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1.
石灰性土壤交换性盐基组成的测定,通行的方法是采用70%乙醇溶液反复洗盐,再经pH 8.50.1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液进行多次交换处理,测定交换液中的K+、Na+、Ca2+、Mg2+浓度。但此方法常常受操作步骤繁琐,以及土壤中碳酸盐的溶解量因多次浸提而增加的困扰,最终导致测定结果偏高。基于上述原因,选择不同浓度、不同pH的NH4OAc和NH4Cl 10种交换剂,对比分析10种交换剂中的碳酸盐溶解度和土壤交换性钙镁含量。结果表明,pH=8.5 1 mol L-1氯化铵-70%乙醇(CH3CH2OH)溶液较适合石灰性土壤交换性盐基的测定。此新方法是先经70%乙醇(CH3CH2OH)溶液洗盐,再用pH8.5 1 mol L-1氯化铵(NH4Cl)-70%乙醇(CH3CH2OH)溶液进行一次性交换处理,然后测定交换液的K+、Na+、Ca2+、Mg2+浓度,简化了操作程序的同时有效抑制了土壤碳酸盐的溶解,降低了测定结果的偏差。  相似文献   

2.
微池板比色法具有快速批量测定土壤酶活性的潜力,将其应用在农田土壤纤维素和木质素分解有关的β-葡萄糖苷酶(BG)和多酚氧化酶(PPO)活性测定及酶的温度敏感性(EQ10)的研究,尚未见报道。本文应用微池板比色法,在获取缓冲液酸碱度、培养时间和匀浆液水土比优化参数基础上,测定不同种植制度土壤(棉花连作和苜蓿-柳枝稷轮作)的PPO和BG活性及其温度敏感性,评价微池板比色法在土壤酶学研究中的价值。结果表明:pH7的缓冲液、2 h的培养时间和匀浆液水土比(20∶1)为最优的测定参数,其既满足批量分析要求又可提高测定的准确性。棉花连作与苜蓿—柳枝稷轮作土壤的PPO活性没有显著性差异,但BG酶活性轮作土壤显著高于连作土壤,PPO和BG活性均随温度的升高而增加,同时,两种栽培制度土壤并没有引起两种酶的EQ10发生显著性的差异。本研究结果显示,微池板比色法能够比较快速地同时测定多个土壤、多种酶活性,可作为土壤酶学常规分析技术,同时需要根据土壤的特性适度调整主要测定参数。  相似文献   

3.
土壤有效硼测定通常采用甲亚胺-H比色法,该方法前处理(煮沸)过程分析效率低、操作步骤不易掌控,极易给测定结果带来较大误差。为此,以山西省标准土样TCB-2为检测样品,对甲亚胺-H比色法的煮沸提取步骤进行了改进,分别试验了水浴提取、微波提取时间对土壤有效硼测定的影响,确定水浴法最佳提取时间为50 min,微波提取时间为90 s。对国家土壤标准物质GBW07412a检测结果表明,水浴提取和微波提取测定结果与标准参照值符合,相对标准偏差分别为3.43%和8.91%。  相似文献   

4.
土壤脲酶抑制剂正丁基硫代磷酰三胺的作用基团研究   总被引:6,自引:1,他引:5  
孙庆元  张雪崧  王艳红 《土壤》2007,39(3):492-495
土壤脲酶抑制剂正丁基硫代磷酰三胺(nBPT)是抑制土壤中尿素水解的最有效的化合物之一。分析大连工业大学合成的土壤脲酶抑制剂nBPT抑制脲酶活性的影响因素及作用机理,结果表明:在50°C,pH=5.91时,nBPT的抑制活性达到最大值;在nBPT各结构基团中,正丁基(-NH(CH2)3CH3)、硫基(-S)对nBPT与脲酶的结合起辅助作用,胺基(-NH2)是nBPT与脲酶结合的关键基团,与脲酶活性部位巯基(-SH)结合。土壤脲酶抑制剂nBPT与脲酶的具体结合机理还有待继续研究。  相似文献   

5.
以垃圾生物覆盖土、垃圾填埋场覆盖土、菜地土为材料,研究了土壤甲烷单加氧酶(Methane monooxygenase,MMO)活性的测定条件。结果表明:0.04 g kg-1 NaN3含量可抑制土壤生物活性,可作为土壤MMO活性测定时的对照;最适的底物丙烯浓度可为0.5%;培养时间对土壤MMO活性测定影响不大,但从测定的误差和可靠性考虑,可选用5 d作为土壤MMO活性测定的培养时间。统计分析表明:采用该方法测定的土壤MMO活性与其甲烷氧化潜力有很好的线性关系。  相似文献   

6.
常文华  马维伟  李广  徐国荣  宋良翠 《土壤》2022,54(3):524-531
为探讨高寒湿地退化对土壤酶活性的影响,本文以青藏高原东缘尕海湿地未退化、轻度退化、中度退化和重度退化4种不同退化梯度的0~10、10~20和20~40 cm层土壤为研究对象,研究不同退化梯度土壤脲酶与蛋白酶活性时空变化特征。结果表明:随退化梯度加剧,土壤含水量降低,温度升高;土壤脲酶活性在0~40 cm土层中表现为随退化加剧而逐渐降低,而蛋白酶活性趋势恰好相反;除重度退化外,其他退化梯度土壤两种酶活性均随土层加深而降低;0~40 cm土层中脲酶与蛋白酶活性分别在7、8月和6、7月最高;相关性分析表明土壤脲酶活性与蛋白酶活性和温度极显著正相关(P<0.01);土壤蛋白酶活性与微生物生物量氮极显著正相关(P<0.01),与含水量和温度显著正相关(P<0.05),与硝态氮显著负相关(P<0.05)。沼泽化草甸退化显著增加土壤表层脲酶活性而降低蛋白酶活性;温度对土壤脲酶与蛋白酶活性起促进作用,含水量、微生物生物量氮对土壤蛋白酶活性具有促进作用。  相似文献   

