Windbreaks as a pesticide drift mitigation strategy: a review

The use of natural and artificial barriers to mitigate pesticide drift from agricultural and forest applications is discussed. This technique has been considered as an alternative to current methods at a time when environmental concerns are under great public scrutiny. There has been a variety of research experiments on this subject from New Zealand to The Netherlands which have documented reductions in spray drift of up to 80-90%. However, there are still enormous data gaps to utilize this method accurately. The aerodynamic factors of wind barriers and shelter effects on crop growth and yield have been well investigated. In contrast, some of the important aspects of drift mitigation, e.g. porosity and turbulence, have been difficult to obtain and no standard methodologies are currently available to evaluate and classify windbreaks and shelterbelts or to determine their efficiency in reducing drift. Thus there is a significant opportunity to incorporate windbreaks into the tool set of drift mitigation tactics. Government policies, initiatives, legislation, etc, which currently address water quality, BMP, stewardship, buffers, etc, are issues which so far have not included windbreaks as a valuable drift mitigation strategy.     

Water use efficiency and uptake patterns in a runoff agroforestry system in an arid environment

Water is the most limiting factor for plant production in arid to semiarid regions. In order to overcome this limitation surface runoff water can be used to supplement seasonal rainfall. During 1996 we conducted a runoff irrigated agroforestry field trial in the Turkana district of Northern Kenya. The effects of two different Acacia saligna (Labill.) H. Wendl. tree planting densities (2500 and 833 trees per ha), tree pruning (no pruning vs. pruning) and annual intercrops (no intercrop vs. intercrop: Sorghum bicolor (L.) Moench during the first season and Vigna unguiculata (L.) Walp. during the second season) on water use were investigated. The annual crops were also grown as monocrops. Water consumption ranged from 585 to 840 mm during the first season (only treatments including trees). During the second season, which was shorter and the plants relied solely on stored water in the soil profile, water consumption was less than half of that during the first season. Highest water consumptions were found for non-pruned trees at high density and the lowest were found for the annual crops grown as monocrops. Tree pruning decreased water uptake compared to non-pruned trees but soil moisture depletion pattern showed complementarity in water uptake between pruned trees and annual intercrops. The highest values of water use efficiency for an individual treatment were achieved when the pruned trees at high density were intercropped with sorghum (1.59 kg m^–3) and cowpea (1.21 kg m^–3). Intercropping and high tree density increased water use efficiency in our runoff agroforestry trial. We ascribe the observed improvement in water use efficiency to the reduction of unproductive water loss from the bare soil.This revised version was published online in November 2005 with corrections to the Cover Date.     

甜菜苗期鞘翅目害虫诱捕器的制作

介绍了甜菜苗期鞘翅目害虫诱捕器的捕虫原理、制作方法,使用时间、地点等.     

运动捕捉数据结构分析及应用

为了使人们对计算机动画领域的运动捕捉数据有所了解,对三维人体运动捕捉数据结构、骨骼层次关系及数据驱动人体运动的应用进行了详细的分析,最后在人体骨骼模型和操作人员模型的基础上进行了实验,仿真效果良好。     

SPE-GC-μECD测定蔬菜中6种三唑类农药的残留量

[目的]建立一种蔬菜中6种三唑类农药残留的气相色谱检测方法。[方法]蔬菜样品用乙腈提取,盐析分层后上清液经固相萃取柱净化,用丙酮＋正己烷（20＋80）洗脱,采用带微电子捕获检测器的气相色谱仪测定其中腈菌唑、戊菌唑、三唑酮、苯醚甲环唑、丙环唑、三唑醇6种三唑类农药的残留量。[结果]方法的平均加标回收率范围为72．90％-98．80％,相对标准偏差范围为1．18％～9．88％。6种三唑类农药检测限范围为0．010-0．210mg／kg。[结论]该方法的建立为蔬菜中腈菌唑、戊菌唑、三唑酮、苯醚甲环唑、丙环唑、三唑醇6种三唑类农药残留的检测提供了参考。     

船舶柴油机尾气中 PM 颗粒的控制技术研究

根据研究前期内容系统介绍了减少柴油机颗粒物（PM ,particulate matter）排放的后处理技术,从实船应用等方面分析了各处理技术的优缺点,结合研究内容对PM 及其他有害物质的综合处理技术进行了探讨。     

A 15N-Labeling Study of the Capture of Deep Soil Nitrate from Different Plant Systems

