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作物需水量模拟计算结果有效性检验 总被引：4，自引：2，他引：2
作物需水量是确定节水高效灌溉制度、制定灌溉排水规划和水资源合理配置必不可少的重要参数。当前模拟计算作物需水量的主要方法有FAO-56双作物系数法、双涌源能量守恒模型、根系层水量平衡模型和SWAP模型,而各种方法均有利弊和使用条件。不论采用哪种方法模拟计算作物需水量,其结果必须进行有效性检验,否则不能用于上述工程项目。该文用FAO-56双作物系数法基于灌溉试验数据模拟计算了人工牧草——老芒麦、冰草的需水量,并对模拟计算的需水量采用拟合相关图法、回归分析法和残差估计误差指示法进行了有效性检验。拟合相关图法属定性检验,给出了统计相关趋势;回归分析法和残差估计误差指示法为定量检验,给出了模拟计算值与实测值间的拟合优度和残差估计误差的范围。这种定性定量相结合的方法有效地检验了需水量模拟值与其实测值间的一致性,其结果可用于工程项目中。 相似文献
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基于冠层相对湿度的日光温室黄瓜叶片湿润时间估计模型 总被引：3，自引：3，他引：0
叶片湿润时间是日光温室作物病害预警系统的关键输入,基于相对湿度的叶片湿润时间估计模型（简称RH阈值模型）是最简便的估计模型之一。为了在日光温室实际环境中对模型参数进行校准和检验,以夏末秋初的日光温室盛果期迷你黄瓜为试材,以5 min为间隔自动采集冠层相对湿度数据,采用试错法、平均值法和叶湿频率法3种校准方法对RH阈值进行校准,分别获得相对湿度RH=90%、89%和93% 3个阈值,并采用均方根误差法、回归分析法以及一系列误差分析指标对校准结果进行检验。结果表明：试错法和平均值法的预测效果要显著好于叶湿频率法,误差一般在1～2 h左右;与本试验中普遍超过3 h的叶片湿润时间相比,RH阈值模型监测效果仍然可接受;验证结果中,平均值法的效果反而好于试错法,这说明在实际应用中不能仅局限于一种校准方法。该文总结的模型校准和检验方法,以及构建的基于冠层相对湿度的叶片湿润时间估计模型,可以用于日光温室黄瓜叶片湿润时间监测,符合日光温室黄瓜病害预警系统的要求。 相似文献
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环境水样中高锰酸盐指数的微波消解测定法 总被引：4，自引：0，他引：4
利用微波新技术,对放在密闭容器内的样品进行微波加热处理,能大大加快其反应速度。本实验测定了不同水样中的高锰酸盐指数,讨论了微波功率、微波时间、酸度等因素对分析结果的影响,并与标准方法相对照,用F-检验法及t-检验法检验,没有明显差异,多次加标回收率在98.0%—103%之间,RSD≤1.2%,结果令人满意。该法具有省时、省力、经济、不污染环境、便于普及推广、宜于批量分析等优点。 相似文献
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采用反距离加权法(IDW),克里格法(Kriging),径向基函数法(Spline)对河南省安阳县385个土壤样点的全氮进行空间插值,通过交叉验证和样点检验对不同空间插值方法进行分析,结果表明,Spline优于IDW和Kriging,并且不同插值方法有不同的最优插值点数;基于不同样条函数的径向基函数法插值结果的平均相对误差MRE不同,其中平面样条函数表现最差,高次曲面函数,张力样条函数、规则样条函数和反高次曲面函数之间差异不显著。检验分析结果也显示,Spline优于IDW和Kriging,因此,相对于IDW和Kriging,Spline更适合用于全氮的空间插值。 相似文献
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为研究贵州地区降水的时空演变规律,根据贵州省84个气象站1961-2017年的降水量资料,利用EOF和REOF方法、Mann-Kendall检验、Cramer法、YAMAMOTO法和滑动t检验及Morlet小波分析法,对贵州地区57年来降水的空间分布、时间系数变化特征和时间序列的趋势性、突变性及周期性进行了分析。结果表明:EOF方法可以很好地解释降水场的时空分布特征,前2个特征向量累计贡献率达50.08%,揭示了两种典型的分布场,即全局型和东西反向型。分析特征向量所对应的时间系数,贵州省的降水场主要表现为全省多雨、全省少雨、东多西少、东少西多4种类型,REOF可将贵州降水场分为东西部两个区域,通过Mann-Kendall检验发现均存在降水减少的突变,并通过Cramer法、YAMAMOTO法和滑动t检验对结果进行验证,发现Ⅱ区比Ⅰ区降水突变明显。Morlet小波分析表明,贵州地区降水存在着显著的28 a周期变化。 相似文献
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付梁 《山西水土保持科技》2012,(3):18-20
土挤密桩法由原苏联阿别列夫教授于1934年首创,并在工程中得到广泛应用。我国自20世纪50年代中期开始在西北黄土地区进行土挤密桩法的研究和应用。在万家寨引黄入晋北干线金沙滩水库工程的大坝基础处理中,采用了素土挤密桩法,取得了较好的加固效果。介绍了素土挤密桩法的技术参数、施工方法及检验结果。 相似文献
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气候变化情景下新疆棉花和甜菜需水量的变化趋势 总被引：3，自引：0，他引：3
利用改进的非参数统计检验Mann-Kendall(MK)方法进行序列趋势检验时,因考虑了时间序列自相关性的影响而使检验结果更趋严格。本文采用MK法及改进的MK法对新疆地区41站1961-2010及2015-2099年主要经济作物棉花和甜菜需水量ETc和相关气候要素的变化趋势进行了检验,探讨了序列自相关性对ETc趋势检验结果的影响,并给出了各站及全疆ETc的变化趋势。结果表明:1)当自相关阶数大于0时,应采用改进MK法判断ETc的变化趋势;2)1961-2010棉花和甜菜的ETc具有一定的相依结构,2015-2099年棉花的ETc具有非常明显的长程相关性,但2015-2099年甜菜的ETc均具有时间独立性;3)无论对于棉花还是甜菜ETc,各站点Sen斜率和线性斜率值很接近,满足极好的线性关系,表明两者在反映趋势幅度时具有高度一致性;4)ETc序列是否存在相依性对于趋势显著性有重要影响,最终的趋势检验需用MK法和改进的MK法综合判断。1961-2010和2015-2099年棉花和甜菜的ETc在多数站点呈下降趋势,但其显著性各异。ETc序列的下降说明未来新疆棉花和甜菜用水需求降低,遭受干旱的风险降低。棉花及甜菜ETc的趋势特征对于气候变化背景下干旱-半干旱区作物灌溉制度的制定和防灾抗旱有重要参考价值。 相似文献
