塔里木河上游不同林地土壤养分和微生物 以及酶活性变化初探

对塔里木河上游果林地和胡杨林地土壤养分、微生物数量和酶的活性变化进行了研究。结果表明:4种特色果林地的土壤养分、微生物的数量、土壤酶活性均高于胡杨林,而胡杨林的耐盐性最强。5种林地土壤微生物的数量,从4-8月不断上升,8月份达峰值,且以细菌占绝对优势。土壤中脲酶、过氧化氢酶、碱性磷酸酶活性从4-10月逐渐上升,表现为"秋高型",10月达峰值,而转化酶活性则相反,表现为"春高型",峰值出现在4月。土壤微生物数量和土壤酶活性与土壤养分密切相关。     

砒砂岩分布范围界定与类型区划分

 以TM影像为主要信息源,采用“路线调查”和“典型小流域调查”相结合的方法,建立不同类型砒砂岩影像解译标志,在地理信息系统支持下,采用计算机辅助下的人工解译,对以晋陕蒙接壤地区为中心的砒砂岩分布范围进行全面界定,并将其划分为裸露砒砂岩区、盖土砒砂岩区和盖沙砒砂岩区3个类型区,确定每一类型区的分布范围及面积大小。结果表明:砒砂岩区总面积1.67万km2,其中,裸露砒砂岩区面积4543.89km2,盖沙砒砂岩区面积3709.18km2,盖土砒砂岩区面积8432.41km2,分别占砒砂岩区总面积的27.2%、22.2%、50.6%。准确划分砒砂岩区,为其全面治理及黄河粗泥沙来源区治理提供科学依据。     

砂土供磷特性及磷肥效应研究

砂土供磷特性及磷肥效应的研究结果表明，砂土磷素形态以无机磷为主，有机磷甚少，仅占全磷含量的８．８４％。无机磷占９１．１５％，无机磷形态组成以磷酸钙为主，Ｃａ－Ｐ平均为无机磷总量的８６．１％，Ｏ－Ｐ占９．６％，Ａｌ－Ｐ占３％，Ｆｅ－Ｐ占１．３％。各种形态无机磷与速效磷的关系为：ｙ（速效磷）＝４９．３０ｘ１（ＡＬ－Ｐ）＋２１．８５４７ｘ４（Ｃａ－Ｐ）－３．４２０９，表明Ａｌ－Ｐ、Ｃａ－Ｐ对砂土速效磷的     

Microbial and enzymatic properties in response to amelioration of an acidic Ultisol by industrial and agricultural by-products

Purpose

This study aims to evaluate the effects of industrial and agricultural by-products as amendments on soil acidity, soil nutrients, enzymatic and microbial properties, and thus soil quality of an acidic Ultisol under field conditions and to give some index for choosing amendments in acid soils.

Materials and methods

A long-term field experiment was established in an acidic Ultisol in the middle China to investigate the ameliorating effect after application of industrial and agricultural by-products for 4 years. There were five treatments including addition of rice chaff, peanut straw, alkaline slag, alkaline slag with rice chaff, and without amendment of control. Top soil samples (0–15 cm) from individual plots per treatment were collected for the analysis of chemical and microbial properties. The relationships between chemical properties and microbial and enzymatic properties were also analyzed with bivariate correlation analyses and stepwise linear regression.

Results and discussion

Alkaline slag was more effective than rice chaff and peanut straw in correcting soil acidity and induced more increase in catalase activity, acid phosphatase activity, and microbial quotient, and thus more depress in the metabolic quotient, since soil acidity was an important stress factor for microbial and enzyme activities in the Ultisol. Incorporation of rice chaff and peanut straw markedly increased the soil microbial carbon, urease activity, and basal respiration to a greater extent, by more greatly enriching soil with organic carbon and more balanced nutrients of N, P, and K, which were also significant factors affecting microbial properties. Consequently, the application of alkaline slag and rice chaff together was the most effective in enhancing the geometric mean of enzyme activities (an important index of soil quality) when compared with the single application of alkaline slag, rice chaff, or peanut straw.

