根土空间对花生生长发育和产量的影响

为明确花生生长过程中是否存在生长冗余,探讨花生高产的适宜生长度,以高产花生品种青花7号为试材,设长×宽×深分别为40 cm×20 cm×20 cm、40 cm×20 cm×40 cm、40 cm×20 cm×60 cm、40 cm×20 cm×80 cm4种规格不等的根土空间,采用网袋法,研究了根系生长空间对花生生长发育和产量的影响。结果表明,随着根土空间增大,株高逐渐增高,分枝数逐渐增多,根系干质量和茎叶干质量逐渐增大,其生育进程的推进差异越来越大。根土空间过小显著影响各时间段花生开花数、下针和结果;根土空间过大则中前期开花数、下针和结果少,中后期开花数、下针和结果多;适当的根土空间(如限根深度60 cm)则中前期开花数、下针和结果多,中后期开花数、下针少。说明根土空间过小影响产量提高的主要原因是生长量不足,而根土空间过大影响产量提高的主要原因是冗余生长。适当空间则既能保证足够的生长量,产生的冗余生长又少,从而提高荚果产量和籽仁产量,为花生高产新品种的选育和栽培提供理论依据。     

地下公共空间的功能和导向研究——淮安市市中心地下广场改造

研究地下公共空间的功能和导向,并以此为根据,从入口、交通流线、光线、商业性质4个方面对淮安市地下中心广场进行设计和改造。     

基于关联数据的农业信息空间数据组织研究

介绍了农业信息空间、关联数据和RDF格式的内涵与应用研究现状,以及农业信息空间下基于关联数据的知识资源组织方式和机制原理,提出了基于关联数据的知识资源发布应用模式和资源服务方式,有利于更好地扩展知识资源的内容,提升知识资源的发现服务,为我国关联数据的理论研究和应用实践提供一定的参考。     

水稻持久抗瘟性研究

以病区时空动态效应强度检验为核心,以纬度病圃、抗谱测定和抗性信息流的追踪考证作为持久抗瘟性鉴定评价方法的基础。经综合评价,认为特特勃(Tetep)、小粒野生稻Oryzaminuta J.S.Presl ex C.B.Presl、湘资3150、天津野生稻、谷梅二号、魔王谷等具有持久抗瘟性,可作抗源用,其中小粒野生稻兼具持久抗褐飞虱Nilaparvata lugens St(?)l性能;提出了持久抗瘟性鉴定的原则和方法。对持久抗瘟性的时空动态特性、广谱抗性与持久抗性的关系等进行了讨论。     

内蒙古黄河上中游天然林资源保护工程区立地条件分析

文章通过对自治区黄河上中游“天保”工程区的自然条件分析和立地类型划分 ,提出了恢复植被 ,控制水土流失 ,减轻风沙危害的具体措施。根据工程区不同的立地类型 ,采取乔、灌、草相结合的不同模式 ,最大限度的增加植被盖度 ,从而达到改善生态环境的目的。     

Restoration and stress relief through physical activities in forests and parks

A field survey assessed the restorative effects of visiting an urban forest and a city park in Zurich, Switzerland. Respondents rated their headaches, level of stress, and how balanced they felt both prior to visiting the outdoor location and at the time of being interviewed. Suffering from headaches and stress decreased significantly, and feeling well-balanced increased significantly. The recovery ratio for stress was 87%, and the reduction in headaches was 52%, in terms of the possible improvements on five-point rating scales. With respect to feeling well-balanced, the observed changes amounted to 40% of the possible enhancement. Positive effects increased with length of visit, and individuals practising sports (e.g., jogging, biking, playing ball) showed significantly higher improvements than those engaged in less strenuous activities (e.g., taking a walk or relaxing). These findings support previous research on how exercise in green spaces promotes well-being and recovery from stress.     

Development of a spot plow providing complete inversion for effective weed control

Tillage for the "complete inversion" of soil, that is, overturning soil slices 180° was proposed, a "spot plow" was developed and tested to accomplish the task, and a simulation model was evaluated to demonstrate the efficacy of the plow on weed control. A 360 mm wide spot plow was designed to operate at a speed of 1.9 m s⁻¹ for the spot plowing with the least possible lateral displacement of the soil slice by utilizing the inertia of the soil slice and securely rotating it. In field experiments, complete spot inversion required an operating speed of at least 1.6 m s⁻¹; at lower speeds, a portion of the soil block was left half-inverted and further lowering led to considerable lateral displacement. The displacement in the forward and lateral directions was minimal, implying that spot plowing is suitable for potential application to and verification of the weed population dynamics model in the field. A simple linear matrix model of the population dynamics of annual weeds was proposed, whereby four layers of soil were set to describe tillage and other ecological events. The effect of tillage on weed control was evaluated by the equilibrium reproduction rate allowed to sustain a stable population of weeds. The simulation model showed that alternately changing the depth of spot plowing had a significant effect on controlling weeds of low-survival-rate seeds, even when some incomplete inversion of the soil slice was taken into account.     

Spatial and temporal variability of air temperature across urban neighborhoods with varying amounts of tree canopy

Recent studies have emphasized the presence of microclimates in urban settings, but most do not have the high resolution observations necessary to understand the interactions taking place at a neighborhood scale. This study used a network of 10 identical weather stations and high resolution land cover data in Knoxville, Tennessee, to analyze the microclimates of a medium-sized city with a temperate climate. Two stations were installed in each of four urban neighborhoods in locations with varying localized tree cover, and two additional stations were installed in the center of downtown and in a nearby urban nature center. The intra-neighborhood results suggested that there is significant temperature variability within a single neighborhood based on the tree canopy density immediately surrounding a given weather station. However, the inter-neighborhood variability (differences between neighborhoods) was similar in magnitude, which suggests that the overall differences in neighborhood characteristics also have an effect on climate. Land cover at the neighborhood scale (in particular tree canopy percentages at the 500-m radii) had the highest correlation with the minimum daily temperature (Tmin) during the summer season. Maximum daily temperature (Tmax) relied most on the distance of each station from Downtown and the amount of impervious area in the 50 m surrounding each station. Tmax was also most influenced by surrounding land cover during dry conditions (a Dry Moderate air mass). Overall, highly localized impervious land cover percentages and larger-scale forested canopy were important in explaining temperature fluctuation, pointing to the importance of scale in microclimate assessments. Dry air masses enhanced the relationship between land cover and temperature during the day, while moist air masses did the same overnight. These data can be used to better inform planning strategies to build resiliency to extreme heat into urban environments by considering the influence of tree canopy.     

成套小样园作为典型众数抽样调查单元的方法

本文介绍了用成套小样园作为典型众数抽样调查单元的方法测定两个不同林分小班的蓄积，并与用点抽样和不同形状样地的系统抽样结果相比较，表明用成套小样园作为典型众数抽样调查单元的方法能满足９０％以上的精度，而且工效很高；作者也探讨了使用此法的条件．     

新疆国际旅游客源市场研究

新疆具有明显的旅游资源优势,是中国很有吸引力和巨大潜力的旅游地区。特别是近年来,国际旅游发展较快。因此,对其国际旅游客源市场结构进行研究,有利于进行明确的国际客源市场定位,制定切实可行的客源市场开拓策略,进一步加快国际旅游的发展。本文在分析大量数据的基础上,利用了年际变化强度指数和地理集中指数对新疆国际旅游客源市场的时间结构、空间分布结构进行了分析,然后利用SPSS统计软件建立了新疆国际旅游客源市场的线性回归预测模型,并提出了今后新疆国际旅游客源市场的开拓对策,为新疆国际旅游业的发展提出了一些设想。