情况而定,49.1%的农户愿意为治理环境出资,最高可承受的费用是年收入的2%,平均支付意愿是年收入的0.798%。生态意识度与农户年收入相关度0.928,与居民文化水平相关度0.94因此,发展地方经济,加强环境保护教育,提高人们文化水平,使农民具有环保意愿的驱动力,对畜禽粪便污染的控制具有重要的意义。6畜禽粪便污染的防控对策基于畜禽粪便污染原因及农户环保行为分析和畜禽粪便污染的农业系统控制模拟,从系统动力学出发,提出“政策引导、规模协调、技术配套、机制完善”的畜禽粪便污染防控对策。
【Abstract】 In line with pollution condition of livestock and poultry excreta in Jiangsu province, dynamic model of control on agricultural system of livestock and poultry excreta was built with circular economy idea as key point by using of safety economic bearing-capacity on field’s livestock and poultry excreta as well as ecological treatment of breeding sewage; control on agricultural system of pollution by livestock and poultry excreta in Heheng village of Jiangyan City was simulated by using of MatLab and computer simulation; strategies of prevention and control were put forward from the point of system. The main research contents and results are as follows:1. Safety economic bearing-capacity on field’s livestock and poultry excretaField-experiment was adopted to conduct research on the capability of rice and barley absorbing N and P. We analyzed the livestock and poultry deject disposal capability of crop by determining and estimating losing amount and ratio of N and P in soil. The result showed that, in a certain range, amount of crop absorbing N and P rose with increasing of livestock and poultry deject using. But there was no significant difference between each treatment, which means losing amount and ratio of N and P increased by times with increase of livestock and poultry deject using. Crop absorbed 368.4kg/hm2 N and 81.98kg/hm2 P from soil at most in one year, under 34.6t-hm-2 pig feces using amount per year was suitable to prevent secondary pollution that caused by the influx of excessive N and P to around water system. Basing on the analysis of production value of different fertilizer using amount,60-120 t·hm-2 per year was optimal. Therefore, considering integrated factors including ecological environment and fertilizer using ratio as well as yield, the safety economic_bearing-capacity on field’s livestock and poultry excreta was 35-60 t·hm-2·a-1·a pig feces equivalent on the precondition that no other fertilizer was used.2. Evaluation on pollution load of livestock and poultry excreta in Jiangsu provinceDevelopment of raising industry in Jiangsu province consisted of two phases. During the first speed development phase from 1997 to 2003, breeding scale of Suzhou and Wuxi in 2003 expanded 346%and 300%compared to 1997, respectively, even 44%in least expanded Nantong. In adjustment phase after 2003, breeding scale in Changzhou, Nantong, and Zhenjiang increased in small range, while declined in 10 cities like Nanjing, Wuxi and Suzhou. Wuxi’s 46.75t/hm2 ranked the foremost real load of farmland livestock and poultry excreta in 2006, following as Nanjing (41.59t·hm-2) and Suzhou (34.44t·hm-2). Load value around 20t·hm-2 of Huaian, Yangzhou, Zhenjiang and Suqiang were relatively lower than that of other cities.Pollution load of each city in Jiangsu province were evaluated with 60 t·hm-2 as the alarm value of the safety economic bearing-capacity on field’s livestock and poultry excreta. Results showed that environment of Wuxi(0.78) was in danger with livestock and poultry excreta volume, Huaian(0.31), Yangzhou(0.34), Zhenjiang(0.34), Suqiang(0.34) and Lianyungang(0.38) were out of danger and the rest cities were in less polluted position.Pollution load of livestock and poultry excreta of overall Jiangsu province in 2006 was 28.59t·hm-2, warning value was 0.47, being in less threatened position.3. Technology of ecological treatment on sewage of breeding of livestock and poultryTreatment combined with grain straw and hydrophytes was adopted to purify breeding sewage in this study.Under laboratory conditions, livestock excrement waste water was purified by adsorbing on 4 different length Straws of wheat. The results showed that they have interception rates 10-20%, among which absorption of N and P in layer form was better than those of in whole, fracture, or ground form. When using the layer form, the optimum treatment time is 90 min, at which point the best absorption quantity of total N and total P in per Kg straw are 286.42mgand 110.81mg respectively.Four hydrophytes, Eichhornia crassipes, Alternanthera philoxeroides, Vetiveria zizanioides and rice, were planted in breeding solid water to research their purification capacity. The result showed that purification ratio of Eichhornia crassipes, Alternanthera philoxeroides, Vetiveria zizanioides and rice were 76-90%,51-65%,42-67% and 66-88%, respectively in 30 days. The purification capacity of these 4 hydrophytes was arranged as follow:Eichhornia crassipes> rice> Alternanthera philoxeroides> Vetiveria zizanioides. In high concentration sewage (97.3mg·L-1 N,39.7mg·L-1 P) absorption, the increasing ratio