土槽模拟开沟覆膜滴灌技术下盐分调控规律

新疆气候干旱与土壤盐碱化并存,是制约新疆农业发展的主要因素,开沟覆膜滴灌技术综合了膜下滴灌技术与开沟技术的优点,理论上可有效治理盐碱地。在开沟覆膜滴灌技术下,设置不同灌水定额与灌水次数,利用试验土槽模拟盐分调控规律,结果表明:1第1次合适灌水定额对盐分的淋洗起主要作用,可使土体盐分达到较稳定的状态,盐分也随水分侧向运移,并在土埂表层聚集;2灌水定额的增加促进盐分随水分向远离滴头和向深层方向运移,使得覆膜间、覆膜边盐分淋洗的深度增加,脱盐区增加;3在灌水定额为300m3/hm2时,可以在滴灌带横向0~23cm,下部58cm处迅速形成一个含盐量小于1.5%的达标脱盐区,满足当地作物正常出苗,故建议当地可选择300m3/hm2作为第1次灌水洗盐定额。     

秦巴山区土壤信息系统的建设研究

棵间土壤蒸发是塔克拉玛干沙漠公路防护林耗水的重要组成部分。应用Micro-Lysimeters测定了1个灌溉周期内咸水滴灌下距林木不同位置处的土壤蒸发量。分析了土壤蒸发与水面蒸发的关系,通过一维平差处理对防护林土壤蒸发量进行了估算。结果表明,塔里木沙漠公路防护林棵间土壤蒸发具有明显的季节变化特征。试验初期棵间土壤蒸发量:根基部>距根基50cm处>距根基100cm处;第5d以后,根基50cm处>根基部>距根基100cm处。林地土壤蒸发随土壤含水量的减低呈整体下降趋势。通过估算,咸水滴灌下整个防护林年土壤蒸发总量为2.63×106 m3,占总灌水量的21.43%,生长季蒸发量占全年蒸发量的92.28%。     

Bottlenose dolphins (Tursiops truncatus) in the north-western Adriatic Sea: Spatial distribution and effects of trawling

1. Many species and populations of odontocetes have modified their behaviour to take advantage of feeding opportunities provided by fishing activities, with depredation of fishing gear being the most common type of adaptation.
2. The northern Adriatic Sea has been identified as an important marine mammal area because of a regular occurrence of common bottlenose dolphins. Boat surveys were conducted within a 3,000 km² sector of the Adriatic Sea off the coast of Veneto, Italy, between April and October 2018–2019. Based on 76 days at sea, 10,711 km of navigation, and 81 h 26 min of dolphin tracking, this study contributes novel quantitative information on dolphin spatial distribution, and on their occurrence in the wake of beam trawlers, otter trawlers, and midwater pair trawlers.
3. A combined generalized additive model and generalized estimation equation framework indicated that trawling—along with other physiographic, biological and anthropogenic variables—influenced dolphin distribution. In days of trawling, the chance of encountering dolphins increased by ~4.5 times (95% confidence interval 1.8–11.0) near active beam trawlers, by ~16.0 times (7.1–36.0) near otter trawlers, and by ~28.9 times (12.0–69.6) near midwater pair trawlers.
4. Spatial modelling was used to create maps of predicted distribution, suggesting differences in habitat use between trawling and no-trawling days. Spatial modelling for all days identified a dolphin distribution hotspot of 832 km², situated off the Po river delta.
5. Evidence contributed by this study can be used to inform management action within one of the world's areas most heavily impacted by fishing and other human encroachment. Such management action would help enforce the European Union's Habitats Directive and Marine Strategy Framework Directive, while also informing EU's Maritime Spatial Planning.

     

Contributions of marine infrastructures to marine planning and protected area networking

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中国海洋一般中上层经济鱼类生物学研究的回顾与前瞻

中国海洋一般中上层经济鱼类种类繁多,大多为r选择型或由K选择型演变为r选择型,资源更新速度较快、可持续利用的前景较为广阔,在中国海洋捕捞业产量中的比重呈上升趋势。本文综述了中国海洋一般中上层经济鱼类的渔业发展概况,着重介绍了鳓(Ilisha elongata)、灰鲳(Pampus cinereus)、竹鱼(Trachurus japonicus)、金色小沙丁鱼(Sardinella aurita)、黄海鲱(Clupea harengus pallasi)和黄鲫(Setipinna taty)等6种主要种类资源生物学的研究进展,概述了这些种类的种群鉴别和划分、洄游分布、越冬场、产卵场及其产卵期、年龄和生长、摄食习性、生殖力和群体结构变动,以及其资源量和可捕量的评估,同时展望了其资源生物学研究的前景并提出了前瞻性建议。