海南植胶区土壤有机碳储量的估算

分别采用固定深度法、等效质量法和纵向拟合法对海南植胶区土壤有机碳储量进行了估算。结果表明,海南植胶区4种不同母质分别发育而成的砖红壤土壤有机碳储量均具有明显的垂直分布性,随着土壤深度的增加,有机碳储量逐渐降低。3种方法计算的海南植胶区4种砖红壤0～60 cm土层有机碳储量平均为47.98～59.14 Mg/hm2,远低于同气候带原始森林土壤有机碳储量。     

压力蒸汽热改性橡胶木的物理力学性能分析

为研究介质压力在木材高温热改性过程中的作用,采用压力蒸汽作为传热介质,于155℃/0.4 MPa,170℃/0.4 MPa,170℃/0.8 MPa处理条件对橡胶木进行热改性,测试热改性材的质量损失率、明度、抗弯强度、抗弯弹性模量等指标,探讨不同处理压力和温度改性橡胶木的物理力学性能变化。结果表明,在压强0.4 MPa条件下,155℃和170℃处理的试材,其各项性能可以达到或接近常压条件下更高温度热改性材的性能。介质压强由0.4 MPa增加至0.8 MPa,炭化橡胶木的质量损失率、颜色变化、抗弯强度损失均增大,说明压强越大,热改性程度越剧烈。介质压强对试材的热改性程度有显著影响,提高蒸汽压力可以在较低温度下加快橡胶木的炭化过程,实现木材的高效热改性处理。     

Managing storage pests of maize: Farmers' knowledge,perceptions and practices in western Kenya

Insect pests are a key constraint to effective utilization of cereal crops in sub-Saharan Africa (SSA), with damage caused by these pests in the stores of particular concern. Although a number of approaches have been advanced for control of storage pests of maize, uptake remains a challenge, with effectiveness of some approaches being questionable. We conducted a survey in western Kenya among 330 respondents using face to face interviews and focus group discussions to evaluate farmers' practices, knowledge and perceptions of storage pests of maize, and their current practices in managing such pests as a basis for development of efficient integrated pest management (IPM) approaches for the pests. Majority of the respondents stored maize in traditional granaries, with less than 10% of them using modern improved facilities, mainly due to inability to afford these. Majority of the respondents also cited attack of their stored grains by a number of insect pests, causing about 40% grain losses. The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), sawtoothed grain beetle, Oryzaephilus surinamensis (L) (Coleoptera: Silvanidae), and maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), were perceived as the most common and damaging pests. Farmers' perceptions of pests were positively and significantly influenced by level of education and farming experience, indicating that education and experience build farmers' understanding of storage pests. Storing maize in unshelled form seemed to result in less pest attack, although majority of the respondents stored their maize in shelled form. Moreover, local maize varieties were perceived to be resistant to pests. The farmers applied various control methods, with sun-drying being the most popular practice. Usage of pesticides was minimal, mainly due to high costs, lack of information, and unavailability of appropriate and effective products. There were also other cultural methods applied, such as use of smoke and insecticidal plants. The respondents decried lack of training and extension services on storage pests and their management, underscoring the need to develop extension services. The underlying mechanisms of the perceived pest resistance in local varieties of maize and cultural pest management methods need to be established for exploitation in development of effective IPM approaches. There is also need to address the challenges hindering uptake of modern storage and control approaches.     

环氧化天然橡胶对天然橡胶/白炭黑湿法母炼胶性能的影响

将乳胶状的环氧化天然橡胶(ENR)作为界面改性剂应用于NR/白炭黑的湿法混炼,通过对比ENR改性处理的湿法母炼胶(NES)和未经改性处理的湿法母炼胶(NS),研究ENR对湿法母炼胶性能的影响。结果表明:胶料中的填料-填料网络主要是在硫化初期填料絮凝而形成,通过热处理能够降低NES的填料絮凝速率。与NS相比,不管有没有偶联剂存在,NES均具有更低的絮凝速率常数和由此导致的更弱的填料-填料网络;随着偶联剂用量的增加,胶料的300%定伸应力和耐磨性提高,且NES的提高幅度更大。分析认为,ENR一方面在白炭黑表面形成聚合物层,防止填料的絮凝;另一方面能够与硅烷偶联剂起协同作用改善填料-橡胶界面结合。     

中国橡胶气象研究进展概述

天然橡胶为四大工业原料之一,是极为重要的战略物资。气象条件是橡胶树种植和生长的关键影响因子。针对目前中国有关橡胶气象的研究内容较为丰富但尚未进行系统整理总结的现状,本研究在简要回顾我国天然橡胶种植概况的基础上,从三个方面综述了我国橡胶气象研究进展情况：(1)我国橡胶树引种、种植、生育与温度、水分、光照等气象因子的关系;(2)橡胶寒害、风害及其防御;(3)橡胶气象服务。并据此对橡胶气象研究存在的问题及未来发展方向进行了评述,以期为该领域的研究提供参考。     

气刺微割在PR107上的应用初报

东风分公司自2007年始首先在PR107上推广应用气刺微割采胶技术。由于具有割线短,操作简单,割胶速度快等优点,减轻了割胶工人的割胶劳动强度,成为了提高割胶劳动生产率的有效途径,通过＂以药代线＂达到与常规割改割胶相当的产胶量。     

微生物凝固和酸凝固对天然橡胶性能的影响

通过微生物凝固和酸凝固两种方法制备天然橡胶,对比二者性能的差别。结果表明：微生物凝固天然橡胶的溶胶含量较低,相对分子量大,门尼粘度和塑性初值大,塑性保持率略微低于酸凝固天然橡胶;微生物凝固天然橡胶硫化胶的交联密度高,物理机械性能好。     

橡胶幼龄林下间作菠萝对水上流失的影响

本实验旨在探讨橡胶幼龄林下间作菠萝对水土流失的影响。采用单因素随机区组设计的方法,测定了顺坡种植菠萝,横坡种植菠萝和不间作（对照）条件下的径流量及土壤侵蚀量。结果表明：西双版纳雨季时,5～10月间。横坡和顺坡种植菠萝径流量均低于不问作菠萝,顺坡种植在6～9月间的径流量都高于横坡种植：6～10月间．顺坡种植和横坡种植菠萝能显著降低林间侵蚀量,横坡种植在6～9月间侵蚀量均低于顺坡种植;径流量、侵蚀量和降雨量的变化趋势基本相同;顺坡和横坡种植的总径流和总侵蚀量均显著减少。说明橡胶幼龄林下横坡种植菠萝可以有效减轻林地水土流失。     

天然橡胶生产效率研究述评

主要介绍天然橡胶种植业生产效率的国内外研究进展,并分析现有研究的侧重点及不足。探索天然橡胶生产效率研究的合理思路。     

中国天然橡胶种植业绿色补贴经济分析

中国天然橡胶种植业是需要政府提供补贴的基础产业,如何提高财政补贴的投入效率,什么样的补贴才能更符合WTO相关规定,是补贴政策制订的要点。研究结论表明,中国天然橡胶种植业进行绿色补贴恰能符合此两点要求。