济南市1997-2014年农业水足迹及结构变化特征分析

为了研究地区农业用水总量与用水结构动态变化响应关系,深化调控农业产业结构与农业用水结构,基于水足迹理论,采用VAR(2)模型建立了脉冲响应函数以及方差分解,研究了济南市1997-2014年农业水足迹变化情况以及农业水足迹构成之间的响应关系.结果表明,济南市农业绿水、蓝水、灰水足迹呈现逐年递增趋势,其中1997-2009年为快速上升阶段,2009-2014年为平稳上升阶段;种植业水足迹与农业水足迹之间不存在黏滞性,渔业水足迹与农业水足迹之间存在负响应关系;影响济南市农业水足迹的重要因素依次为种植业水足迹、畜牧业水足迹、林业水足迹、渔业水足迹.总之,通过适当减少高耗水种植业和畜牧业生产、增加渔业产品产量、制定长期的农业用水规划,并进一步优化农业用水结构,方可实现农业水资源的可持续利用与发展.     

Effects of shade,altitude and management on multiple ecosystem services in coffee agroecosystems

Agroforestry systems provide diverse ecosystem services that contribute to farmer livelihoods and the conservation of natural resources. Despite these known benefits, there is still limited understanding on how shade trees affect the provision of multiple ecosystem services at the same time and the potential trade-offs or synergies among them. To fill this knowledge gap, we quantified four major ecosystem services (regulation of pests and diseases; provisioning of agroforestry products; maintenance of soil fertility; and carbon sequestration) in 69 coffee agroecosystems belonging to smallholder farmers under a range of altitudes (as representative of environmental conditions) and management conditions, in the region of Turrialba, Costa Rica. We first analyzed the individual effects of altitude, types of shade and management intensity and their interactions on the provision of ecosystem services. In order to identify potential trade-offs and synergies, we then analyzed bivariate relationships between different ecosystem services, and between individual ecosystem services and plant biodiversity. We also explored which types of shade provided better levels of ecosystem services. The effectiveness of different types of shade in providing ecosystem services depended on their interactions with altitude and coffee management, with different ecosystem services responding differently to these factors. No trade-offs were found among the different ecosystem services studied or between ecosystem services and biodiversity, suggesting that it is possible to increase the provision of multiple ecosystem services at the same time. Overall, both low and highly diversified coffee agroforestry systems had better ability to provide ecosystem services than coffee monocultures in full sun. Based on our findings, we suggest that coffee agroforestry systems should be designed with diversified, productive shade canopies and managed with a medium intensity of cropping practices, with the aim of ensuring the continued provision of multiple ecosystem services.     

Stability of co‐composted hydrochar and biochar under field conditions in a temperate soil

Hydrothermally converted biomass (hydrochar) is evaluated as a carbon‐rich soil amendment in addition to pyrogenic biochar. After assessing the suitability of hydrochar for use in agriculture, its environmental safety and comparing its chemistry with that of biochar, we describe a field trial established at Halle (Germany) under natural conditions for a temperate climate and without further external management practices. The main objective of our study was to analyse the stability and hence the C sequestration potential of composted chars over a period of 2 years. Four treatments (no amendment control, compost, co‐composted hydrochar and co‐composted biochar) in fourfold field replication were chosen to make a direct comparison of biochar and hydrochar under field conditions. The total organic carbon and total N increased in all treatments in comparison with the control but only in biochar‐amended treatments were N concentrations more stable. Composted biochar showed significantly more black carbon content in topsoil, sampled some months after application, compared with all other treatments. We show that hydrochar is less suitable for long‐term C sequestration in comparison with biochar but has potential for soil amelioration because it delivers essential nutrients. On the other hand, biochar is richer in polyaromatic C than hydrochar and therefore is more stable in the long term. We assessed biochar stability using the black carbon analysis of the different soil samples.     