of Eichhornia crassipes, Alternanthera philoxeroides, Vetiveria zizanioides and rice were 82.1%,37.5%,-3.2%and 4.6%, respectively in 30 days, which showed that Eichhornia crassipes was suitable for purifying high concentration solid water while Vetiveria zizanioides was not.The experimental in 30 days showed that when the biomass of rice, Eichhornia crassipes, Alternanthera philoxeroides increased 1Kg, the mean purification quantity of total NP were 48g,2.9g,2.5g respectively.4. Control simulations of Agricultural System of livestock and poultry excretaBased on the study of safety economic bearing-capacity on field’s livestock and poultry excreta as well as ecological treatment of breeding sewage, researches such as optimizing construction, parameter and performance of simulation model and self-motion were conducted with MATLAB and computer simulation by using dynamic model, process hypothesis, and system analysis. System simulation was experimented by optimizing construction and parameter of control model of agricultural system of livestock and poultry excreta in Heheng village when hypothesized 6 State Variables, an ideal working-point-value of system, basic year 2007 for comparison. The results showed that the system had become an ideal Stability state from an unsatisfied initial-value when experienced less than 20 years and little fluctuation, that is to say, the development of Heheng village can reach a requirement of sustainable development before 2027.Text of model efficiency by earlier data(1991-2007) of Heheng village demonstrated that it is feasible to establish the control model of agricultural system of livestock and poultry excreta (R2min=0.8, R2max=0.94, v=0.855, n=6).Compared to optimizing system, economic index in 2030 predicted by former model system declined significantly, breeding scale of former system was smaller than optimizing system, and crop yield reduced 15%. On the precondition of 5.6%reduction of breeding scale, NP in water of former system was 14 times higher than optimizing system. Development system without ecological project brought less economic interests and more environmental pollution, which couldn’t meet requirement of circular agriculture. On the other hand optimizing system with ecological project was an ideal development model that met requirement of sustainable development.5. Investigation and Analysis of Behavioral Factors of Agricultural Non-point Source PollutionThe problems and factors existing in rural environment of Gaocun, Jiangyin, jiangdu, jiangyan, Funing, Guannan in Jiangsu were analyzed by the on-site investigation and the informal discussion meeting. The results showed that factors of agricultural non-point source pollution in Mid-Jiangsu or north-Jiangsu were relation with socioeconomic, especially the absence of environment protection and Economic aggregate in north-Jiangsu.Questionnaires covering 195 farmers showed that all the farmers used chemical fertilizer, only 62.3%farmers preferred organic manure.29%farmers abandoned livestock and poultry excreta,61%farmers returned them to fields,10%farmers sold them to organci fertilizer factory.62.1%farmers thought government should be responsible for rural environmental control,33.8%farmers thought it is enterprise’s responsibility,49.1%, only 4.1%farmers thought it is them-selves responsibility. The above results showed that government should abandon the main responsible for rural environmental control.4%farmers were un Willingness to pay for environment protection; 46.9%farmers depended on the pay situation is; 49.1%farmers were Willingness to Pay for environmental control, of which the highest bearing pay is about 2%total annual income and the mean pay is about 0.798%total annual income. The correlation between farmer’s environmental awareness and average net income per year was 0.928, and the correlation between environmental awareness of rural residents and their educational level was 0.94 that higher than correlation of their income level. Therefore, several measures, such as developing local economy, enhancing environmental education, raising people’s educational level, would make farmers be willing to protect environment, which was important to control livestock and poultry excreta pollution.6. Strategies of prevention and control on pollution of livestock and poultry excretaBased on the pollution factors of livestock and poultry excreta, the behaviors analysis of farmers’environmental protection, and the control simulations of agricultural system, strategies of prevention and control on pollution of livestock and poultry excreta of "policy-guidance, scale-harmonious, matching-technology, mechanism-perfection" were put forward from the point of system dynamic.
【Key words】 livestock and poultry excreta; safety economic bearing-capacity; agricultural system; computer emulation; strategies;