Livestock manures are broadly used in agriculture to improve soil quality. However, manure application can increase the availability of organic carbon, thereby facilitating methane (CH4) production. Cattle and swine manures are expected to have different CH4 emission characteristics in rice paddy soil due to the inherent differences in composition as a result of contrasting diets and digestive physiology between the two livestock types. To compare the effect of ruminant and non-ruminant animal manure applications on CH4 emissions and methanogenic archaeal diversity during rice cultivation (June to September, 2009), fresh cattle and swine manures were applied into experimental pots at 0, 20 and 40 Mg fresh weight (FW) ha−1 in a greenhouse. Applications of manures significantly enhanced total CH4 emissions as compared to chemical fertilization, with cattle manure leading to higher emissions than swine manure. Total organic C contents in cattle (466 g kg−1) and swine (460 g kg−1) manures were of comparable results. Soil organic C (SOC) contents were also similar between the two manure treatments, but dissolved organic C (DOC) was significantly higher in cattle than swine manure. The mcrA gene copy numbers were significantly higher in cattle than swine manure. Diverse groups of methanogens which belong to Methanomicrobiaceae were detected only in cattle-manured but not in swine-manured soil. Methanogens were transferred from cattle manure to rice paddy soils through fresh excrement. In conclusion, cattle manure application can significantly increase CH4 emissions in rice paddy soil during cultivation, and its pretreatment to suppress methanogenic activity without decreasing rice productivity should be considered.
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机译:畜禽粪便被广泛用于农业以改善土壤质量。但是,施肥可以增加有机碳的利用率,从而促进甲烷(CH4)的生产。由于两种牲畜的饮食和消化生理的对比,牛羊和猪粪在稻田土壤中具有不同的CH4排放特征,这是由于成分的固有差异所致。为了比较水稻种植期间(2009年6月至2009年9月)反刍动物和非反刍动物粪肥对CH4排放和产甲烷古菌多样性的影响,将鲜牛和猪粪分别以0、20和40 Mg的鲜重放入实验盆中(FW)ha -1 sup>在温室中。与化学肥料相比,粪肥的施用显着提高了CH4的总排放量,其中牛粪肥的排放量要高于猪粪肥。牛(466 g kg -1 sup>)和猪(460 g kg -1 sup>)粪肥中总有机碳含量具有可比性。两种粪肥处理之间的土壤有机碳(SOC)含量也相似,但是牛的可溶性有机碳(DOC)显着高于猪粪。牛的mcrA基因拷贝数显着高于猪粪。仅在牛饲养的土壤中检测到属于甲烷微菌科的产甲烷菌的不同种类,而在猪饲养的土壤中未检测到。产甲烷菌通过新鲜粪便从牛粪转移到稻田土壤。总之,施用牛粪肥可显着增加稻田土壤中CH4的排放,因此应考虑对其进行预处理以抑制产甲烷活性而不降低稻米生产力。
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