基于生态足迹理论的新疆可持续发展研究

基于生态足迹和生态承载力理论,对2000-2014年新疆人均生态足迹、人均生态承载力、万元GDP生态足迹、生态协调系数的动态变化进行分析,运用灰色GM(1,1)预测模型预测新疆2020年、2025年人均生态足迹、人均生态承载力、万元GDP生态足迹。结果显示:2000-2014年新疆人均生态足迹呈逐年上升趋势,从2000年的1.699 3hm~2上升到2014年的4.100 5 hm~2,年均增幅为5.86%。新疆人均生态承载力基本保持在1.400 3~1.585 2 hm~2,且有逐年缓慢减小的趋势。人均生态足迹快速增长,人均生态承载力缓慢减小,造成生态赤字逐年扩大,人均赤字额由2000年的0.232 9 hm~2扩大到2014年的2.700 2 hm~2,赤字率由2000年的15.88%上升到2014年的192.82%。资源利用效益水平不断提高,生态协调度不断下降。预测结果表明:2020年新疆人均生态足迹将上升到6.496 4 hm~2,2025年将达到9.586 4 hm~2。2020年人均可利用生态承载力预计下降到1.294 7 hm~2,2025年为1.212 5 hm~2。万元GDP生态足迹2020年下降到0.649 9 hm~2,2025年预计为0.478 0 hm~2。基于此,提出降低化石能源消费比例,控制人口增长,提高土地产出效率是缓解新疆生态赤字的有效途径。     

Reliable data on fine-root turnover from sequential soil coring in an old carbon budget for a 14-year-old Scots pine from the late 1970s: Comments on Majdi et al., Scandinavian Journal of Forest Research 22: 299–303

Abstract

Comprehensive data from different research workers were included in the compilation of a carbon budget for a 14-year-old Scots pine (Pinus sylvestris) in the late 1970s, within the SWECON project (the Swedish Coniferous Forest Project). In a recent paper in the Scandinavian Journal of Forest Research, the authors published a surprisingly high turnover rate of fine roots (7.4 year^?1), maintaining that they had used our old SWECON data from our sequential soil coring. However, a close examination of our original data suggests a turnover of fine-root biomass of 2.3 and for fine-root standing crop (biomass+necromass) of 2.0 year^?1. Supporting evidence is available from other forest sites suggesting that our turnover rates were correctly estimated. Certain errors may exist in different parts of our old carbon budget, e.g. some measurements were carried out for different parts of the tree, while others were attributed to the whole stand. The sequential soil coring technique still remains the best technique available for fine-root growth and turnover estimates in forest stands.     

黄瓜单性结实果实发育与碳氮变化的关系

对黄瓜单性结实品系P 116 8和非单性结实品系UP 3315进行授粉和不授粉处理 ,P 116 8在不授粉的情况下 ,仍具有较好的结实性能 ,其单果质量、果长和果实体积均接近于授粉后生长的果实 ,非单性结实品系UP 3315在不授粉的情况下幼果在花后 3d(天 )就停止发育 ,不能形成产量。随着果实的生长发育 ,果实内碳、氮含量迅速增加 ,花后单果可溶性总糖和蛋白质含量与单果质量呈正相关关系     

不同温度和CO_2体积分数对丰水梨采后生理指标的影响

为明确丰水梨采后适宜的贮藏温度和CO2体积分数,从果实硬度、膜透性、乙醇质量分数、总酚质量分数、PG活性、PPO活性及果心褐变等方面研究了不同温度和CO2体积分数对丰水梨果实的防褐保鲜效果。结果表明,-1.5℃明显降低果实腐烂率,维持较高的果实硬度,但果实发生不同程度冷害;5℃适合短期贮藏(<60d)。与CK相比,3%O2+1%CO2可较好保持果实硬度和风味,明显抑制PPO活性、乙醇产生和果心褐变,延缓酚类物质降解,较好保持细胞膜完整性;2%CO2防褐保鲜效果次之;3%～5%CO2防褐保鲜效果最差。     

猴头菌营养生长最佳条件研究

对4个猴头菌菌株的研究表明,猴头菌营养生长阶段最佳碳源为淀粉,最佳氮源为麦麸及蛋白胨,最适碳氮比为20∶1,最适pH为4.0～5.0,最适温度为25～29℃。     

基于生态足迹分析的可持续发展能力定量评价——以湖南省为例

以区域生产量取代消费量,并用生产性生态足迹作为区域可持续发展的评价指标,对湖南省2004年生产性生态足迹进行计算分析,结果表明,湖南2004年的生物生产发展模式处于一种不可持续的状态,并在此基础上简要分析生态足迹分析法存在的一些缺陷。