Nitrous oxide, methane, and ammonia emissions from cattle excreta on Brachiaria decumbens growing in monoculture or silvopasture with Acacia mangium and Eucalyptus grandis
Nitrous oxide, methane, and ammonia emissions from cattle excreta on Brachiaria decumbens growing in monoculture or silvopasture with Acacia mangium and Eucalyptus grandis
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DOI：
10.1016/j.agee.2020.106896
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发表时间：
2020-06-15
影响因子：
6.6
通讯作者：
Chizzotti, Fernanda H. M.
中科院分区：
文献类型：
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作者：
Bretas, Igor L.;Paciullo, Domingos S. C.;Chizzotti, Fernanda H. M.
我们量化了一氧化二氮（N2 O），甲烷（CH 4），和氨（NH3）的排放量从牛尿和粪便补丁上生长在一个长期的silvopasture（SPS）或单作（MONO）在每年的雨季和干燥期在巴西西南部的臂形草斜卧。我们假设，SPS中由树木提供的浓密树荫和枯枝落叶以及牧草质量引发的微环境变化会影响牛排泄物的温室气体排放。两个田间试验（雨季和旱季）进行了使用手动封闭静态箱在3 × 2析因方案，对应于三种排泄物类型（尿液，粪便，和对照无排泄物）和两个牧场系统（SPS和MONO），在区组设计，三个区组和两个重复每个区组（n = 6每个处理）。总体而言，SPS处理的N2 O和CH 4排放通量高于MONO处理。值得注意的是，氮损失的形式N2 O不超过0.10%，除了N2 O排放量从尿沉积在雨季在SPS（0.39%的应用N）。牛粪也是CH 4的一个来源。在雨季，SPS下观测到最高通量，但排放量一般较低，排放率< 0.1千克CH 4头（-1）年（-1）。氨挥发损失最高的是MONO下的尿液，在雨季和旱季分别占施氮总量的8.3%和17.1%。我们的研究结果表明，N2 O，CH 4和NH3排放量从牛的牧场系统，排泄物类型和季节的影响。在长期SPS中，N2 O和CH 4排放增加，而NH3损失减少。
We quantified nitrous oxide (N2O), methane (CH4), and ammonia (NH3) emissions from cattle urine and dung patches on Brachiaria decumbens growing in a long-term silvopasture (SPS) or in monoculture (MONO) during the annual rainy and dry periods in southwest Brazil. We hypothesized that microenvironmental changes triggered by dense shade and litter, provided by trees, and pasture quality in SPS would affect greenhouse gas emissions from cattle excreta. Two field trials (rainy and dry season) were carried out using manual closed static chambers in a 3 x 2 factorial scheme, corresponding to three excreta types (urine, dung, and control without excreta) and two pasture systems (SPS and MONO), in a block design with three blocks and two replicates per block (n = 6 per treatment). Generally, N2O and CH4 fluxes were higher in SPS than in MONO. Notably, N losses in the form of N2O did not exceed 0.10 %, except for N2O emissions from urine deposited during the rainy season in SPS (0.39 % of applied N). Cattle dung was also a source of CH4. The highest fluxes were observed under SPS during the rainy season, but emissions were generally low, with emission rates < 0.1 kg CH4 head(-1) yr(-1). The highest N losses by NH3 volatilization were observed for urine under MONO, amounting to 8.3 % of total N applied during the rainy season and 17.1 % during the dry season. Our results demonstrate that N2O, CH4, and NH3 emissions from cattle are influenced by pasture system, excreta type, and season. N2O and CH4 emissions increase in long-term SPS, while NH3 losses reduce.