Artificial burrow preference by the Japanese crayfish Cambaroides japonicus

SUMMARY: Preference for artificial burrows by the endangered Japanese crayfish species Cambaroides japonicus was studied to improve its cultivation. The occupation of artificial burrows, which were made from straight polyvinyl chloride pipes of different internal diameters ( Y , mm), by crayfishes of different total lengths ( X , mm) was significantly ( P < 0.001, n = 56) described by a linear regression: Y = 0.49 X + 3.42 (19.0 ≤ X ≤ 70.2). Among burrows of different lengths [crayfish total length (TL) × 1, × 2, × 3, and × 4], crayfishes significantly preferred burrows that were greater than TL × 3 ( P < 0.001, n = 588).     

A test for interaction between brown trout (Salmo trutta) and inanga (Galaxias maculatus) in an artificial stream

Abstract –  The interaction between brown trout ( Salmo trutta ; fork length (FL) range 255–390 mm) and inanga ( Galaxias maculatus ; FL range 55–115 mm) was tested during summer through autumn in an artificial stream consisting of a single run-riffle-pool sequence with a natural food supply. Each experimental trial lasted for 15 days, and consisted of two brown trout and 50 inanga collected fresh from a nearby stream, with each species given prior residence in four replicate tests, totalling eight trials in all. In addition, two control trials (each 10 days), with 50 inanga in each, were run. Brown trout almost exclusively occupied the pool, whereas inanga occupied all habitat types, although in different proportions, when tested with and without brown trout. The proportion of inanga in the pool was appreciably lower in the experimental trials with brown trout than in the control trials with no brown trout; prior residence had no significant effect on inanga habitat use. Mortality of inanga attributable to predation by brown trout ranged from 0 to 40% with a mean of 14.5 ± 4.7%. The results suggest that habitat use and survival of inanga populations in small streams can be adversely affected by brown trout.     

西瓜蔓枯病研究 Ⅰ.症状及病原

本文详细报道了西瓜蔓枯病的症状和病原菌的形态特点,并鉴定其有性阶段为Mycosphaerellamelonis(Pass)Chiu et Walker,无性阶段为Ascochyta-cucumis Fautr et Roum.此外,还在其他瓜类作物上作了病原菌的致病性试验.     

香鱼人工育苗技术

根据作者多年来香鱼人工育苗的实践经验，总结了香鱼人工繁殖和苗种培育中关键性的技术。     

利用人工增雨为农田需水服务的信息系统框架

针对我国北方地区水资源严重短缺、农田水分供需矛盾日益尖锐的现状 ,提出了首选人工增雨为农田补水的思路 ,并初步设计了一个利用人工增雨为农田需水服务的农田需水信息系统框架。     

石斑鱼人工育苗技术研究

通过对点带石斑鱼人工育苗生产试验,从饵料准备、环境条件控制、管理措施等方面进行了探索。共培育出规格5～8cm的石斑鱼苗60多万尾。     

奶牛人工授精的优缺点和技术要点

奶牛人工授精技术加速了奶牛品种改良进程,实现了将优秀种公牛精液跨区域、超时限的利用共享,极大地促进了养牛业的发展.以奶牛人工授精应用现状为出发点,介绍了人工授精技术的优点和不足,最后结合自身工作经验,从发情鉴定、适时配种、精液解冻、精液检测、输精、精液保存和妊娠检测等技术要点进行概述,以期更好地促进奶牛人工授精技术的应...     

云水资源的生态和环境功探讨及其应用

为探讨云水资源优化配置的理论依据,文章以二元水循环规律为理论基础,通过对空中水、地表水、土壤水和地下水四水转化的关系和着陆后云水资源存在形式的分析,提出生态和环境功的概念并给出云水资源生态和环境功的计算模型,来描述云水资源的生态环境利用效率。以研究区为例进行应用研究,在雨季末期人工降水20mm时,用此模型计算了研究区三个子区域生态和环境功。应用得到两点主要结论:1)云水资源生态和环境功以地表径流水量生态和环境功为主。2)受水区得到云水资源转化的土壤水和地下水水量受到其初始土壤含水率和初始地下水位限制。应用结果表明云水资源生态和环境功模型函数可以作为云水资源优化配置的理论依据。     

石羊河流域春秋不同播期人工牧草气候生产力分析

2003～2005年对石羊河流域春秋两种播期人工牧草紫花苜蓿(Medicago sative)、沙打旺(Astragalus adsurgens)的生育期,地上、地下生物量,产量等进行了连续测定。结果表明:(1)紫花苜蓿、沙打旺生长第二年(2004年)干物重春播地均高于秋播地。分别增产3 505.0 kg/hm2、2 314.5 kg/hm2。(2)春播和秋播地牧草干物质积累增长关键期均出现在现蕾～开花期。此期紫花苜蓿、沙打旺干物质积累量分别占累积总量的70%和63%。(3)生长第二年(2004年)春播和秋播地青干比最小值出现在开花期,也是牧草刈割的最佳期。(4)春播牧草地下生物量高于秋播。春播紫花苜蓿、沙打旺根干重分别比秋播高2.5～2.6倍和0.5～1.0倍,春播有利于牧草根系生长。(5)春季日平均气温稳定通过5℃为牧草适宜返青温度。在灌溉条件下,牧草干重与热量因子呈显著正相关,生产力高低主要取决于热量的多寡,秋播地和晚熟品种对热量条件的需求更高。     

昆虫人工卵制卵机的研究

本文报道一种结构比较简单的昆虫人工卵制卵机,设计原理与同类其它制卵机不同。用本机制卵,成卵率平均为86％,卵粒外径约564微米,卵壳厚度约17微米。每小时可制人工卵2公斤。用切片石蜡为卵外壳、蛋白质水解物等为内含物制成的人工卵,饲养中华草蛉和大草蛉,成茧率可达97％,与用米蛾卵饲养的结果无明显差异。