集约化猪场臭气产生及调控技术研究

集约化猪场的污染物除了粪、尿以外,还有臭气.本文主要综述了集约化猪场臭气的产生、危害以及消除臭气的各种调控技术,为猪场的生产、环境的净化等提供理论指导.     

设施农业决策系统的数据仓库建设

介绍了数据仓库的主要技术及其在设施农业中的应用和实现方法,以帮助种植者快速得到最优种植工艺。     

稻谷吸湿裂纹生成与扩展的机理分析

当前对KUNZE湿应力模式的分析有两种模式：一种是基于最大拉应力与裂纹形成的高度相关性,一种则是从吸湿裂纹敏感性与谷粒中存在的微裂纹大小的相关性考虑,两种机制各有适用之处。研究了两种裂纹生成机制随吸湿时间的变化规律,并分析了不同热力学条件下垩白对裂纹生成与扩展的影响,结果表明：稻谷吸湿过程的前期,拉应力机制处于主导裂纹生成的地位,吸湿后期,微裂纹机制处于主导地位,两者间存在一个过渡阶段,在过渡阶段,所有影响因素的作用均会被削弱。     

土壤中的抗生素污染及其生态毒性研究进展

越来越多的抗生素被广泛应用于畜牧业和水产养殖业,这些抗生素大部分不能完全被机体吸收,而是以原形或代谢物形式经由粪便排出体外,经不同途径最终进入土壤环境,在土壤中累积造成污染。抗生素污染已成为一种新型土壤污染。为确切评估抗生素在土壤环境中的危害,对该物质在土壤中的污染状况、行为归趋和生态毒性进行了综述,旨在为土壤污染防治和修复提供依据。     

林下套种及坡位和弱光环境对南方红豆杉人工林早期生长及林分分化的影响1）

为高效栽培南方红豆杉人工林,采用方差分析、径阶分布拟合和林木分级等方法,在福建省明溪县进行林下套种及不同坡位和弱光环境的南方红豆杉人工林早期生长及林分分化研究。结果表明：林下套种模式的12年生南方红豆杉林分的胸径、树高、冠幅显著大于迹地更新造林,其胸径、树高、冠幅变异系数较小。10年生林下套种南方红豆杉林分生长有着显著的坡位效应,除下坡与中坡间冠幅无显著差异外,其它均有着显著性差异,3个生长性状生长量和变异系数从大到小依次为下坡、中坡、上坡。在相同林分密度条件下,马尾松林下弱光环境10年生南方红豆杉林分的胸径、树高、冠幅显著大于杉木林下,但马尾松林下弱光环境南方红豆杉的胸径、树高、冠幅变异系数较小。不同培育模式及林下套种时,不同坡位和弱光环境的南方红豆杉人工林径阶分布采用Weibull分布函数拟合,效果较好;林下套种模式及其不同坡位和弱光环境均呈倒J型分布,即其林分结构相对稳定,竞争较合理;而迹地更新造林的林分径阶呈单峰左偏山状分布,表明其处于竞争的自然稀疏后期。南方红豆杉林分林木分级显示,除迹地纯林造林和林下套种的上坡位出现Ⅴ级木外,其它尚未出现Ⅴ级木。因此,营建南方红豆杉人工林应该进行培育模式、坡位和弱光环境选择,其培育模式宜选择林下套种,并在林下套种时优先选择马尾松林下弱光环境和中下坡。     

Assessing yield and yield stability of remnant populations of Cenchrus ciliaris L. in arid Tunisia: developing a blueprint for initiating native seed production

