圆叶决明添加量对红壤可溶性氮及酶活性的影响     

钟珍梅  杨庆  游小凤  邢世和 《草地学报》2022,30(3):622-630

为了探明圆叶决明(Chamaecrista rotundifolia)降解后红壤可溶性氮及氮水解酶活性的变化规律,本研究采用室内好气恒湿培养法,研究占红壤质量0.5%(T1),1%(T2)和2%(T3)的圆叶决明添加至红壤中,培养7~88d内红壤硝态氮(NO^-₃-N)、铵态氮(NH⁺₄-N)和可溶性有机氮(Soluble organic nitrogen,SON)及脲酶、蛋白酶和天冬酰胺酶的变化。结果表明：添加圆叶决明后,红壤NO^-₃-N和NH⁺₄-N含量在培养前期降低,培养中期增加;而整个培养期SON含量及脲酶、蛋白酶和天冬酰胺酶活性均增加,且圆叶决明添加量越大,效果越显著。NO^-₃-N和SON含量及脲酶、蛋白酶和天冬酰胺酶活性可用2次或3次函数方程拟合;而NH⁺₄-N含量可用线性函数拟合。氮水解酶与NO^-₃-N负相关,与NH⁺₄-N和SON正相关,且相关性从大到小的顺序为蛋白酶>天冬酰胺酶>脲酶。综上,添加圆叶决明提高了红壤供氮水平和红壤氮转化能力。  相似文献   

季铵盐类化合物(QAC)在木材防腐中的应用     

姜卸宏  曹金珍 《林产工业》2007,34(2):3-8

主要综述了季铵盐类化合物(QAC)在用作木材防腐剂时的耐腐性、抗流失性及其与木材的结合机理等方面的研究概况,分析了实验室耐腐性和野外实验耐腐性结果不一致的原因。此外也介绍了对季铵盐进行改性处理方面的一些研究进展。  相似文献   

DETERMINATION OF STATIC AND DYNAMIC DIFFUSION COEFFICIENTS OF MOISTURE IN PARTICLEBOARDS     

Dai Fangtian Cai LipinNortheast Forestry UniversityZhang ShufenWeihe Forestry Bureau  Heilongjiang Province 《林业研究》1993,4(2):87-92

The static and dynamic diffusion coefficients are important coefficients todescribe the moisture transfer processes in particleboard.In this paper,the formula ofculculating the static and dynamic diffusion coefficients were deduced.At first,the staticdiffusion coefficients of four kinds of particleboards were determined by using diffusion cupmethod.The results demonstrated that the static diffusion coefficients parallel to panelsurface were 10-20 times as large as that of perpendicular to panel surface for test boards.To determine both dynamic diffusion coefficients and surface emission coefficients ofmoisture in particleboards in one experimental period,specimens in four different thickness-es of each kind of particleboard were used in the experiment.Then the method ofregression was used and the dynamic diffusion coefficients and surface emission coefficien-ts were determined based on the slope and intercept of the regressive line.  相似文献   

竹材热压干燥过程中的水分扩散研究     

孙照斌 《木材工业》2006,20(5):27-29

采用非稳态法测定龙竹竹材热压干燥过程中的水分扩散系数,并探讨了温度对水分扩散系数的影响.结果表明:干燥温度越高,干燥各阶段水分扩散系数及平均水分扩散系数也越大;初始高含水率阶段,随含水率逐渐降低,水分扩散系数呈逐步增加趋势,在纤维饱和点附近时达最大值;随后,随含水率逐渐降低呈逐步减少趋势.  相似文献   

Thermal diffusion in Masson pine wood     

Li Xian-jun Zhang Bi-guang Li Wen-jun 《中国林学(英文版)》2005,7(2):47-51

In order to analyze the effects of the temperature gradient on moisture movement during the highly intensive microwave-vacuum drying, thermal diffusion of Masson pine wood was studied. Internal distribution of temperature and moisture in Masson pine samples sealed by epoxy resin and aluminum foil was measured, the magnitude of thermal diffusion was calculated and the influencing factors of thermal diffusion were discussed. Results showed that with the transfer of moisture toward the low temperature in wood, opposite temperature and moisture gradient occurred. The initial moisture content （MC）, temperature and time are important factors affecting this process; the thermal diffusion is in proportion to wood temperature, its initial moisture and time. The temperature and distance from hot surface is strongly linearly correlated, and the relationship between MCs at different locations and distance from the hot end surface changes from logarithmically form to exponentially form with the increase in experimental time.  相似文献   

In vivo diffusion characteristics following perineural injection of the deep branch of the lateral plantar nerve with mepivacaine or iohexol in horses          下载免费PDF全文

