长期定位施有机肥对西北半干旱区土壤酶活性的影响

为了探明长期施用有机肥对旱地土壤酶活性的影响,为旱地土壤改良技术体系的建立提供依据。在宁南旱区进行3a有机肥定位施用试验,设置3个有机肥施用量水平:30 000kg/hm2(L)、60 000kg/hm2(M)和90 000kg/hm2(G),以不施有机肥作为对照(CK)。结果表明,长期施用有机肥对0~20cm土层土壤脲酶、磷酸酶、蔗糖酶影响较为显著,特别是高量有机肥处理,3a较对照平均提高幅度分别为127.7%、26.1%和19.5%;各有机肥处理0~20cm土层土壤脲酶、磷酸酶活性大小顺序基本为G≥ML≥CK,G和M处理效果最显著,3a较对照分别提高(P0.05)32.5%~197.2%和16.7%~34.8%;各有机肥处理过氧化氢酶变化规律不明显,基本维持在8.07~9.48U4。说明,旱地施有机肥对提高一些土壤酶活性有显著效果。     

振动场中圆管流道内聚合物熔体流动的数值模拟

流动和变形是聚合物加工过程中最基本的工艺特征 ,故材料的性质必然同速度、温度、压力、时间等加工参数 ,与加工过程的安排及机械设备密切相关 因此研究聚合物熔体的流变性质不但对加工出优质的制品是不可缺少的一环 ,而且对设计出符合工艺要求的设备也是十分重要的 本文研究了在引入“全程振动场”后 ,对串接于电磁动态挤出机头的圆管模头内聚合物熔体进行了数值模拟 ,在振动场中建立了以Ｏｌｄｒｏｙｄ -Ｍａｘｗｅｌｌ本构方程为主的动态圆管流的数学模型 ,采用了数值差分方法和移动网格法求得了数值解 ,达到对内部熔体流动的了解 ,并…     

大麦黄矮病在甘肃河西地区的流行与生态防治

大麦黄矮病(BYD)在我国华北和西北,特别是甘肃河西地区,是危害小麦、大麦等禾谷类作物的一种重要病毒病。1960年始发于民乐县,以后逐年严重,1964年由王鸣岐和卫润屋等现场考察论证,诊断为大麦黄矮病。随后反复经蚜虫传毒等一系列生物学试验,进一步得到证实。1966年武威县大麦黄矮病大面积流行,使小麦产量损失     

我国大型种业企业要尽快加强企业法律顾问建设

当前对于我国广大种业企业而言,企业法律顾问还是一项崭新角色,企业法律顾问工作,也还是一项崭新的工作.大型种业企业要应对国内外竞争,寻求持续快速稳健发展,笔者认为必须紧跟企业内外形势要求,适时地尽快加强企业法律顾问建设工作.     

会议消息

第二届全国青年作物遗传育种科技工作者学术讨论会拟于1991年4月中旬在北京中国农业科学院召开。年龄在35岁以下、从事作物遗传育种工作的科技工作者均可报名提交论文。论文征集范围:①作物的遗传理论和基础研究;②作物育种方法、技术的研究;     

结论 加强饮食及公共场所

水稻种子发芽前是否进行破休眠处理和采用什么样的破休眠方法 ,对种子发芽影响很大。在国家农作物种子检验规程上谈到几种破休眠的方法。我们几年的试验表明 ,不同品种及不同批次的水稻种子宜采用不同的破休眠方法。1　加热干燥法此方法适用于雨水浸过的种子。 2 0 0 0年水稻收     

Isoflavone,glyphosate, and aminomethylphosphonic acid levels in seeds of glyphosate-treated,glyphosate-resistant soybean

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a hand-weeded control, apparently due to herbicide drift.     

柑桔皮果胶的提取条件研究

以柑桔皮为原料，采用酸法萃取，乙醇沉淀工提取果酸，最佳条件为水料比１０：１，ｐＨ值１．５，萃取温度８５℃，萃取时间９０ｍｉｎ。果胶质量达到食用果胶的国家标准。     

多功能农业是都市农业的方向

<正>发展多功能农业是现代农业发展与进步的一个必然趋势。它的发展不但顺应宏观经济发展的现实,而且捕捉到了大中城市农业发展的切入点,同时也对今后都市农业的发展提出新的要求和挑战。农业的多功能性和多功能性的农业20世纪80年代末90年代初,农业的多功能性最先出现在日本的"稻米文化"中。