Native seed needs to be sourced locally yet contain ample genetic variation. A blueprint is developed for assembling and assessing native plant material at one eco-geographical site prior to seed multiplication for restoring degraded drylands of North Africa. To satisfy the 'local yet ample' criterion, the feasibility of selecting a limited number of high-yielding genotypes within one starter collection of Cenchrus ciliaris L. in Presaharian Tunisia (100–200 mm annual rainfall) was tested and compared to outcomes with similar work on its ecological complement, Stipa lagascae R. & Sch. Results showed that a limited number of high-yielding genotypes can easily produce quality native seed because of the high genetic diversity of the starter material. Results also showed that there was a high potential to increase the rain-use efficiency of degraded drylands using this seed. Seven ground rules are suggested when building the starter collection: (i) carefully delimit the region for sourcing seed; (ii) work with individual plants; (iii) carefully choose the collection site; (iv) replicate plant material as much as is feasible; (v) match evaluation methods to resource constraints; (vi) wait for conditions of maximum resource availability before culling; and (vii) apply a two-tiered selection strategy.     

Effect of Agronomic Factors on Annual Leguminous Forage Crop in Mediterranean Environments

Dry matter and seed production of five annual leguminous species hairy vetch ( Vicia villosa Roth cv. Orsara) , crimson clover ( Trifolium incarnatum L. ecotype Campano) , squarrosum clover ( T. squarrosum L. ecotype Calabro) , persian clover ( T. resupinatum cv. Accadia) and fenugreek ( Trigonella foenum-graecum L. ecotype Maltese) was estimated in 1989–90 under two density and irrigation rates and with two cutting treatments. The experiments were done at the Forage Crops Institute of Foggia, which has a typical Mediterranean environment. The forage cut severely affected the regrowth of the plants in all species. The year and irrigation factors affect dry matter, seed production and seed yield components more than the plant density rates. The averages over the years, for dry matter and seed yield were 21.0 % and 20.5 % higher in the irrigated than the not irrigated ones. The lower plant density rate, for seed yield trait, gave better result in hairy vetch in irrigated and non-irrigated treatment. Whereas in the other species, the lower rate of planting gave greater yield under non-irrigated and the higher rate under irrigated growing condition. The seed yield components most influenced by irrigation were: thousand seed weight and seeds/pod in hairy vetch and heads/tiller and seeds/head in clovers species. Fenugreek was the earliest forage crop (cut at the beginning of March), followed by crimson and persian clovers (cut at the middle of April) and squarrosum clover and hairy vetch (cut in the middle-late of May). All the cultivars and ecotypes considered not regrowth after cut and could represent an important fresh forage resource for the period March–May for the Mediterranean regions.     

电子皮带秤的安装与调试

电子皮带秤是对散状物料自动地进行连续累计称重的计量设备,对各项技术性能指标要求较高,且时包装运输有特殊要求,拆装限位都要仔细认真,安装调试需要有经验还要有一定的专业知识才能完成.文章介绍了电子皮带秤的结构原理,详细讲述了电子皮带秤的安装方法和具体的调试步骤.     

设施栽培条件下土壤有机质和氮素变化规律研究

对安徽省不同地区有代表性的 5个温室 (塑料大棚 )及其相邻的露地土壤养分的含量和分布进行了研究。结果表明 :①被调查的设施栽培土壤表土有机质、全氮、碱解氮的含量范围依次为 :9.43～ 1 9.72g/kg、1 .0 5～1 .60g/kg、63.54～1 0 1 .67mg/kg;平均值分别为 1 3.94g/kg、1 .30g/kg、85.66mg/kg。②设施土壤有机质、全氮、碱解氮的含量随着剖面层次的加深逐渐降低。③设施栽培更有利于表层土壤氮素的积累。④设施土壤有机质、全氮、碱解氮的含量均高于相应的露地土壤 ,但差异不显著     

旅游环境中空气负离子的研究进展

对空气负离子的基本概念、空气负离子的产生机理与保健医疗作用、旅游环境中空气负离子的评价方法与浓度分布规律的研究进展进行了总结。在此基础上,提出了以空气负离子为核心的生态旅游保健产品和科普产品的开发思路,对未来应重点关注的研究领域进行了分析。表3参31