Conclusions

Soil acidity, organic C, and balanced nutrients of N, P, and K were key factors for affecting soil microbial and enzymatic activities, and thus soil quality in this Ultisol. The combined industrial and agricultural by-products together as amendments would be the better choice to improve soil quality in acidic Ultisols.     

Antiinflammatory activity of Polygala japonica extract

The antiinflammatory activity of the aqueous extract of Polygala japonica (AEPJ) was investigated in mice and rats to find the pharmacological basis for its ethnomedical use. The extract produced a significant inhibition of peritoneal and cutaneous vascular permeability induced by acetic acid and histamine, respectively and ear swelling induced by picryl chloride in mice at the dose of 25.0 mg/kg. Moreover, the extract markedly inhibited footpad edema induced by histamine in rats, and decreased prostaglandin E(2) (PGE(2)) content in carrageenan-induced air-pouch at doses of 12.5 and 6.25 mg/kg respectively.     

基于机器视觉的玉米种粒定向定位摆放装置研制

为实现玉米定向、定位播种,基于图像处理技术研制了一种玉米种粒定向定位摆放装置。在介绍装置的组成和工作原理的基础上,设计了关键部件的结构,通过试验分析和理论计算,确定了关键部件的尺寸参数和安装方位,测试了导向定位管的定位精度,分析了凹型定位槽连续有效作业的条件,并结合作业精度要求,设计了控制方式并设置了控制参数。同时结合金博士郑单958种粒样本的特点,改进了合格种粒胚芽正反面和尖端朝向的图像检测算法。试验结果表明,胚芽正反面检测准确率为98%,尖端朝向检测偏差小于8°,凹槽定位准确率为97%,定位吸取准确率为94%,定位摆放准确率为99%,摆放后角度偏差不大于10°,满足设计要求。该研究可为实现种粒的定向包装以及后续的定向播种提供参考。     

美国兽医协会在执业兽医法律事务中的作用

美国兽医协会作为执业兽医与法律界联系的纽带,积极维护其合法权益。本文分析了美国兽医协会在执业兽医法律事务中,通过主动参与立法、支持司法途径维权、积极进行普法宣传等方式发挥的重要作用。建议中国兽医协会以此为鉴,紧抓全面推进依法治国战略机遇,着力加强基层立法联系点建设,完善多元化纠纷解决机制,开展普法教育与行业自律,以期进一步发挥中国兽医协会在执业兽医法律事务方面的重要作用。     

饲用抗生素主要替代添加剂在养鸡生产中的应用研究进展

随着人们对食品安全的普遍关注和追求,限制甚至禁止抗生素在饲料中的添加已成为必然趋势.为了保证畜禽养殖效益,实现畜禽养殖业可持续发展,研究和使用高效、绿色、安全饲用抗生素替代添加剂,已成为近年来研究的热点.本文对饲用抗生素替代添加剂在养鸡生产中的应用研究进行综述,旨在引导我省养鸡企业及时了解并将科技成果应用于安全优质鸡肉、鸡蛋的生产.     

Suppression of bacterial wilt of tomato by soil amendment with mushroom compost containing <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> IUMC7

Bacillus amyloliquefaciens IUMC7 and its culture supernatant, which we previously found to suppress Fusarium wilt, were found here to have antimicrobial activity against Ralstonia solanacearum. In in vivo experiments, mushroom compost inoculated with IUMC7 significantly reduced disease severity in tomato plants over that in control soils. The R. solanacearum population decreased in soil inoculated with IUMC7. A TLC–bioautography assay showed that one of the antimicrobial substances produced by IUMC7 is likely an iturin-like lipopeptide. These results suggest that these antimicrobial compounds are responsible for disease suppression and that mushroom compost containing IUMC7 has potential as a biocontrol product.