我国林业小型动力机械发展回顾与现状

林业小型动力机械是生产批量最大的林业机械产品,在林业生产中发挥着重要作用。介绍了林业小型动力机械所包含的产品类型、相关的协会和学会等组织机构及其在国内发展的历史和生产现状;指出了我国产品质量与先进国家之间的差距,以及科研和人才培养等方面存在的不足。     

海南岛油茶资源现状

为了有效保护与高效利用海南岛内现有的油茶资源,于2013年5月至2014年6月选取了海南省15个市县的33个样地的油茶种群及个体进行了调查,分析了海南岛内油茶资源的分布情况、生境状况及形状特征,并就其资源保护、开发与利用的策略和措施提出了几点建议。     

长沙黑麋峰国家森林公园现状分析与发展对策探讨

通过系统地分析与评价黑麋峰近郊型国家森林公园的旅游资源、生态环境质量与开发利用条件,重点从功能分区、发展定位、景观品质提升、形象品牌塑造等方面提出了建设与发展对策,以期为我国城市近郊型森林公园的建设与发展提供借鉴。     

市级土地利用总体规划实施评估研究--以湖南省邵阳市为例

指出了第三轮土地利用总体规划目前已实施7年,随着新情况、新形势的出现,规划也出现了一些不适应性。探讨了土地利用总体规划实施监测评估体系的构建,并提出了相关建议,对规划的继续实施以及对新一轮规划的修编均能提供一定的参考依据。     

社会情境视野下的岭南传统私家园林研究思路

文章通过对社会情境概念进行解析,论述了西方园林史研究范式的变革;针对岭南传统私家园林的研究现状,结合当代国际上的新观点、新动向,探讨了基于社会情境研究园林的构想,旨在为岭南传统私家园林的研究提供新的思路和方法。     

荆门市森防工作现状及对策研究

笔者对荆门市林业有害生物防治的基本情况、机构状况、监测预警、检疫御灾和防治减灾等体系建设作了较全面的介绍,对面临的形势和存在的问题进行了客观分析,并提出了相应的建议,旨在为推进现代林业有害生物防治提供参考.     

Water circulation induced by mechanical aerators in a rectangular vessel for shrimp aquaculture

A water streamer was designed for the purpose of enhancing cost-efficient circulation between the water surface and bottom of shrimp aquaculture ponds. We took direct measurements of the water current field induced by the designed aerator in a large rectangular reservoir of dimensions (L)50 × (W)19 × (D)1.3 m³ and compared the results with those of a standard Taiwanese paddle-wheel aerator. Vertical circulation between the surface and the bottom induced by the paddle wheel aerator was less than that by the designed aerator. Furthermore, the paddle-wheel aerator consumed more electric power than the designed aerator. The structures of water current induced by the two aerators are elucidated, and the advantages and disadvantages of the aerators are discussed.Auxiliary employment of the designed aerators may contribute to delivery of high DO water throughout the pond, which is more efficient than a paddle wheel aerator.     

Dual effects of reversed winter–spring temperatures on year‐to‐year variation in the recruitment of chub mackerel (Scomber japonicus)

To clarify the effects of temperature on the recruitment of chub mackerel (Scomber japonicus) in the North Pacific, we investigated the influence of winter surface temperature (WST) on spawners at the time of maturity around the spawning grounds and the influence of ambient spring temperature on larvae using estimated temperature (ET) obtained from particle tracking experiments. We found a significant positive correlation between ET approximately 10 days following hatching and the recruitment per spawning stock biomass (RPS) after 2000. The closer (more meandering) the Kuroshio Current (KC) axis was in relation to the spawning ground, the higher (lower) the spring surface temperature and the higher (lower) RPS was in the spawning ground. In contrast, WST inside KC near the maturity/spawning ground was significantly negatively correlated with RPS. A significant negative correlation between the temperatures in winter and spring was detected in the area after 2000, when the conditions of the Pacific decadal oscillation index and the stability of the Kuroshio Extension were synchronous, indicating that KC shifted northward during this time. The reversed temperature pattern was consistent with the winter–spring movement of KC axis in the offshore direction and was correlated with the winter–spring difference in the intensity of the Aleutian low. These results suggest that the annual variation in chub mackerel recruitment after 2000 was strongly affected by the combined effects of ambient temperature because of the reversal of conditions that occurred between winter and spring around the maturity/spawning ground, which was related to the KC path.     

我国坡耕地农业机械化发展现状

随着经济的发展,用于农业用途的平耕地逐渐减少,为保证粮食出产总量,必须寻找未开发或开发程度低的耕地,坡耕地即为这种耕地。坡耕地分布在开阔地区,也有分布在丘陵山区,本文通过分析各个地区的农机使用情况,论述坡耕地农业机械化发展现状,旨在为发展坡耕地农机化提供参考。     

宁夏马铃薯脱毒种薯产业的发展现状及对策

为宁夏自治区马铃薯种薯产业的发展提供理论依据和实践参考,介绍了宁夏马铃薯脱毒种薯产业的发展现状,详细分析了该产业在不断发展的过程中出现的主要问题,并提出了相应的对策措施。