定植密度和施肥种类对蕨菜生长及产量的影响

蕨菜[Ｐｔｅｒｄｉｕｍａｑｕｉｌｉｎｕｍ(Ｌ.)Ｋｕｈｎ]是野生于天然林区的一种蕨科蕨属多年生宿根性草本植物,因其幼嫩茎叶富含多种对人体有益的维生素、胡萝卜素和铁锌等微量元素,自古以来被人们视为山珍采摘食用。近年来,随着人民生活的改善和对外贸易的扩大,蕨菜又成为内销外贸的抢手货,并且需求量不断增加。由此导致了对野生蕨菜连年过量采摘,加之人畜践踏破坏,资源锐减,产量下降,再完全依赖自然生产已越来越不能满足需求。为此,国内外近年开展了有关蕨菜原生地人工驯化栽培工作(齐乐贤,1991;吴会胄等,1994),但蕨菜人工异地栽培的报…     

赴巴西、古巴、墨西哥和泰国糖业考察报告(下)

4　体会和启示　　通过对巴西、古巴、墨西哥和泰国的考察 ,了解到这些国家糖业生产的基本情况和管理体制的特点 ,对广西糖业今后的发展、管理体制改革及产业结构调整很有启发。4.1　蔗糖业是广西的优势产业 ,要坚定不移地发展这一优势产业　　在对四个蔗糖大国的访问期间 ,回过头来看广西 ,广西与几个蔗糖大国 (巴西、印度、澳大利亚、泰国、墨西哥和古巴等 )主蔗区的自然条件和地理区位几乎一样 ,是目前世界上 1 30多个产糖国家和地区中 ,发展糖业自然条件最优越、且为数不多的地区(靠近赤道的热带地区由于无冬季 ,温差小 ,甘蔗糖分比亚热…     

Evaluation of Natural Zeolite as a Material for Permeable Reactive Barrier for Remediation of Zinc-Contaminated Groundwater Based on Column Study

The permeable reactive barrier (PRB) filled with natural zeolite plays the role of a reactive treatment zone for remediation of contaminated groundwater. Based on column lab experiments, the volume of remediated solution, the distribution (K_d) and retardation (R_d) coefficients were evaluated, confirming successful removal and retention of zinc from contaminated groundwater. The effect of hydrodynamic dispersion on zinc capturing by zeolite in PRB was evaluated by the hydrodynamic dispersion coefficient (D_L) and retarded hydrodynamic dispersion coefficient (D_LR) using the Brigham method. For different assumed distances of the barrier, the simulation of one-dimensional zinc concentration profile from the point source through the barrier has been modeled by a simple analytical pulse model. The results show that the flow rate has the most significant effect on the concentration profile, peaks, and broadening of curves. The residence contact time (τ) corresponding to higher K_d and R_d as well as lower D_L and D_LR values outcomes the optimal range of 6.2–9.4 min. This interval corresponds to the experimental performance at the bed length of 8 and 12 cm and flow rate in the range of 6.38–9.57 PV/h. The calculated minimum thickness and longevity confirm the successful application of zeolite as a material in PRB for remediation of zinc contaminated groundwater.     

日光暖棚畜舍的设计及其环境评价

根据不同季节的太阳高度角随地理纬度变化这一原理，确定畜舍塑料暖棚面与地面的最佳夹角，使冬季大寒(最冷)这天正午时分，太阳辐射的入射角与塑料棚面垂直，以其充分利用太阳的辐射热能，提高畜舍内的温度。通过对地处北纬46°霍林郭勒市牧民一户牛舍和一户羊舍的温热环境和舍内空气质量的测定表明，大寒这天舍外气温-24～-10℃下，牛舍内的温度平均8.2℃，羊舍内的温度平均6.1℃，空气质量在卫生要求的范围内，达到了防寒抗灾的目的。     

Just Add Water and Salt: the Optimisation of Petrogenic Hydrocarbon Biodegradation in Soils from Semi-arid Barrow Island, Western Australia

We investigated the potential of soil moisture and nutrient amendments to enhance the biodegradation of oil in the soils from an ecologically unique semi-arid island. This was achieved using a series of controlled laboratory incubations where moisture or nutrient levels were experimentally manipulated. Respired CO₂ increased sharply with moisture amendment reflecting the severe moisture limitation of these porous and semi-arid soils. The greatest levels of CO₂ respiration were generally obtained with a soil pore water saturation of 50?C70%. Biodegradation in these nutrient poor soils was also promoted by the moderate addition of a nitrogen fertiliser. Increased biodegradation was greater at the lowest amendment rate (100 mg N kg^?1 soil) than the higher levels (500 or 1,000 mg N kg^?1 soil), suggesting the higher application rates may introduce N toxicity. Addition of phosphorous alone had little effect, but a combined 500 mg N and 200 mg P kg^?1 soil amendment led to a synergistic increase in CO₂ respiration (3.0×), suggesting P can limit the biodegradation of hydrocarbons following exogenous N amendment.     

冀西北寒旱区旱地莜麦高产栽培措施数学模型及优化方案的研究

采用二次回归正交旋转组合设计,对影响冀西北寒旱区旱地莜麦产量和净产值形成的播量、磷肥、氮肥以及追N比例四项关键农艺措施进行了定量化的综合研究,初步建立了以高产高效为核心的产量函数、净产值函数的数学模型。分析了单因素、二因素产量效应,四项农艺措施对产量的作用的大小依次是N肥>播量>磷肥用量>追N比。高产高效的优化农艺措施是:当每公顷产量≥2250kg时,每公顷播量196～211kg,磷肥74～93kg,N肥112～126kg,追肥占总量的72％～89％。     

椰园/牧草间作:牧草的适应性研究

进行了15种热带牧草在椰园间作的适应性试验,调查了它们的产量情况和生产参数并作统计分析。结果表明:在幼龄椰园内,间作豆科牧草和禾本科牧草,均可获得较高的经济产量;在光照强度大于30％的成龄椰园内,可间作多数禾本科牧草,并能获得一定的经济产量,但不宜间作豆科牧草;在光照强度低于30％的成龄椰园内,不宜于绝大多数牧草问作。间作于幼龄椰园的牧草产值可达1.0~3.0万元/hm2;间作于成龄椰园的禾本科牧草产值可达0.5～2.0万元/hm2。      

赴巴西、古巴、墨西哥和泰国糖业考察报告(上)

介绍巴西、古巴、墨西哥和泰国四国目前的糖业管理体制；分析和对比广西糖业与国外的差距及存在的问题，对广西糖业管理体制改革和产业结构调整提出意见和建议。     

热风与微波干燥胡萝卜的工艺研究

用热风干燥、热风和微波组合干燥对胡萝卜进行干制,检测不同干燥方法对胡萝卜干制品感观品质、复水比、VC含量的影响。结果表明,利用不同的干燥方法所获得的胡萝卜干制品的复水性能和感官品质有明显差异,热风与微波联合干燥胡萝卜制品的品质最优。降低热风温度,缩短热风干燥时间,减小热风速率和微波加热功率,均可提高干制品的复水性、VC含量及其品质。