土壤中掺入不同植物材料对其pH的影响   总被引：6，自引：0，他引：6  

栾书荣  汪晓丽洪岚 封克 《扬州大学学报(农业与生命科学版)》2005,26(3):62-65

在低pH的酸性红壤、近中性的黄棕壤和高pH的盐土中加入茶叶、稻草、大豆3种植物茎叶碎末进行室内培养,研究不同植物材料在短期腐解过程中对不同土壤pH的影响。结果表明：经过14d培养后,茶叶轻微降低红壤和盐土的pH,对黄棕壤的pH没有影响;稻草亦显示出类似的趋势;大豆叶可使酸性红壤和中性黄棕壤的pH有一定程度升高,但使盐土的pH有所下降。  相似文献   

石蛙孵化因子的研究     

朱炳全 《浙江大学学报(农业与生命科学版)》1999,25(6):632-634

通过对石蛙蛙卵孵化因子进行研究,发现水中溶氧量、水温和水质是影响蛙卵孵化的主要因子。石蛙孵化要求:溶氧量大于5 m g/L,水温低于28 ℃,水质无污染。  相似文献   

连续淹水培养条件下土壤氮素的矿化过程   总被引：1，自引：0，他引：1  

李生秀  艾绍英  何华 《西北农林科技大学学报(自然科学版)》1999,27(1):1-5

在淹水条件下,采用每隔一定时间取样分析的连续培养方法,研究了土壤有机氮的矿化过程。试验表明,与间歇淋洗相比,连续培养条件下有机氮矿化过程较慢,矿化累积量较少,且达一定程度后明显降低。但该法在反映不同土壤矿化量高低、不同有机质矿化难易、不同土壤对加入有机物的矿化速率与间歇淋洗法有同样功效;两种培养方法３２ｄ的矿化量也有密切线性关系。  相似文献   

Broodstock spawning and larviculture of whiting (Merlangius merlangus L.) reared in captivity     

Ines Povoa  Andrew Davie  James Treasurer  Hervé Migaud 《Aquaculture Research》2011,42(3):386-398

In recent years, an increasing interest in the farming of marine ‘white’ fish, such as cod, has been observed in the aquaculture industry. One species being considered for aquaculture development is whiting (Merlangius merlangus L.). With little data being available on the domestication of this species, our study aimed to characterize spawning behaviour and rhythmicity in captive broodstock and provide original data on egg incubation, embryonic development and larval rearing. The results observed through video recording showed that spawning mainly occurred at night with active courtship behaviour. Daily egg batches were collected from two separate spawning seasons, with an average fertilization success declining from 77% to 53%. Time to hatch was inversely related to the incubation temperature and occurred after 78 degree‐days (9 days at 8 °C), with emerging larvae ranging in size from 3.3 to 3.46 mm total length and hatch success ranging from 48.3% to 99.9%. In comparison with a clear water environment, a green water regime during the first days of larval rearing significantly improved larval growth and survival. These results are the first to describe spawning activity, early development and larval performances in whiting and are promising for the potential future development of whiting aquaculture.  相似文献   

Predation by invasive signal crayfish on early life stages of European barbel may be limited          下载免费PDF全文

Gordon H. Copp  Lorenzo Vilizzi  William D. Riley 《水产资源保护:海洋与淡水生态系统》2017,27(5):1056-1060

Effects of egg stocking density on egg hatchability,larval quality and water quality for pinfish,Lagodon rhomboides,and pigfish,Orthopristis chrysoptera          下载免费PDF全文

Jason S Broach  Cortney L Ohs  Matthew A DiMaggio 《Aquaculture Research》2017,48(7):3589-3605

Pinfish (Lagodon rhomboides Linnaeus) and pigfish (Orthopristis chrysoptera L.) are relatively new, cultured species commonly used as marine baitfish in the south‐eastern United States and currently have no defined protocols for egg incubation. Thus, experiments were conducted to determine efficient egg stocking densities during static and flow‐through incubation that yielded higher quality larvae. Eggs of each species were incubated statically at 250, 500, 1000 and 2000 eggs L^?1, and after incubation, egg hatching success, larval survival to first feeding, larval morphometrics and water quality were assessed. Stocking densities above 250 eggs L^?1 led to significant reductions in pinfish hatching success and water quality degradation, evident from decreased dissolved oxygen and pH levels and increased nitrogenous wastes. Increased stocking densities for pigfish also resulted in significant water quality degradation, although hatching success was unaffected up to a density of 1000 eggs L^?1. A high flow‐through water exchange rate of 2000% daily resulted in significant reductions in nitrogenous wastes and greater stability in dissolved oxygen and pH levels during incubation when compared to static treatments of the same egg density. Additionally, the high exchange rate of 2000% was critical in maintaining high hatching success and larval survival to first feeding at stocking densities of 1000 eggs L^?1 for pinfish and up to 4000 eggs L^?1 for pigfish. No clear patterns in larval morphometrics were observed among stocking densities. Static incubation densities of 250 and 1000 eggs L^?1 are recommended for pinfish and pigfish, respectively.  相似文献   