The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate （NO3-） to reduce NO3- leaching in a field plot experiment using 15N labelling. The study was conducted on a calcareous alluvial soil on the North China Plains and the plant systems evaluated included alfalfa （Medicago sativa）, American black poplar （Populus nigra） and cocksfoot （Dactylis）. ^15N-labelled N fertilizer was injected to 90 cm depth to determine the recovery of ^15N by the plants. With conventional water and nutrient management, the total recovery of ^15N-labeled NO3--N was 23.4% by alfalfa after two consecutive growth years. The recovery was significantly higher than those by American black poplar （12.3%） and cocksfoot （11.4%）. The highest proportion of soil residual ~SN from the labeled fertilizer N （%Ndff） was detected around 90 cm soil depth at the time of the 1st year harvest and at 110-130 cm soil depth at time of the 2nd year harvest. Soil %Ndff in 0-80 cm depth was significantly higher in the alfalfa treatment than those in all the other treatments. The soil %Ndff below 100 cm depth was much lower in the alfalfa than those in all the other treatments. These results indicated that ^15N leaching losses in the alfalfa treatment were significantly lower than by those in the black poplar and cocksfoot treatments, due to the higher root density located in nitrate labeling zone of soil profile. In conclusion, alfalfa may be used as a plant to capture deep soil NO3- left from previous crops to reduce NO3- leaching in high intensity crop cultivation systems of North China Plain.     

振荡浮子式波浪能转换装置研究

在Froude数相同的情况下，取相似因子为10，对振荡浮子式波浪能转换装置进行了模型设计，并在中国科学院广州能源研究所的造波水槽中对装置做了模型试验，试验在规则正弦波浪作用下进行，实验数据由计算机采集。实验结果显示，振荡浮子式波浪能转换装置具有与常规的振荡水柱式波浪能转换装置相当的俘获宽度比，但其总转换效率较后者高很多，建造成本较低，是一种很有发展前途的波能装置。尽管装置的可靠性有所降低，但在波能密度比较低的区域，如中国，在采取有效保护措施的条件下，装置的性能不受影响。     

长春地区池塘养殖扣蟹的试验研究

１９９４年夏季，作者在长春首次进行扣蟹养殖试验。共投放三期蟹苗２．５ｋｇ，约６０００只。出池时，回捕扣蟹６．４ｋｇ，回捕率为６．１％，扣蟹平均体重为１８．５ｇ／只。文中对养殖扣蟹的投饲，清塘，蟹池建设等问题进行了探讨。     

Foraging pits of the short-beaked echidna (Tachyglossus aculeatus) as small-scale patches in a semi-arid Australian box woodland

Many animals create disturbances on the soil surface while constructing habitat and resting sites, or foraging for food. This soil disturbance, which is sometimes known as biopedturbation, is a major contributor to landscape patchiness in arid and semi-arid environments. In the semi-arid woodlands of eastern Australia, the Short-Beaked Echidna (Tachyglossus aculeatus) creates a mosaic of foraging pits close to the canopies of large trees. The effects of pits on physical, chemical and biological properties of soils were compared at seven sites, each with two levels of disturbance (foraging pit vs. surface) and two canopy locations (under the canopy, in the open) associated with two tree species (Eucalyptus intertexta, Alectryon oleifolius). Foraging pits trapped twice the mass of litter compared with adjacent non-pit surfaces, and there was more litter under the tree canopies than in the open. Pits contained more bark and leaf material, and larger pits tended to trap more litter. Soil electrical conductivity levels were lower in the pits, and although there were greater concentrations of soil nutrients under the canopy, the concentrations of total carbon, nitrogen and sulphur were lower in the pits compared with the surface. Changes in litter mass did not explain differences in soil carbon, nitrogen or phosphorus. Soil in the pit was moister and more porous, and surface temperatures below the litter in the pits about 2 °C lower than at the surface. Respiration was about 30% greater in the pits, and both the early (sorptivity) and late (steady-state infiltration) stages of infiltration were significantly greater in the pits. Soil micro-arthropods were more abundant in the pits, which supported a different complement of taxa, but a similar diversity, to non-pit surfaces. Our results indicate that echidna foraging pits act as substantial resource traps. Given their extensive distribution in semi-arid woodlands, and their marked influence on soil biogeochemistry, echidnas should be seen as important ecosystem engineers in woodland critical for the maintenance of small-scale patchiness and, therefore, the efficient functioning of arid and semi-arid ecosystems.