奶牛运动场温室气体排放规律与排放过程模拟研究

发布时间：2018-01-04 17:31

  本文关键词：奶牛运动场温室气体排放规律与排放过程模拟研究　出处：《中国农业大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 奶牛运动场 静态箱 温室气体 表面风速 地面类型

【摘要】：舍外运动场是我国普遍采用的奶牛养殖设施,大量粪污滞留在运动场上,成为了奶牛场粪便管理过程中温室气体的重要排放源。受限于检测技术,我国尚缺乏运动场气体排放的基础数据和相关规律,难以准确地估计运动场的气体排放量,也无法制定目标性的减排策略。针对上述问题,本研究选取了应用较广的静态箱法,探索了关键因素对其检测精度的影响,并通过优化设计的静态箱研究了奶牛运动场和露天堆粪场的温室气体排放规律。通过运动场气体排放过程的实验室模拟,本研究分析了关键因素对其温室气体和氨气排放的影响并构建了素土运动场上粪便的CH4排放估算模型。本研究的结果主要如下：(1)静态箱可较好地应用于低排放量时开放源气体排放的检测,但普遍表现为低估,实际排放量越高,检测结果越准确。对于固体排放源,静态箱的底面直径对其测试结果无显著影响(P0.05),但高度会显著影响其准确度(P0.05)。箱内设有循环气路且不开启压力平衡口时,是否使用风扇及风扇转速的大小对静态箱的检测结果无显著影响(P0.05)。箱内风扇的使用会使得箱内相对于外界呈正压状态,当压力平衡口开启时,风扇的使用会造成额外的正压,降低检测准确度。推荐采用循环气路进行箱内气体混合。(2)清粪频率为1次·天-1时,立砖地面的运动场CO2、CH4和N20排放量分别为137.5±64.7、0.45±0.21和0.13±0.08 kg·hd-1·yr-1。由于粪污量的不同,卧床区的气体排放量显著高于走道区(P0.05)。清粪后,运动场CH4排放量显著降低(P0.05),但N20排放量却显著升高(P0.05),且降雨会促进N2O的排放。露天堆粪场CO2、CH4和N20的排放量为858.9±64.7、8.5±5.4和2.3±1.1 kg·hd-1·yr-1。整个粪便管理过程中CH4和N20的排放量分别为9.0 kg·hd-1·yr-1和2.75kg·hd1·yr-1。(3)空气温度和表面风速的增加会促进运动场上CO2、CH4、N2O和NH3的排放。CH4对于25-35℃间的温度变化更敏感,而其它气体则对于15-25℃之间的温度变化更敏感。NH3的排放对较低风速时的变化更敏感。(4)清粪前,立砖地面的NH3和35℃时的CO2排放速率显著高于素土地面(P0.05),而CH4和N20的排放速率则不存在显著差异(P0.05)。清粪后,素土地面的CO2和NH3排放速率高于立砖地面(P0.05)。研究初步推断：由于养分下渗,素土地面延缓了粪便CO2和NH3的排放,并在清粪后导致更高的排放速率,形成二次排放。(5)运动场粪便温度与空气温度存在线性相关,当粪便温度不可获得时,可采用空气温度估计,估计误差平均为2%。不同温度和风速下,运动场地面上CO2与CH4的排放呈指数相关关系(P0.05)。素土地面上,表面风速与CH4排放量呈指数相关关系(P0.05)。
[Abstract]:Outdoor sports ground is a widely used dairy cattle breeding facility in China, a large number of feces remain on the sports ground, has become an important source of greenhouse gas emissions in the process of dairies excrement management, which is limited by the detection technology. Our country still lacks the basic data and related laws of the stadium gas emission, it is difficult to accurately estimate the stadium gas emissions, nor can we formulate the target emission reduction strategy. In this study, the static box method, which is widely used, is selected, and the influence of key factors on the detection accuracy is explored. The greenhouse gas emission law of dairy cow sports ground and open pit manure yard was studied by the optimized static box, and the laboratory simulation of the gas emission process of the sports ground was carried out. In this study, the effects of key factors on greenhouse gas and ammonia emissions were analyzed, and the CH4 emission estimation model of feces in the field was constructed. The results of this study are as follows: 1). The static box can be applied to the detection of open source gas emission at low emission level. However, it is generally underestimated, the higher the actual emissions, the more accurate the test results. For the solid emission source, the diameter of the bottom surface of the static box has no significant effect on the test results (P0.05). However, the height will significantly affect the accuracy of the P0.050.When the box is equipped with circulating gas and does not open the pressure balance port. The use of fan and fan speed has no significant effect on the test results of the static box. The use of the fan in the box will cause a positive pressure in the box relative to the outside, when the pressure balance opening. The use of fan will cause extra positive pressure and reduce the accuracy of detection. It is recommended that the cycle gas route be used for tank gas mixing.) the defecation frequency is 1 路days-1:00, and the CO2 of the sports ground with brick floor is recommended. The emissions of CH4 and N20 were 137.5 卤64.7c0.45 卤0.21 and 0.13 卤0.08kg 路hd-1 路yr-1, respectively. The gas emission in bed rest area was significantly higher than that in walkway area (P 0.05). After defecation, the CH4 emission of sports ground decreased significantly, but the emission of N20 increased significantly (P 0.05). The emissions of CO _ 2C _ 4 and N _ (20) from open pit dump were 858.9 卤64.7. 8.5 卤5.4 and 2.3 卤1.1 kg 路hd-1 路yr-1. The emissions of CH4 and N20 in the whole fecal management process were 9.0, respectively. Kg 路hd-1 路yr-1 and 2.75 kg 路hd1 路yr-1. 3) the increase of air temperature and surface wind speed will promote CO2 on the sports ground. The emission of Ch _ 4N _ 2O and NH3. Ch _ 4 is more sensitive to the temperature change between 25 and 35 鈩，

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