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利用复州河流域1956～2008年径流量和降水量资料,通过一元线性回归、Speaman秩次相关检验法、Man-Kendall秩次相关检验法,进行流域径流与降水比对分析,检验径流变化的趋势性。根据径流总体下降速率大于降水的检验结果,利用径流与降水Man-Kendall趋势线对比结果,采取分时段径流系数与降水变化比对分析,探讨径流趋势的演变过程,揭示了流域产汇流形成机制的改变和水资源蜕化这一深层次问题。 相似文献
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土壤有效硫测定方法的探讨 总被引：2，自引：1，他引：1
在测土配方施肥土壤有效硫分析测定工作中,对土壤有效硫的测定方法(常规法)进行了改进。1.常规法中加入1.0 g氯化钡晶粒改为加入10%浓度氯化钡液体1 mL;2.常规法中过氧化氢加热脱有机质改为加入0.04～0.05 g活性炭脱有机质。改进法比常规法操作简单、省时、省力;在标准曲线绘制中,获得的标准曲线相关性都达到0.995以上;对山西省标准土样TCB-2进行了平行测试,测试值全部在标准值(62.7±20.4)mg/kg范围之内,且平行相对相差≤10%。 相似文献
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Simple, rapid cleanup method for analysis of aflatoxins and comparison with various methods 总被引：1，自引：0，他引：1
H Kamimura M Nishijima K Yasuda H Ushiyama S Tabata S Matsumoto T Nishima 《Journal of the Association of Official Analytical Chemists》1985,68(3):458-461
A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ether-methanol-water (94 + 4.5 + 1.5) or chloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (micrograms/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1, M1. Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 micrograms/kg were greater than 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method. 相似文献
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Li X Luo P Tang S Beier RC Wu X Yang L Li Y Xiao X 《Journal of agricultural and food chemistry》2011,59(11):6064-6070
A simple, rapid and sensitive immunogold chromatographic strip test based on a monoclonal antibody was developed for the detection of melamine (MEL) residues in raw milk, milk products and animal feed. The limit of detection was estimated to be 0.05 μg/mL in raw milk, since the detection test line on the strip test completely disappeared at this concentration. The limit of detection was 2 μg/mL (or 2 μg/g) for milk drinks, yogurt, condensed milk, cheese, and animal feed and 1 μg/g for milk powder. Sample pretreatment was simple and rapid, and the results can be obtained within 3-10 min. A parallel analysis of MEL in 52 blind raw milk samples conducted by gas chromatography-mass spectrometry showed comparable results to those obtained from the strip test. The results demonstrate that the developed method is suitable for the onsite determination of MEL residues in a large number of samples. 相似文献
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C.M. Changa P. Wang M.E. Watson H.A.J. Hoitink F.C. Michel Jr. 《Compost science & utilization》2013,21(2):125-143
