Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau          下载免费PDF全文

J. Cao  Y. Gong  E. T. Yeh  N. M. Holden  J. F. Adamowski  R. C. Deo  M. Liu  J. Zhou  J. Zhang  W. Zhang  S. Zhang  D. Sheng  S. Yang  X. Xu  M. Li  Q. Feng 《Soil Use and Management》2017,33(4):663-671

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.  相似文献   

Differential regulation on C5 expression in goose versus mammals by glucose/palmitate provides a potential protection for goose fatty liver     

Zidi Jin  Long Liu  Cheng Xu  Chunchi Yan  Shuo Li  Tuoyu Geng  Daoqing Gong 《Animal Science Journal》2021,92(1):e13672

Goose fatty liver is a specific type of nonalcoholic fatty liver that is protected from harmful effects associated with severe steatosis. Our previous findings suggest that suppression of the complement C5 may be relevant, but the mechanism is unclear. Therefore, in this study, we first verified the expression pattern of complement genes (including C5) during goose fatty liver formation and then determined the liver fat content and fatty acid composition by high-performance liquid chromatography (HPLC), followed by selecting the differential metabolites to treat HepG2, goose and mouse primary hepatocytes, aiming to explore the mechanism of C5 and inflammation suppression in goose fatty liver. The data confirmed the suppression of complement genes (including C5) in goose fatty livers. Moreover, fat content was significantly higher in fatty liver versus normal ones, with oleic acid and palmitic acid dominantly accounting for the difference. In line with this, high concentration of palmitate led to down regulation of C5 expression in goose primary hepatocytes whereas upregulation in mouse primary hepatocytes and HepG2 cells. In conclusion, regulation on C5 expression by fatty liver related factors including high level of palmitic acid may contribute to the protection of goose liver from severe hepatic steatosis.  相似文献   

L波段低噪声放大器的电路设计与性能分析     

龚宪章 《湖南农业大学学报(自然科学版)》1990,17(1)

闸述了L波段低噪声晶体管放大器中各种降低噪声措施的基本原理,给出了低噪声电路设计的一般原则,以及L波段卫星地面接收系统前端低噪声高频放大器输入级中噪声匹配电路的设计举例.  相似文献   

尖峰岭地区荔枝栽培及区划设想   总被引：1，自引：0，他引：1  

莫锦华 《热带林业》2001,29(1):23-32

尖峰岭地区是我省的主要荔枝产区，有着几十年的栽培历史。近几年荔枝生产得以较大发展，但由于对栽培品种的生产发育与区域分布等问题了解欠缺，栽培品种较杂，没有形成主要生产品种，影响了本区荔枝生产的健康发展。为此特对本地区荔枝栽培作了调研，基本掌握了本区荔枝栽培品种的生长发育表现，对荔枝生产区域化问题有了较深认识，形成了尖峰岭地区荔枝栽培类型及区域布局的初步意见，同时分析了本区当前荔枝生产中存在的主要问题，提出了今后荔枝生产的初步意见和建议，为指导本区荔枝生产提供理论依据。  相似文献   

播量对水稻生长发育及干物质积累的影响     

李忠杰  矫江  王连敏  王春艳  王立志  刘功  焦占力 《北方水稻》2004,(1):18-20

用盆栽方法进行播量对寒地水稻生长发育及干物质积累影响试验,结果表明:稀播的秧苗发根力强、分蘖多、茎基宽、充实度高。播量200g/m2的产量最高。  相似文献   

迷宫螺旋槽的选取研究     

龚林  王春林  施爱平 《农业装备技术》2004,30(3):33-35

以提高迷宫螺旋泵的扬程、流量、效率、汽蚀等性能参数为目标,给出不同使用条件下螺旋槽形状与几何参数的选取。  相似文献   

番荔枝品种选育和栽培生理研究进展   总被引：5，自引：0，他引：5  

刘世彪  杨敬华  谢江辉 《果树学报》2001,18(5):300-304

概述了热带果树番荔枝（Ａｎｎｏｎａ ｓｐｐ．）在选种育种和栽培生理方面的研究进展，包括种质资源，实生树和砧木选种，杂交育种，人工授粉，产期调节以及温度、水分、矿质元素等生态因子对番荔枝生长发育的影响，并就国内番荔枝研究的发展方向进行了探讨。  相似文献   

以花生为主体作物的立体种植高效农业配置     

宫君秋 《中国油料作物学报》1994,(1)

以覆膜花生为优势布局的小麦  相似文献   

乳制品与补锌     

巫庆华  龚广予 《乳业科学与技术》2001,24(1):7-8

目前我国存在一定程度的锌缺乏现象，可以乳制品为载体，有效的增加锌的吸收量。  相似文献   

波尔山羊杂交后代体尺、体重与肉用性能的相关性研究   总被引：1，自引：0，他引：1  

刘铮铸  李祥龙  巩元芳  刘向艳 《猪业科学》2003,20(1):18-21

本文利用 SPSS数据处理软件 (10 .0版 )统计分析了 2 3只 (约 8～ 9月龄 )波尔山羊与唐山奶山羊杂交后代公羊的体尺、体重和肉用性能。结果表明 :(1)波尔山羊与唐山奶山羊杂交 F1 代体尺、体重与肉用性能指标的变异程度大于 F2 代 ,其中宰前重、胴体重、净肉重和胸宽四项指标变异程度在 F1 和 F2 代中都很大 ;(2 )杂交 F1 代、F2 代各项指标 t检验结果 ,除胸宽外其余指标差异显著或极显著 ;(3 )波尔山羊杂交后代中胸宽与各项指标间相关不显著 ,宰前重、胴体重、净肉重与体尺指标相关显著或不显著。  相似文献