土壤团聚体有机碳研究进展   总被引：1，自引：0，他引：1  

朱锟恒  段良霞  李元辰  李振炜 《中国农学通报》2021,37(21):86-90

土壤有机碳是衡量土壤肥力的重要指标,对于促进土壤养分循环、增加养分有效性有重要作用。土壤团聚体是土壤的重要组成部分,是组成土壤结构的最小单元,受到自然因素和人为因素的影响,其形成转化过程与土壤固碳过程息息相关,因而研究团聚体和有机碳的关系及团聚体有机碳影响因素对于土壤结构的改善和土壤质量的提升具有重要意义。本文通过对文献的总结,明晰了土壤团聚体和有机碳的关系,阐述了土壤类型、施肥方式、土地利用和矿区复垦对土壤团聚体有机碳的影响,并从生物质炭的长期定位研究和复垦矿区的土壤修复两方面对土壤团聚体有机碳的研究进行展望,研究结果可为合理的农业生产提供科学依据。  相似文献   

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   

Effects of split feeding on performance,egg quality,and bone strength in brown laying hens in aviary system     

《The Journal of Applied Poultry Research》2018,27(3):401-415

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Fusarium oxysporum对苗期大豆根部的致病性和侵染规律     

韩庆新  辛惠普 《黑龙江八一农垦大学学报》1989,(1):113-119

Fusarium oxysporum对苗期大豆具有较强的致病作用。病原菌自伤口或直接侵入大豆幼苗根部的皮层组织,随着病原菌的侵入和扩展,细胞出现坏死,组织发生崩解,根部组织表现红褐色病斑。环境因素对病原菌的侵染时期和在大豆体内潜育时间的长短有着明显的影响。侵染时期主要受病原菌侵入前自身所处状态和寄主的影响,侵入后潜育时间的长短则受植株状态的影响。土壤环境条件直接影响着病原菌的侵入和寄主的抗病性,间接影响着病原菌在大豆植株体内的扩展和病症的表现。  相似文献   

鸡传染性法氏囊病继发大肠杆菌感染的诊断研究     

路建彪  王允超  孙秋艳  朱瑞良 《畜牧兽医杂志》2005,24(4):8-9

笔者饲养的200多只蛋鸡用种公鸡于50日龄左右突然发病，主要症状为食欲剧减甚至废绝，羽毛逆立，缩颈嗜眠。倒提时口内流出大量黏液状液体，排恶臭白色或微黄带泡沫稀粪，呈水样。发病率达80％，死亡率达32％。剖检可见部分鸡胸肌和腿肌出血，法氏囊水肿出血，个别鸡法氏囊内有黄色较硬的球状分泌物，有的鸡有心包炎和肝周炎，肠道、脾脏和肾脏有出血点。综合以上症状和实验室病毒学和细菌学检测，确诊为传染性法氏囊病继发大肠杆菌感染。  相似文献   

火鸡隐孢子虫在鹌鹑体内发育史的研究   总被引：10，自引：3，他引：7  

查红波  蒋金书 《畜牧兽医学报》1994,25(3):273-278

分离自鹌鹑的火鸡隐孢子虫经口感染２日龄鹌鹑，潜在期为３ｄ，开放期为４－１８ｄ。它在鹌鹑体内发育史过程为：卵巢经口接种后，于十二指肠，空肠，回肠肠腔中子孢子脱囊，至接种后６ｈ全部子孢子脱囊完毕。接种后６ｈ在小肠中出现滋养体。接种后１２ｈ在小肠中出现内含８个裂殖子的裂殖体及裂殖子，接种后４８ｈ滋养体和裂殖体开始出现于直肠。接种后５４ｈ，在小肠，直扬中出现含有１６个子弹形小配子的小配子体。小配子与大配子  相似文献   

美国白蛾生物学特性的研究     

张春玲  李志文  郭爱英 《河北林果研究》1993,(3)

通过对美国白蛾的生活史、生活习性,各龄幼虫的鉴别特征、卵的发育温度、各龄幼虫的耐饥力及蛹重与携卵量关系的观察研究,提出了蛹重与携卵量关系的直线回归模型: Y=-580.07+5704.28x.  相似文献   

基于Hough变换识别单周期正弦曲线图像的算法及实现     

吴志芳 《仲恺农业技术学院学报》2006,19(3):43-46

手工识别成像测井中的裂缝具有一定的主观性，不同的人可能会有不同的解释结果．作者介绍利用Hough变换自动识别裂缝的原理及其算法，并通过实例分析了其应用效果，结果表明，这种算法计算裂缝参数不仅精度可靠，还保证了裂缝参数拾取的唯一性，对实现井壁裂缝参数的完全自动解释有重要意义．  相似文献   

强光下姜叶片的光呼吸及叶黄素循环   总被引：10，自引：1，他引：10  

徐坤  邹琦  关国生 《园艺学报》2002,29(1):47-51

 姜叶片晴天中午的表观量子效率( AQY) 和PSÒ光化学活性(Fv/ Fm) 显著降低, 表明有明显的光抑制现象, 而干旱、高温、强光等逆境条件可显著加重光抑制程度。土壤水分胁迫使光呼吸速率( Pr) 降低, 峰值提前, Pr/ Pn 升高; 同时使叶黄素循环库增大, (A+ Z) / ( V+ A+ Z) 上升, 表明光呼吸和叶黄素循环是姜叶片耗散过剩光能的重要途径。  相似文献   

In vitro growth inhibition effects of rhHGF/cHGF on SMMC-7721 human HCC cell line     

YU Wei-ping  WEI Kai-bin  GAO Lei  SHEN Cheng-xing  ZHANG Rong  WANG Guo-zhen 《园艺学报》2002,18(3):256-258

AIM:To examine the effects of recombinant human hepatocyte growth factor(rhHGF) and native calf HGF(cHGF) on SMMC-7721 human hepatocellular carcinoma(HCC) cell line. METHODS:Human HCC cell line culture, photometric assay, and flow cytometric assay were used in this study .RESULTS:A similar type of dose-dependent cell growth inhibition effect on SMMC-7721 human HCC cells by rhHGF(5-20 μg/L) as well as by cHGF(25-100 mg/L) had been found, with the maximal effect at the highest concentration used. Approximately over 50% of the cells treated with rhHGF(5 μg/L, 10 μg/L, 20 μg/L) accumulated in the quiescent G₀/G₁ phase of the cell cycle over incubation periods for 3 d. CONCLUSION:The growth of SMMC-7721 human HCC cells was strongly inhibited by both rhHGF and cHGF. This might be because the cells exposed to HGF became arrested in the G₀/G₁ phase.  相似文献