Stability significantly affects the potential for beneficial utilization of composts but is difficult to measure by farmers and compost producers. A simple four hour test (the Solvita® maturity test) that measures CO2 evolution and ammonia emission from compost samples was compared to a traditional three-day, 25°C, CO2 evolution rate procedure and to measurements of ammoniacal nitrogen concentrations in manure composts to assess the reliability of this test. Three composts — 1) Dairy manure amended with wheat straw, 2) The same dairy manure but amended with sawdust and 3) Swine manure amended with sawdust and ground wood pallets — were composted in windrows for 120 days. Samples were removed weekly to biweekly. CO2 evolution rates of the three composts decreased from initial means (n=6) of 3.41, 3.42 and 9.35 to 0.63, 0.76 and 0.31 mg CO2-C g?1 VS day?1, for the dairy manure-straw, dairy manure-sawdust, hog manure composts, respectively. The corresponding mean Solvita CO2 test values for these composts increased from 3.4, 3.0 and 3.2 to 6.8, 6.5 and 7.0, respectively. Correlation analysis between CO2 evolution rates and Solvita CO2 test values gave linear correlation coefficients (r) of ?0.82, ?0.78, and ?0.87 for the straw-amended dairy manure, the sawdust-amended dairy and the hog manure composts, respectively. The Solvita NH3 test gave highly significant correlations (p<0.0001) with ammoniacal-N concentrations (correlation coefficients (r) = ?0.43, ?0.64 and ?0.65, respectively). The Solvita® maturity index, a combination of Solvita CO2 and NH3 values, correlated significantly with both CO2 evolution rate and ammoniacal-N concentrations. However, the Solvita CO2 index alone was the best predictor of compost CO2 evolution rate or stability. The Solvita Maturity test, which combines the Solvita CO2 and NH3 tests, provided useful information about the potential for the development of a toxic response in plants due to excessive concentrations of ammoniacal-N present in some stable compost samples that would not have been detected if the CO2 stability test were used by itself. We conclude that the Solvita maturity test provided a simple, inexpensive relative test of compost stability and NH3 emission for diverse samples of composted manures. Even so, it did not accurately predict their CO2 evolution rates measured by respirometry nor their ammoniacal-N concentrations. The test would be most useful for on-farm applications. 相似文献
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Masahide Aikawa Yoshinori Nishikawa Makiko Yamagami Takatoshi Hiraki Kentaro Murano Hitoshi Mukai 《Water, air, and soil pollution》2010,208(1-4):183-191
We evaluated the applicability of a simple passive sampling method to quantify HNO3(g) in ambient air. The method has the advantages of not only ease of operation but also low cost. A sampling velocity of 214 m day?1 was determined based on the concentration of HNO3(g) measured by the four-stage filter-pack method at nine sites located within a 250?×?250-km area in Japan. This sampling velocity was applied at sites located outside of area to verify the applicability and accuracy of the simple passive sampling method. The variation in the results for the application of the sampling velocity ranged from 0.39 to 0.95. The simple passive sampling method should be applied to sites with different meteorological conditions, and the obtained data should be used to obtain more significant information and/or to indicate the need for further developments in the methodology. 相似文献
