水产家族新秀--宝石鲈

宝石鲈(Jewelry perch),又名宝石鱼、宝石斑,属鲈形目丽鱼科.宝石鲈是近2年我国由澳大利亚引进的一个可以人工养殖的优良品种,其原产于澳大利亚的墨水河,被国际养殖界视为极具开发前景的养殖新品种.     

可控止回阀水力特性的测试研究

本文运用水流相似原理，对可控止回阀的流阻系数曲线和动水力矩，进行了系统的水力模型试验研究，为该阀的节能效益和技术开发的可行性，提供了必要的科学依据，其流阻系数值为０．１９，优于液控蝶阀。     

雏鸡蜡状芽孢杆菌中毒的诊断

临夏市城关乡南园村一社某养鸡专业户饲养54日龄狼山雏鸡200只。10日龄时接种鸡新城疫Ⅱ系苗,未发生任何疫情,成活率达95%。1990年3月24日——26日三日内,突然发病,全部死亡.经流行病学、临床症状调查和实验室检查,确诊为蜡状芽孢杆菌(Baciltus cereus)引起的饲料中毒,现报告如下。     

Sediment Load in Runoff Under Laboratory and Field Simulated Rainfall

Soil erosion is one of the most important problems in the Loess Plateau of China affecting sustainable agriculture. Near Luoyang (Henan Province, China), field plots were constructed to measure soil erosion rates under conventional tillage practices using field-simulated rainfall.Field rainfall experiments were carried out to compare previous results from laboratory rainfall simulations on the same soil for interrill conditions. Although in the laboratory experiments, a strong correlation was found betweenthe stream power of the runoff water and the unit sediment load, this sediment transport equation overestimated the field rainfall simulation results. Another sediment transport equation derived by Nearing et al. for rill erosion was in better agreement with the results of the field experiments, although it also overestimated these values. The measured sediment load values during the field rainfall simulations were also lower than those found during field experiments on the same soil but with a loosened surface layer. This difference indicates the importance of soil physical condition of surfce like soil structure and aggregate size, which may contribute to the discrepancy between the field and laboratory experiment results.     

感染反刍动物的几种常见梭状芽孢杆菌

梭状芽孢杆菌属的成员在自然界中是一种非常独特的种类，当其进入到反刍动物体内时，常会引起肌肉和软组织感染、肠道疾病和神经中毒性疾病。梭状芽孢杆菌引起反刍动物发病的机理通常是间接地通过其产生的一种或多种毒素(毒蛋白质)来致病。本文从肌肉和软组织感染、肠道疾病以及神经中毒性感染三个方面探讨了引起感染的梭状芽孢杆菌。     

畜禽的最佳牧草

1．种草喂牛：可选用墨西哥类玉米、紫花苜蓿、苇状羊茅、狼尾草、苏丹草等，不应种植粗纤维含量高的多汁叶类牧草。墨西哥类玉米适宜在年降雨量超过800毫米、无霜期180天以上地区种植，株高1．5米时每月刈割1次。其干物质含粗蛋白质9．5％，粗脂肪2．6％，粗纤维27．3％。茎叶脆嫩多汁，味甜，适口性好，也适宜青贮或调制干草。     

万强加有机添加剂防治番茄肾形肾状线虫试验研究

万强加有机添加剂防治番茄肾形肾状线虫试验研究黎少梅，黄长安（华南农业大学线虫研究室广州５１０６４２）肾形肾状线虫（Ｒｏｔｙｌｅｎｃｈｕｌｕｓｒｅｎｉ－ｆｏｒｍｉｓ）是仅次于根结线央的为害蔬菜的重要病原线虫，该线虫能侵染１００多种植物，其中许多是蔬菜和...