E. K. Contino  M. R. King  A. Valdés‐Martínez  C. W. McIlwraith 《Equine veterinary journal》2015,47(2):230-234

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不同铵硝配比对辣椒产量、养分积累和氮肥利用率的影响     

袁嫚嫚  邬刚  王家宝  井玉丹  张祥明  王文军  陈俊阳  孙义祥 《中国瓜菜》2022,(2):43-48

通过设施大棚辣椒盆栽试验,设置不施氮肥(CK)、铵态氮与硝态氮的氮质量比分别为0:100(A0N100)、25:75(A25N75)、50:50(A50N50)、100:0(A100N0)5个处理,研究不同铵硝态氮配比对辣椒产量、养分积累和氮肥利用率的影响.结果表明,与CK相比,不同铵硝配比处理增加了辣椒的果实数、鲜果...  相似文献   

扰动扩散流动分析法测定土壤氮、磷技术研究     

李灿  李振峰  马刘正  张伟  李晓冬  VIJAYA Raghavan  胡建东 《农业环境科学学报》2022,41(8):1846-1854

随着国家对农业面源氮、磷污染防治力度的加大,土壤氮、磷测定技术迫切需要改善。本研究在对常规的扩散对流（Dispersion convection）和强迫对流（Forced convection）流动分析方法基础上,提出了扰动扩散（Perturbation diffusion）流动分析方法,以实现土壤氮、磷全自动化快速测定与分析。扰动扩散流动分析方法是将样品和试剂定量化后集中在化学反应腔中进行反应,然后程序控制蠕动泵对化学反应腔中反应物进行反复扰动,待化学反应完全稳定后流入光电探测单元完成土壤氮、磷含量测定。采用取自湖北潜江的土壤样品对扰动扩散流动分析方法进行了系统验证,实验结果表明,本研究提出的方法与常规紫外可见分光光度法对氮、磷测定相比,基于硫酸钠和碳酸氢钠联合浸提的土壤铵态氮测量值相关系数为0.915 5,基于氯化钙浸提的土壤铵态氮、硝态氮和水溶性磷测量值相关系数分别为0.998 5、0.990 1和0.991 1。铵态氮、硝态氮和水溶性磷的检出限分别为0.055 4、0.020 3 mg·L^-1和0.008 4 mg·L^-1,相对标准偏差（RSD,n=7）分别为1.8%、4.8%和1.0%。  相似文献   

西庄斜发沸石对NH^＋4的吸附性能研究   总被引：3，自引：0，他引：3  

李健  袁有宪 《海洋水产研究》1993,(14):79-88

对潍坊西庄斜发沸石对NH_4~+的吸附性能,改型和再生方法进行了研究。并与浙江斜发沸石进行了比较。随海水盐度的增高,NH_4~+的去除率降低。不经改型的沸石,对盐度为28.2的海水中5mg/L NH_4~+,5h后的去除率为30％;对淡水,去除率为100％。在室内水泥池和室外大规模生产应用试验表明,在静止的水体中采用自然沉降法去除NH_4~+,去除率可达24.4％～70.0％,从而,提高了对虾的成活率和生长速度。  相似文献   

Comparison of Antioxidant Activity and Antioxidant Components in Lettuce,Onion and Tomato Obtained with Different Levels and Forms of Nitrogen Fertilization     

Ragab Abdelmohsen E-Mergawi  ;Khalid Naser Al-Redhaiman  ;Hussein F. Abouziena 《农业科学与技术》2014,(7):597-604

The effect of N levels and sources on the antioxidant components in vegetable is not completely understood. Therefore, greenhouse experiments were conducted to determine the changes in antioxidant capacity diphenyl-2-picrylhydrazyl （DPPH） and ferric reducing antioxidant power （FRAP）, total phenolics, ascorbic acid, total carotene and lycopene contents in edible portions of lettuce, onion and tomato due to different nitrogen levels and sources. The experiment included three N levels （20, 40 and 60 kg/ha for lettuce trial and 60, 120 and 180 kg/ha for either onion or tomato） and four nitrogen sources （calcium nitrate, ammonium sulphate, ammonium nitrate and urea）. The antioxidant capacity and phenolic contents in lettuce was enhanced under low nitrogen level, while the antioxidant capacities, phenolics, carotenoids and lycopene in tomato fruits were not significantly affected by the nitrogen dose applied. Application of calcium nitrate caused 50% increase in DPPH and 20% in FRAP of lettuce compared to other nitrogen forms. Tomato treated with calcium nitrate or ammonium sulphate had higher phenolic and ascorbic acid contents than treated plants with ammonium nitrate or urea. Antioxidant tested parameters of onion were not significantly affected by the nitrogen treatments. Nitrogen concentration in tomato fruits significantly correlated with FRAP antioxidant capacity, phenolics, ascorbic acid, carotene and lycopene contents.  相似文献