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2017-2019年调查了辽宁春玉米产区不同秸秆还田模式对玉米主要病害发生为害的影响,结果表明:与传统不还田旋耕栽培模式相比,秸秆覆盖还田后玉米主要病害的发生为害最重,茎腐病发病率增加68.77%,穗腐病发病率增加20.01%,大斑病病情指数增加39.54%;秸秆碎混旋耕还田后茎腐病发病率增加48.20%,大斑病病情指数增加16.84%;秸秆田外堆置腐解后深翻还田可有效降低玉米茎腐病和穗腐病等土传病害的发生,茎腐病发病率降低41.66%,穗腐病发病率降低30.00%;秸秆还田配套不同耕作栽培模式对玉米主要病害发生为害有一定的叠加影响,免耕栽培会加剧病害发生,而深翻栽培可降低病害发生。由此可见,秸秆直接还田,特别是覆盖还田会加重玉米主要病害的发生为害,而秸秆经充分腐解处理后再还田能有效降低玉米主要病害,尤其茎腐病和穗腐病等土传病害的发生。 相似文献
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蔬菜水培营养液电导率EC值与其配方浓度剂量成直线相关,通过测定电导率,运用回归方程可求得该营养液浓度剂量和调整补充营养液的量。 相似文献
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为探明黄曲霉毒素B1(AFB1)对雏鸡细胞免疫功能的影响,将100只1日龄艾维茵健康公雏鸡随机分为4组,分别喂以基础日粮(玉米–豆粕型基础日粮,对照)和AFB1日粮(基础日粮中AFB1的添加量分别为0.15、0.3、0.6 mg/kg,分别记为AFB1Ⅰ、Ⅱ、Ⅲ组),试验期21 d。以流式细胞术检测雏鸡外周血T淋巴细胞亚群变化;用酶联免疫吸附试验(ELISA)检测雏鸡血清IL–2和IFN–γ含量变化。结果显示,与对照组相比,AFB1Ⅱ和AFB1Ⅲ组7、14和21日龄雏鸡外周血CD3+,CD3+CD4+和CD3+CD8+T淋巴细胞百分比下降明显(P0.05或P0.01),血清中IL–2和IFN–γ含量降低(P0.05或P0.01),AFB1Ⅰ组雏鸡14日龄的血清IL–2和7日龄的IFN–γ含量降低(P0.05),表明摄食含黄曲霉毒素B1的日粮可导致雏鸡细胞免疫功能下降。 相似文献
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通过对泰山竹林寺景区引种27年生的日本黑松和赤松精英树半同胞家系生长特性和遗传参数的研究发现:(1)黑松生长量略优于赤松,它们的平均胸径分别为21.83cm和20.84cm,平均材积分别为0.264m^3和0.262m^3。从遗传特性上来看,黑松和赤松的胸径的家系h^2分别为0.7668和0.4404。(2)从家系间比较可知:黑松大岛6^#、黑松柳井3^#、当地黑松、黑松柳井2^#生长指标居于前4位,材积分别为0.4725m^3、0.3526m^3、0.3179m^3和0.3144m^3。赤松都浓3^#、赤松都浓2^#、赤松大岛1^#居于前列,材积分别为0.429m^3、0.343m^3和0.365m^3。 相似文献
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Dasheng?Sun Qingfang?Bi Kejie?Li Peibin?Dai Yan?Yu Weiwei?Zhou Ting?Lv Xipeng?Liu Jun?Zhu Qichun?Zhang Chongwei?Jin Lingli?Lu Xianyong?LinEmail author 《Biology and Fertility of Soils》2018,54(2):229-241
Little is known about the effects of temperature and drying–rewetting on soil phosphorus (P) fractions and microbial community composition in regard to different fertilizer sources. Soil P dynamics and microbial community properties were evaluated in a soil not fertilized or fertilized with KH2PO4 or swine manure at two temperatures (10 and 25 °C) and two soil water regimes (continuously moist and drying–rewetting cycles) in laboratory microcosm assays. The P source was the dominant factor determining the sizes of labile P fractions and microbial community properties. Manure fertilization increased the content of labile P, microbial biomass, alkaline phosphomonoesterase activity, and fatty acid contents, whereas KH2PO4 fertilization increased the content of labile inorganic P and microbial P. Water regimes, second to fertilization in importance, affected more labile P pools, microbial biomass, alkaline phosphomonoesterase activity, and fatty acid contents than temperature. Drying–rewetting cycles increased labile P pools, decreased microbial biomass and alkaline phosphomonoesterase activity, and shaped the composition of microbial communities towards those with greater percentages of unsaturated fatty acids, particularly at 25 °C in manure-fertilized soils. Microbial C and P dynamics responded differentially to drying–rewetting cycles in manure-fertilized soils but not in KH2PO4-fertilized soils, suggesting their decoupling because of P sources and water regimes. Phosphorus sources, temperature, and water regimes interactively affected the labile organic P pool in the middle of incubation. Overall, P sources and water availability had greater effects on P dynamics and microbial community properties than temperature. 相似文献
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1MSF-3型残膜回收机机架的设计与优化 总被引:1,自引:0,他引:1
1MSF-3型残膜回收机的主要承载部件是宽幅可折叠式机架,其强度和刚度直接影响了残膜回收机的正常作业。为此,首先利用Solid Works软件建立宽幅可折叠式机架三维参数化模型,并将模型导入ANSYS Workbench中进行静态特性分析,获得其在作业情况下的等效应力及等效位移云图;其次,基于AWE环境下的Design Explorer模块,采用DOE方法 ,以宽幅可折叠式机架中的各个梁横截面尺寸作为设计变量,以应力和位移为限制条件,质量作为优化指标对机架进行多目标设计优化。结果表明:优化后机架质量减少了10%,满足力学性能要求;机具结构的设计合理,为残膜回收机的设计提供了理论支持。 相似文献
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为了探索国际棉花品级实物标准在恒温恒湿环境下的变化规律,持续多年对恒温恒湿环境下保存的国际棉花品级实物标准的黄色深度和反射率进行检测。将每一实物标准的系列检测数据进行数理分析,拟合得出了每一块实物标准的变化规律及计算公式,可供在棉花品质检测工作中参考。 相似文献