锡林河流域温带草原土壤的净氮矿化研究   总被引：6，自引：0，他引：6  

杨小红  董云社  齐玉春  耿元波  刘立新 《农业工程学报》2005,21(12):179-182

氮素矿化是决定土壤供氮能力的重要过程,也是目前国内外研究的热点。该文采用树脂芯方法测定了内蒙古锡林河流域不同温带草原土壤在雨季期间的净氮矿化率,对树脂芯方法在温带草原的应用效果进行了评价。结果表明,实验期间贝加尔针茅草原、羊草草原和大针茅草原土壤的平均日净氮矿化率分别为0.035、0.120和0.125 kg/(hm²·d);树脂芯方法对草原土壤氮转化过程干扰较小,是自然条件下研究温带草原土壤净氮矿化的有效手段。  相似文献   

(鱼免)鱼亲鱼培育及其人工繁殖的研究   总被引：6，自引：0，他引：6  

李明云  郑忠明  竺俊全  徐万土  邬勇  黄福勇  张祖兴  刘伟成 《水产科学》2005,24(9):32-34

采用自然苗培育成的1龄（鱼免）鱼,通过“春肥、夏育、秋繁、冬保”8字方针培育成亲鱼,性成熟率达到95%.经LHRH-A3 0．8～1．8μg／kg催产并放人产卵池自行产卵,获产率达到96．83％。获受精卵650万余粒,受精率达到52％。受精后21．8h孵化出鱼苗,孵化率达到70％。  相似文献   

山女鳟早期发育及低温耐性观察     

王昭明  王炳谦  陈惠 《水产学杂志》2005,18(2):6-10

将发育积温242℃.d的山女鳟发眼卵置山溪中进行流水孵化。在日均水温4.8℃环境下,发育积温达382℃.d时开始有少数鱼苗孵出。此后在日均2.3~1.5℃,最低0.2℃环境下历时36d,发育积温达456℃.d时全部孵化出膜,孵化率90.2%。最早出膜的孵化稚鱼在日均水温1.5~3.7℃,最低0.2℃环境下历时93d,发育积温达668℃.d时开始上浮。受精后172d发育积温达762℃.d时全部上浮,上浮率77.3%。驯饲一个月的稚鱼育成率63.2%。雏鱼孵化及形态机能发育正常,表明山女鳟在日均水温4.8~1.5℃,最低0.2℃的低温环境中可以正常地进行早期发育。  相似文献   

Thermal tolerance of paralarvae of Patagonian red octopus Enteroctopus megalocyathus          下载免费PDF全文

Iker Uriarte  Ana Farías 《Aquaculture Research》2018,49(6):2119-2127

Patagonian red octopus, Enteroctopus megalocyathus, is a merobenthic octopus whose paralarvae have been successfully cultured up to juvenile octopuses. At present, high mortality during the paralarval period prevents the scaling from experimental rearing to commercial aquaculture. The aim of the study was to determine upper (CTMax) and lower (CTMin) thermal tolerance, acclimation response ratio (ARR) and thermal tolerance polygon of paralarvae from different culture conditions and subjected to seven acclimation temperatures (6, 8, 10, 12, 14, 16, 18°C) during the first 5 days of paralarval life. Culture conditions were two types of egg incubation (maternal care and artificial incubators) and two feeding regimes (fed or starved). Fed paralarvae showed thermal preferendum, while unfed paralarvae preferred much higher temperatures than those of acclimation. CTMin and CTMax increased along with the acclimation temperature. Lower values of ARR were obtained in paralarvae from artificial incubation, with this type of paralarva showing the least adaptability to thermal changes. Starved paralarvae showed the lowest values for thermal tolerance range (TTR) and smaller areas of thermal polygon than fed paralarvae. Rearing temperatures above 16°C may be considered suboptimal to paralarvae and affected by the conditions during the embryonic incubation. Rearing temperatures below 8°C may be considered suboptimal for all hatched paralarvae. Therefore, the other temperatures within this range could be used in the context of improving the culture management of paralarvae.  相似文献