Interacting effects of yak dung deposition and litter quality on litter mass loss and nitrogen dynamics in Tibetan alpine grassland

The effects of grazing‐induced dung deposition on plant growth and soil attributes are well established, but little is known about dung effects on litter decomposition. Here, we tested effects of yak dung on litter decomposition and nutrient content in a Tibetan alpine meadow. We incubated litter of four common alpine meadow species using litter bags in the field. Two low‐quality species (Kobresia capillifolia and Elymus nutans) with low nitrogen (N), high C/N and Lignin/N, and two high‐quality species, (Saussurea nigrescens and Thermopsis lanceolata) were incubated in monoculture with and without dung addition. Mass loss of leaf litter, fibre fraction (cellulose, hemi‐cellulose and lignin), N and phosphorus (P) were measured after 6, 12 and 18 months of incubation in the field. Dung addition significantly increased decomposition constants for low‐quality litter species, but not for high‐quality litter species. Dung addition promoted cellulose and hemi‐cellulose loss, but lignin loss was not affected by dung addition, except after 12 months for high‐quality litter species. Dung reduced N immobilization after 6 months and did not affect subsequent release in low‐quality litter species, and promoted N release after 6 and 12 months in high‐quality litter species. Regardless of litter quality, dung increased P release after 6 and 12 months. Our results suggest grazing‐induced dung deposition may accelerate C and nutrient turnover, primarily through increasing the mass loss of low‐quality litter, P release from litter and N release from high‐quality litter. The mechanisms underlying the effects of dung deposition need to be clarified in future studies.     

秸秆生物反应堆对设施土壤环境特性的影响

[目的]研究秸秆生物反应堆、秸秆生物反应堆与牛粪配套措施对土壤理化性质、微生物量、酶活性及作物产量的影响。[方法]试验以常规栽培为对照(CK),研究秸秆生物反应堆(BSBR)、秸秆生物反应堆+牛粪(BSBR+CM)对土壤理化性质和微生物的影响。[结果]与CK相比,秸秆生物反应堆能显著提高土壤含水率,有效降低土壤碱性和EC值,显著增加土壤有效氮、有效磷、有效钾含量,为微生物活动提供充足的氮源,促进微生物碳氮增加以及蔗糖酶与脲酶的活性,显著增加番茄产量,配施牛粪效果更明显;BSBR+CM处理显著提升了土壤有机质含量。[结论]综合考虑认为,内置式秸秆生物反应堆配施牛粪,可以调整合理的碳氮比,对温室土壤连作以及盐渍化具有一定的修复作用,起到增产的效果,是一种较为合理的农艺措施,建议推广应用。     

貂粪沼气发酵产气潜力研究

[目的]研究不同料液比对貂粪沼气发酵产气效果的影响,为以貂粪为原料进行沼气发酵及貂粪的多样化处理提供参考。[方法]以貂粪为原料,沼液为接种物,35℃恒温厌氧发酵,比较不同料液比对貂粪产气效果的影响。[结果]试验表明,发酵料液配比为1∶2时,貂粪更易降解,产气量高。试验初步确定貂粪发酵的水力滞留时间为21 d。料液总固体(TS)浓度为6.0%时,貂粪的产气潜力为345.7 mL/g TS,350.3 mL/g挥发性固体(VS)。[结论]貂粪是一种无需调碳氮比且产沼气潜力很高的发酵原料。     

发酵牛粪作为奶牛卧床垫料的微生物消长规律研究

为了研究发酵牛粪作为奶牛卧床垫料的微生物消长规律,本试验选择舍饲散栏泌乳牛舍,检测1个自然年度牛粪垫料不同深度的微生物(细菌和真菌)数量。每2月检测1次,每次连续7d。结果表明,不同月份牛粪垫料的表、中、深层细菌数量随填铺卧床时间的增长表现出上升趋势,刚填铺的牛粪垫料细菌数量为2.0×10~6~3.8×10~7 cfu/g,填铺7d时细菌数量达4.7×10~7~3.6×10~8 cfu/g,4、6、8和10月份牛粪垫料的细菌数量均表现为表层偏高、中层偏低的趋势;牛粪垫料中真菌数量没有表现出明显的消长规律,且填铺7d时真菌数量增长幅度较小,刚填铺时牛粪的真菌数量介于4.3×10~2~1.5×10~3 cfu/g,填铺7d时真菌数量为9.5×10~2~4.8×10~3 cfu/g。此外,牛粪垫料的细菌和真菌数量与环境温度间均不存在显著相关性(P0.05)。该研究可为奶牛卧床消毒制度的完善提供可靠数据,以提高奶牛的生产性能和健康水平。     

黄粉虫虫沙与微生物功能菌复合添加对罗马生菜营养品质的影响

[目的]研究了黄粉虫养殖过程中产生的废弃虫粪与微生物功能菌复合添加对罗马生菜营养品质的影响,为配制新型生物有机肥料提供理论依据。[方法]以国产复合肥(T_1),进口复合肥(T_2),精制茶粕有机肥(T_3),生物有机肥(T_4),黄粉虫虫沙与微生物功能菌复合(T_5),黄粉虫虫沙、精制有机肥与微生物功能菌复合(T_6)组成的6个不同处理为肥料来源,进行罗马生菜的盆栽试验。研究了不同处理对生菜营养品质的影响。[结果]T_5处理生菜的总蛋白含量较高,而总酸、总糖、维生素C含量与其他处理无显著差异。[结论]以黄粉虫虫沙与微生物功能菌复合形成的生物有机肥料对生菜营养品质的提高有促进作用。     

利用改进BP神经网络预测初产奶牛产奶量的方法

针对传统BP算法的缺陷，提出了一种采用L-M训练法的BP神经网络。在此基础上建立了基于改进BP神经网络非线性系统的奶牛305d产奶量预测模型，此模型可以提前215d预测初产奶牛305d产奶量，从而实现提早进行选择，加速奶牛育种工作进程。并通过具体的实验验证了改进BP神经网络预测模型的有效性。