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   

岩溶流域典型农业区水体氢氧同位素的空间异质性及形成机制   总被引：1，自引：0，他引：1  

张金  韩志伟  吴攀  田永著  赵然  罗广飞 《中国农村水利水电》2021,(3)

分别于平水期和枯水期采集了花溪河流域典型农业区地表水和地下水样品。利用氢氧同位素示踪技术,结合土地利用类型对研究区不同水体的补给来源、季节变化及主要影响过程进行了分析,并对不同水体氢氧同位素值进行了空间插值分析,同时对其形成机制进行了分析,阐明了不同土地利用类型影响下的主要水文过程。结果表明:(1)研究区不同水体的主要补给来源为当地大气降水,月亮湖水库受蒸发作用影响明显,地表水和地下水的δD和δ~(18)O整体上呈现平水期高于枯水期的特征。(2)地下水的δD和δ~(18)O在枯水期与平水期均呈现明显的空间分异性特征,西部水田/水库集中区富集,东部旱地集中区贫化,土地利用对研究区环境水文过程影响明显。该研究结果有助于了解不同土地利用方式下地表水对地下水的影响,为流域管理提供科学依据。  相似文献   

基于无人机航摄技术在土地整治项目中的应用研究     

赵彤 《现代农业科技》2019,(21)

针对传统土地整治项目施工监管、后期监测效率不高的问题,本文通过低空无人机航摄和PhotoScan软件后期处理,对比生成的正射影像图和Google earth卫星图的分辨率和位置,发现该影像图能精准、高效的表征项目区影像数据变化,从而得到一种可用于土地整治项目各阶段动态观测的简单、快捷方法。  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   

含刚性沉水植物明渠水流结构的试验研究     

王子建  丁雪  吉庆丰 《灌溉排水学报》2020,(2):78-83

【目的】得到含刚性沉水植物明渠的水流结构。【方法】采用粒子图像测速仪(PIV),用有机玻璃棒模拟刚性植物,在不同来水流量、植物密度条件下对明渠水流结构进行了试验研究。【结果】无植物时平均流速沿垂向呈对数分布规律,有植物时则呈现明显的分区分布特性。无植物时紊动强度值沿垂向变化不大,有植物时在植物顶端位置处紊动最剧烈。流量或植物密度越大,植物顶端位置的流速梯度就越大,植物层上方的流速最大值也越大。植物密度越大,植物顶端位置的紊动强度越大,植物密度对水流紊动强度由最大值减小到最小值的区域影响很大。【结论】刚性沉水植物的存在会改变水流结构,增强紊动掺混,增强流体质点交换和能量传递,且上述影响会随着流量或植物密度的增大而增强。  相似文献   

天敌昆虫低温贮藏研究进展     

沈祖乐  李翌菡  周雅婷  许炜明  邱宝利 《热带作物学报》2017,(2):374-380

在农业生产中由于化学农药的长期不合理使用,导致"3R"问题持续存在和人类赖以生存的环境日益恶化,生物防治产品及技术在有害生物综合治理中的作用越发重要。天敌昆虫的生长发育及存活期往往很短,探索其储存技术是天敌昆虫规模化生产中的关键性环节。低温贮藏可以延长天敌昆虫的寿命,进而可以为生物防治提供充足、稳定的天敌产品。因此,天敌昆虫低温贮藏一直是生物防治领域研究的热点。本文围绕天敌昆虫低温贮藏这一环节,就低温诱导天敌昆虫滞育虫态、冷驯化对昆虫低温贮藏效果的影响、低温贮藏对天敌昆虫适合度(寿命、羽化率、性比、个体尺寸大小、飞行扩散能力等)的影响等方面进行综述,以期为天敌昆虫产品的规模化生产及应用技术提供参考。  相似文献   

长武塬区苹果园和农田相互转换的深层土壤水环境效应   总被引：1，自引：0，他引：1  

刘锦月  韩晓阳  朱元骏 《干旱地区农业研究》2020,38(5):130-135

研究长武塬区苹果园和农田相互转换后0~1 000 cm土壤含水量特征，分析了苹果园土壤干燥化和苹果园转换为农田后土壤水分的恢复效应。结果表明：2、7、17、23、29 a苹果园200~1 000 cm的平均土壤含水量分别为22.8%、21.4%、16.8%、15.4%、14.9%。500~1 000 cm土层中，29 a苹果园平均土壤含水量（14.5%）高于23 a的果园（13.3%）；17~29 a的苹果园均表现为轻度干燥化；基于苹果园和农田转换后土壤水分变化情况估算，苹果园最大种植年限为21 a。苹果园转换为农田1、5、10 a后，农田200~1 000 cm土层土壤含水量分别为：15.3%、15.7%和16.2%，恢复到土壤稳定湿度以上的土层厚度分别为140 cm（1 a）、220 cm（5 a）和400 cm（10 a）。  相似文献   

Soil protection for a sustainable future: options for a soil monitoring network for Ireland          下载免费PDF全文

L. O'Sullivan  F. Bampa  K. Knights  R. E. Creamer 《Soil Use and Management》2017,33(2):346-363

The increased recognition of the importance of soil is reflected in the UN Post‐2015 Development Agenda with sustainable development goals that directly and indirectly relate to soil quality and protection. Despite a lack of legally binding legislation for soil protection, the European Commission remains committed to the objective of soil protection. However, the achievement of a legally binding framework for soil protection relies on the implementation of a soil monitoring network (SMN) that can detect changes to soil quality over time. As beneficiaries do not pay for the provision of soil information, the options for soil monitoring are limited. The use of existing data sets should be considered first. Using Ireland as an example, this research explored the opportunities for a SMN for Ireland considering three existing national data sets. The options for a SMN are considered in terms of their spatial and stratified distribution, the parameters to be measured and an economic analysis of the options proposed. This research finds that for Ireland, either a 10 or a 16 km² grid interval stratified by land use and drainage class offers the best potential in relation to the spatial distribution of existing data sets to reflect local data at a national level. With existing data, the stratified SIS data using the 16 km² grid offers the best value for money, with baseline costs for analysis, excluding field costs, of between €706 481 and €2.8 million. Acknowledging the impossibility of measuring all parameters with ideal frequency, this study proposes a two‐tier system for optimized monitoring frequency. Parameters must anticipate future policy requirements. Finally, the implementation of a SMN must be accompanied by standardized methods, defined thresholds and action mandates to maintain soil quality within allowable limits.  相似文献   

Digital mapping of soil ecosystem services in Scotland using neural networks and relationship modelling—Part 1: Mapping of soil classes     

Matt J. Aitkenhead  Malcolm C. Coull 《Soil Use and Management》2019,35(2):205-216

  相似文献   

Studies on Tomato Seedling Quality Indices Under Simulated Shipping and Storage Conditions     

NING Wei  GE Xiao-guang  LI Tian-lai 《中国农业科学(英文版)》2004,3(12)

Indices of the tomato seedling quality maintenance level after production before field planting were studied through simulated experiments, small--scale operation, indoor analyses and measurements, and field observation. The results showed that under simulated shipping and storage conditions, seedling quality change following different durations (days) of shipping and storage was correlated significantly or even very significantly with certain physiological and morphological indices. With various measured indices following different periods of shipping and storage treatment subjected to multinomial successive regressive correlation analysis, the principal factors influencing seedling quality maintenance level are identified to be chlorophyll content→dry short weight→ leaf freshness index in order of their importance. Significance analysis with multinomial fitted equation indicated that correlations between any one of above three factors and the growth index after field planting reached very significant difference level.  相似文献