杨柳毒蛾防治指标的研究

杨毒蛾(Leucoma candida S.)和柳毒蛾(L. salicis L.)是杨树主要的食叶害虫之一。为有效治理该害虫,我们从1984—1987年对杨、柳毒蛾为害杨树的经济阈值,防治指标进行了系统的研究。通过人工模拟摘叶、接虫试验及实际为害损失结果指出,不同林分被害经济阈值不同,存未郁闭林中,胸径年生长量1.5cm以下及2cm以上的人工林,失叶量分别为30％和15％达到为害的经济阈值。在郁闭林分中失叶量25％达到经济阈值。通过饲养了解,平均每头杨毒蛾幼虫一生食叶量为5.3g,柳毒蛾为4.5g。然后采用经验公式计算各林分防治指标。     

ABSTRACT of the Articles Printed in Journal of the Science of Soil and Manure,Japan

Changes in soil moisture determine the reproductive, respiratory, and metabolic activities of soil microorganisms and hence the rate of microbial nitrogen (N) mineralization. Soil moisture also affects the feeding activity and movement of soil invertebrates. Bacterial and fungal grazing by soil invertebrates such as Collembola and nematodes is known to increase N mineralization by increasing the reproductive, respiratory, and metabolic activities of microorganisms. Therefore, to assess the effect of soil moisture on N mineralization, faunal responses need to be considered. We used microcosms to investigate the effect of soil moisture on N mineralization mediated by a species of Collembola, Folsomia candida Willem. We used four moisture levels corresponding to matric potentials of ?42.5, ?11.8, ?0.8, and ?0.5 kPa and investigated the effects of these on Collembola with respect to feeding activity, growth, and contribution to N mineralization. The microbial biomass and ratio of bacterial to fungal biomass tended to increase with increasing soil moisture. Collembola feeding activity and growth increased with increasing soil moisture conditions. Collembola significantly enhanced N mineralization in soil at water potentials of ?11.8 and ?0.5?kPa. The greatest relative increase in N mineralization attributed to Collembola occurred in the ?11.8?kPa treatment. The change in contribution of the Collembola to N mineralization with soil moisture was most likely induced by changes in Collembola feeding activity and microbial community structure. The growth in body length of the Collembola was significantly greater at higher moisture conditions than at the lowest moisture condition, indicating that increases in both metabolic activity and biomass of the Collembola population contributed to the enhanced N mineralization.     

葱莲的同工酶和染色体核型分析

本文报道了对葱莲[Zephyranthes candida(Lindl.)Herb.]的过氧化物酶,酯酶,乙醇脱氢酶和6-磷酸-葡萄糖脱氢酶等同工酶的研究和对葱莲的体细胞染色体数目及其核型所进行的分析。结果表明,葱莲的过氧化物酶同工酶呈现出6条分子量相对较大的谱带;酯酶同工酶可划分成2个活性区,共10条酶带;乙醇脱氢酶同工酶只有1条酶带;6-磷酸-葡萄糖脱氢酶同工酶有4条酶带,可划分成3个活性区。该种核型为2n=28=20m+2m(SAT)+6sm,核型的不对称性为 Stebbins 核型分类的2B 型,具有核型的杂合性。染色体数目为2n=28,与前人报道不一致。     

产朊假丝酵母改善麻疯树提油饼粕营养效价的研究

利用产朊假丝酵母作为发酵菌株,采用固态发酵方式改善麻疯树提油饼粕的营养效价。试验结果表明,控制培养基湿度为100%(w/w)条件下恒温发酵4d,麻疯树提油饼粕中的粗蛋白含量达到最大值。统计分析结果表明,向培养基中添加碳源后,发酵饼粕的粗蛋白增长率、粗蛋白体外消化率、氨基氮含量和蛋白酶活力都比未添加碳源组有显著提高(P<0.05)。与未发酵麻疯树提油饼粕相比,添加10%(w/w)葡萄糖的发酵饼粕中粗蛋白含量、粗蛋白体外消化率和氨基氮含量分别提高了0.48、15.6和37倍,蛋白酶活力达到2100U/g,其营养效价得到明显提高。     

山毛豆对新西兰肉兔的饲用价值

为了改善广西目前象草补精料饲养肉兔这种较低效的饲料结构,试验引进优质豆科牧草新品种山毛豆,并测定其饲用价值。试验采用0、25%、50%、75%和100%的山毛豆分别与100%、75%、50%、25%和0的象草搭配作为肉兔青饲料,饲喂60只肉兔90 d,测定山毛豆营养成分,肉兔采食量、日增重、屠宰性能及经济效益。结果表明:山毛豆初花期粗蛋白达18.29%,优于其他南方常用牧草,全喂山毛豆比对照组平均节省青饲料28.75%,日增重高达(17.47±1.40)g/只;从试验组来看,B组效果最好,因为观察得知其适口性最好,日增重仅次于添加100%山毛豆,为(15.61±1.41)g/只;屠宰率最高为56.38%,经济效益最高,比对照组提高86.87%。综上所述,山毛豆营养价值高,饲喂肉兔效果好,适合在生产上推广应用。     

Mixed tree‐vegetative barrier designs: experiences from project works in northern Vietnam

There has been an increased interest in the use of vegetative barriers in acid‐infertile upland management systems in Southeast Asia. This paper analyses the experimental designs and policies in early‐1990s of using vetiver grass barriers (Vetiveria zizanioides L.) in microwatersheds with short‐rotation tree plantations in Vinh Phu Province, Vietnam. Four different mixed tree‐vetiver models on degraded Ferric‐Plinthic Acrisols are discussed. It is concluded that the institutional approach of demonstrating vetiver barriers as a model had a poor cost‐wise performance, and that the model itself did not address the underlying issues of land degradation due to uncontrolled harvest of organic matter from the forest floors. The institutional approach was tainted with price distortions and ‘disbursement‐oriented’ actions. Alternative and more flexible on‐farm approaches, using V. zizanioides or the indigenous leguminous shrub Tephrosia candida (Roxb.) DC as vegetative barriers, were found to be more cost‐effective and likely to have a higher rate of adoption among farmers. The institutional changes in land allocation policies (securing long‐term usufruct users and transfer rights of agricultural and forest land) that took place in Vietnam in the early 1990s, in combination with a reorientation of programme policies to support needs of individuals and farmers' households, are hypothesized to have contributed more to the ‘regreening’ of the hills, than any single approaches of technical barrier designs by the Swedish‐Vietnamese Forestry Co‐operation Programme (FCP) in northern Vietnam. Copyright © 2002 John Wiley & Sons, Ltd.