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C S Shen I S Chen A J Sheppard 《Journal of the Association of Official Analytical Chemists》1982,65(5):1222-1224
The quantitative determination of cholesterol in egg yolk by using an enzymatic test kit is described. Cholesterol in the egg yolk is extracted with other lipid components by methylene chloride-methanol (2 + 1) and is enzymatically determined after saponification of the lipid extract. The method is relatively rapid, simple, and accurate and gives results which agree with those obtained by using a gas-liquid chromatographic (GLC) method. The mean cholesterol content of egg yolk determined by the enzymatic and GLC methods was 1237 and 1240 mg/100 g, respectively. 相似文献
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提出一个测定Cl- —交换性碱的方法。用自动控制pH的滴定装置定量地研究了一个砖红壤胶体和一个红壤胶体在NaCl和Ba(NO3) 2 溶液中的交换性酸的变化。结果发现 ,砖红壤和红壤胶体在两种盐溶液中 ,在测定pH范围内只出现交换性酸 ,红壤胶体的交换性酸量比砖红壤胶体的大。随着盐浓度的增高 ,交换性酸量的增幅由大变小 ,明确地出现一折点 ,NaCl在 30 0mmolkg- 1左右 ,Ba(NO3) 2 在 1 2 0mmolkg- 1左右。pH对交换性酸有显著影响 ,在Ba(NO3) 2 溶液中随pH升高而增大 ,在NaCl溶液中则出现一峰值。 相似文献
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Thirumalaiandi Ramasubramanian Mariappan Paramasivam Ramabhadran Jayanthi 《Water, air, and soil pollution》2012,223(9):6045-6050
A rapid, simple, sensitive and cost-effective analytical method has been standardised to determine the residues of imidacloprid and thiamethoxam in soil. This method does not require any cleanup with costly sorbents. The recoveries of imidacloprid and thiamethoxam obtained in this no-cleanup method were on par with the protocol involving primary?Csecondary amine-based cleanup. This method requires less volume of solvent (20?mL of acetonitrile/sample) and is suitable for high throughput analyses involving large number of samples. The limit of quantification of the method was 0.01???g/g. Dissipation kinetics of imidacloprid and thiamethoxam in the soils of sugarcane ecosystem was studied by adopting this rapid method. The half-life of imidacloprid and thiamethoxam was 9.07 and 6.22?days when applied at 70 and 100?g a.i./ha, respectively. The dissipation of both the neonicotinoids followed first-order kinetics with good fit. 相似文献
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为了预测鲜枣常温贮藏的保鲜期,确保鲜枣的品质要求及食用安全,应用近红外光谱建立了室温贮藏下鲜枣内部霉菌菌落总数变化的动力学模型。通过对几种数据预处理方法的比较及特征波数的选择,实现了鲜枣霉菌菌落总数变化的近红外模型的优选。结果表明:经过多元散射校正处理的鲜枣近红外光谱,应用多元线性回归方法建立的霉菌菌落总数模型预测能力较好,校正集相关系数为0.920,均方根误差为1.503,预测集相关系数为0.889,均方根误差为1.514。同时,将近红外光谱模型应用于霉菌菌落总数随贮藏时间变化的零级反应动力学模型中,得到模型的相关系数为0.981。根据近红外光谱吸光度值与贮藏时间的线性关系,当霉菌菌落总数初始值小于等于10cfu/g时,预测出鲜枣在室温下的保鲜期一般为8d。研究表明,结合动力学模型的近红外光谱技术可以作为一种无损、快速检测方法来检测鲜枣霉菌菌落总数变化。 相似文献