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   

严管林慎用钱质为先全面实施好天然林保护工程     

雷加富 《绿色中国(A版)》2001,(12):3-9

天然林保护工程自1998年启动以来,取得明显成效.国家对其投资已累计到位200.7亿元.其主要经验是各级领导重视是组织工程建设的关键;营造良好的社会氛围是工程实施的前提;制定完善规章制度是规范工程管理的保证;探索建立有效的利益机制是工程实施的动力.在今后的发展中应把握保护与发展、保护与经营、保护与稳定、当前利益与长远利益关系、严格工程资金与提高资金使用效益等问题.  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   

古柏赤枯病病原菌的研究   总被引：2，自引：0，他引：2  

雷增普  丛生 《林业科学》1996,32(1):44-49

经Ｋｏｃｈ＇ｓ法则检验证明，ＡｌｔｅｒｎａｒｉａｔｅｎｕｉｓＮｅｅｓ（细链格孢霉）是北京地区古柏赤枯病的病原菌。它引起古柏针叶及嫩梢的大量死亡。２—３年生桧柏及侧柏苗经人工接种证明，该病菌有较强的致病力，它还侵染某些种类的杨树。该病潜育期为５—６天。对病菌生物学特性也作了研究。病原菌生长和孢子萌发最适温度为２５℃Ｆ相对湿度在９０％以上；最适ｐＨ值为６；葡萄糖、淀粉、蛋白胨、谷氨酸为该菌纯培养的优良营养源。  相似文献   

用紫外分光法测定鱼藤中异黄酮类的总含量     

陈欣安  陆磊 《中南林业科技大学学报(自然科学版)》1996,(1)

根据鱼藤中异黄酮类化合物在紫外光２１０～２４５ｎｍ及２９０～３０５ｎｍ处具有吸收峰这一特性，提出了用紫外分光法测定鱼藤中异黄酮类总含量的方法．在３００ｎｍ波长处，浓度低于６×２．６１８×１０－３／ｍｏｌ·Ｌ－１时，测定了标准系列的吸光值，结果表明吸光值与浓度近乎直线相关，相关系数为０．９９７７；标准系列吸光值准确性高；加样回收率达９９％以上；测定样品时，重现性好．  相似文献   

漆树酶在漆酚树脂上的固定化研究   总被引：4，自引：2，他引：2  

雷福厚  郭明高 《林产化学与工业》1996,16(4):19-22

介绍了漆酚树脂吸附金属离子后对漆树酶的固定化方法，比较了Ｆｅ＾３＋和Ａｌ＾３＋、漆酚树脂和漆酚－水杨酸接枝树脂对漆树酶的固定化结果显示，漆酚－水杨酸－Ａｌ螯合树脂对漆树酶的固定化活力最高，测定了溶液ＰＨ，环境温度对固定化漆树酶活性的航固定化漆酶的重作用性。另外，测定了固定化漆树酶的米氏常数，Ｋｍ＝４．９×１０＾－３，并讨论了Ｋｍ小于天然漆树酶的米氏常数的原因。  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