Research methods for multistrata agroforestry systems with coffee and cacao: recommendations from two decades of research at CATIE

This paper reviews the research themes and methodologies used by CATIE in agroforestry research with shade trees over coffee (Coffea arabica) and cacao (Theobroma cacao) during the past 20 years. Initially research focused on characterization and production studies (of crop and timber including border areas) of traditional systems using temporary and permanent sample plots on private farms. The assessment area of traditional shade-coffee (or cacao) systems should be the whole plot, including the border areas, and not some subjectively selected central area which supposedly represents unit area productivity. Uncontrolled crop, tree, and management heterogeneity limited extrapolation of early on-farm research results to other farmers' fields. Replicated case studies of best bet technologies (traditional or experimental) on different farms are often preferable to the use of formal experimental designs. On-station research included the use of systematic spacing designs to test extreme shade tree density treatments of coffee. Most nutrient cycling studies were also carried out on-station, using service and timber shade species over coffee and cacao to evaluate the ability of these agroforestry systems to maintain nutrient reserves and diversify production. Plot size (even 36 × 36 m) was limiting for long term research because of inter-plot interference, both below- and above ground, when using fast growing, tall timber trees as shade. These experiences suggest a minimum plot size of 2,500 m². Individual tree designs and tree-crop interface studies (e.g. regression analysis of data taken along transects) are promising experimental/sampling approaches that need further development. The principal research thrusts proposed for the next five years are bio-physical process research on coffee responses to shade and competition with trees (growth, carbon allocation, phenology, disease-pest tolerance, yields and coffee quality effects) and socioeconomic analyses of both traditional and new or improved shade – coffee combinations vs. monocultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

拟合计算林分蓄积量法的研究

本文利用数理统计的方法对常用的树高曲线方程进行拟合选优和检验,以偏差平方和最小者为优,把最优的树高曲线方程代入二元立木材积公式,得出较准确的每木材积的思路,给林分蓄积量的准确计算提供参考。     

马占相思人工实生林立木干形研究

为掌握马占相思人工林立木干形变化的规律性,实测431株样木并采用多个干形指标进行了比较研究.结果表明:实验形数变动系数最小,其变动系数为8.55%;实验形数的调查平均值0.386 8,比目前区内使用的阔叶树数值(0.400 0)呈一定的偏小;正形数系列中,以1/4树高以下变动系数较小,2/10、1/10树高处形数及胸高形数的变动系数分别是8.69%、10.63%、和9.68%;胸高形数、胸高形率以及树高间呈双曲线关系,相关关系紧密.     

胭脂虫实验种群研究

利用人工气候箱,按照正交设计方法,设置了8种不同温度、湿度、光照条件组合,运用生命表技术,对胭脂虫进行了种群动态研究。研究结果表明：15℃以下,胭脂虫卵有少量孵化,但不能完成世代;2D、25、30℃条件下胭脂虫能完成世代。从培育的胭脂虫的怀卵量、种群趋势指数及大小方面比较,以温度25℃、相对湿度60％和80％、光照强度980lx和601x的组合条件为好;胭脂虫的雌雄性比远大于1：1,环境因子对性比具有较大的影响;胭脂虫的种群趋势指数一般大于20,平均约40,对培育十分有利;发育起点温度为9．0℃,世代有效积温为822．9日度;多因素方差分析结果显示,温度为影响胭脂虫发育的最显著因素,而湿度和光照的影响相对较小。     

CO2 fluxes of a Scots pine forest growing in the warm and dry southern upper Rhine plain, SW Germany

The effects of the warm and dry weather in the southern upper Rhine plain in the southwest of Germany on the carbon balance of the Scots pine forest at the permanent forest meteorological experimental site Hartheim were analysed over a 14-month period. The investigation of the net ecosystem exchange of carbon dioxide (F _NEE) of the Scots pine forest started in the extraordinary hot and dry August 2003. Carbon dioxide fluxes were measured continuously using an eddy covariance system and analysed by use of the EDDYSOFT software package. After determining the temperature dependence of the forest ecosystem respiration and the daytime light dependence of the CO₂ exchange, monthly and annual carbon balances of the Scots pine forest were calculated. Mean peak daytime F _NEE rates observed in August and September 2003 (−6.5±3.6 μmol m⁻² s⁻¹) were drastically lower than in August and September 2004 (−11.8±5.2 μmol m⁻² s⁻¹), which did not show pronounced deviations from the mean long-term (1978–2002) climatic conditions. In August 2003, the Hartheim Scots pine forest was a distinct CO₂ source (35 g C m⁻²). The estimates of the annual carbon sink strength of the Scots pine forest ranged between −132 g C m⁻² (August 2003–July 2004) and −211 g C m⁻² (October 2003–September 2004). The main uncertainty in the determination of the carbon balance of the Hartheim Scots pine forest was introduced by the frequently low turbulence levels, i.e. the friction velocity corrected night-time F _NEE fluxes.     

红砂岩地带路基填筑关键技术

红砂岩因其许多不利工程性质在路基填筑中常作弃方处理。本文通过对某高速公路实验段路基填筑的大量实验研究,总结出红砂岩的崩解机理、物理力学性质和路用工程性质,并在此基础上,深入探讨了以“两个处理原则,四大控制指标,一条核心工序”的红砂岩路基填筑关键技术。     

美国黑提葡萄在干热河谷地区引种试验初报

美国黑提葡萄具有粒大、质优、晚熟、耐贮运的特点，在干热河谷地区栽种黑提葡萄，葡萄开花结果提前，成熟早，可以提前上市，抢占市场。华宁县林业局从山东安丘引进美国黑提葡萄在干热河谷地区试验，通过3年的试验证实，美国黑提葡萄适应性强，成熟期提前，品质好，产量高，生物学特性与原产地基本一致，引种试验成功，有较高的推广价值。     

利用植物净化汽车排放污染物的探索研究

针对目前汽车尾气对环境污染日益严重的现象,引出了利用植物对尾气污染物进行净化的方法.然后对国内外对植物与大气污染关系研究的发展动态及研究方法进行了综述和评价.最后参考所述研究方法,提出了利用密闭室法研究植物净化汽车排放污染物的新方法.     

QDG1-30型秸秆枝丫切碎机试验分析

QDG1-30型秸秆枝丫切碎机是我国用于人工林采伐、森林抚育剩余物等木质原料及各种农作物秸秆碎化处理的专用设备,该机采用鼓式切碎装置,结构简单、实用,生产效率高。性能和生产试验的结果显示：与QGP3-30型枝丫切碎机相比,生产率提高了24%以上,作业成本降低了22%以上,具有显著的经济效益。     

锡林郭勒草原遥感植被物候的地面照相验证

利用内蒙古锡林郭勒整个生长季节的草地物候照相观测数据和不同的卫星遥感数据,分析了二者之间的统计关系。结果表明,1)MODIS可见光波段的反射率与地面照相观测的平均亮度值之间呈显著正相关(P0.05),其中,500m空间分辨率的MODIS反射率与地面照相平均亮度值之间的相关性最高,而TM/ETM+反射率与地面照相平均亮度值之间的相关不显著(P0.05);2)MODIS归一化植被指数(NDVI)与地面照相相对绿度指数(G%)之间的正相关明显高于其他植被指数与绿度指数之间的相关性;3)基于遥感与地面照相数据提取的物候发生日期之间的误差大多在7d之内。由此可见,通过地面照相可以客观地评价遥感物候监测的可靠性,这对于选择适宜的遥感数据源和物候监测指标,具有重要的意义。