7.
为了探明无机肥和有机肥施用对板栗林地土壤 CH4 吸收通量动态的影响,探讨板栗林地土壤 CH4 通量与环境因子之间的关系,在浙江省临安市典型板栗林样地布置施肥试验。于2011年6月~2012年6月期间,采用静态箱-气相色谱法测定了不施肥(CK)、 无机肥(IF)、 有机肥(OF)和有机无机混合肥(OIF)处理下土壤CH4 吸收通量的全年动态变化,并测定了土壤温度、 土壤水分、 水溶性有机碳(WSOC)和微生物量碳(MBC)含量。结果表明,板栗林土壤CH4 吸收通量呈现明显的季节性变化,最大值出现在9月,最小值出现在2~3月;施肥处理均显著抑制了土壤 CH4 的吸收,具体表现为 IF、 OF和OIF处理下土壤CH4年吸收量与CK处理[CH4 3.09 kg/(hm2a)]相比分别减少了7.0%、 1.6% 和 4.4%。此外,施肥显著增加了土壤WSOC和MBC含量(P 0.05),且施肥使土壤碱解氮、 铵态氮、 硝态氮、 全氮和有机质含量均有不同程度的增加。相关性分析表明,土壤CH4 吸收通量与土壤表层5 cm处温度之间呈显著正相关(P 0.05),但与土壤水分、 MBC含量之间没有显著相关性;土壤CH4 吸收与土壤WSOC含量之间(除CK处理外)均具有显著相关性(P 0.05)。因此,施肥引起土壤理化性质[如 NH+4-N、 NO-3-N、 全氮(TN)、 有机碳(SOC)等]和 WSOC 含量的改变可能是施肥显著抑制了板栗林土壤CH4排放的主要原因。  相似文献   

8.
长期施肥对不同有机质水平黑土蛋白酶活性及氮素的影响   总被引:2,自引:0,他引:2  
为了探讨长期施肥对不同有机质含量农田黑土酶活性及养分的影响。本研究以黑土生产力长期定位试验为平台,选取5个不同有机质含量农田黑土为研究对象,对比分析长期施用化肥对农田黑土土壤蛋白酶活性及相关土壤养分的影响。结果表明:5种不同有机质含量农田黑土蛋白酶活性随有机质含量的增加而递增;与长期无肥处理相比,施用化肥显著提高了农田黑土蛋白酶的活性。不同施肥处理间土壤全氮随有机质含量的降低而降低,铵态氮、硝态氮与全氮含量变化一致。相关分析显示,土壤蛋白酶活性与土壤全氮、铵态氮、硝态氮均呈显著的正相关关系(P0.05)。土壤蛋白酶活性可以作为长期施用化肥农田黑土质量评价的灵敏指标。  相似文献   

9.
有机和常规生产模式下菜田土壤酶活性差异研究   总被引:3,自引:0,他引:3  
通过对露地及温室环境下有机和常规蔬菜栽培土壤采样,测定分析了5种参与土壤碳氮循环的酶活性,及其与土壤相关理化性质之间的关系。结果显示:温室及露地土壤EC值在有机生产中相应低于常规生产12%和16%;有机生产土壤微生物碳氮含量显著高于常规生产;不同生产模式下土壤酶活性差异显著,有机生产土壤中的蛋白酶、脲酶、脱氢酶、β-葡糖苷酶活性高于常规生产,而硝酸还原酶活性较常规生产低;有机与常规栽培对蛋白酶活性影响极显著(P=0.006 8),对脲酶活性影响程度达显著水平(P=0.012 4)。除脱氢酶以外,不同栽培模式环境对土壤中另外4种酶活性均有显著影响,温室栽培环境中的蛋白酶、脲酶和硝酸还原酶活性高于露地。除硝酸还原酶外,其他4种酶活性与可溶性全氮、微生物碳、微生物氮相关系数达到显著水平。分析表明,土壤酶活性受到栽培方式以及环境的影响,并且有机生产能够提高参与土壤碳氮循环的酶活性。土壤蛋白酶、脲酶、脱氢酶和β-葡糖苷酶活性能够作为表征土壤碳氮循环以及微生物活性的指标。  相似文献   

10.
不同土壤管理方式下幼龄柑橘根区土壤酶活性动态变化   总被引:3,自引:0,他引:3  
以盆栽2年生纽荷尔脐橙为试材,研究了清耕、自然生草和间种绿肥条件下幼龄柑橘生长期内根区土壤酶活性的动态变化。结果表明,间种绿肥和生草能显著提高柑橘根际土壤脲酶和蛋白酶活性,但2种酶的峰值出现时间不同,脲酶的峰值出现在绿肥成熟期和压青后,而蛋白酶峰值出现在压青前,压青引起蛋白酶活性降低。生草和间种绿肥的柑橘根际土壤过氧化氢酶略高于对照,但3处理间无明显差异;压青会引起过氧化氢酶活性降低,随着绿肥压青后腐解,过氧化氢酶又开始回升。因此,柑橘园内间种绿肥要适时压青。  相似文献   

11.
An optimized method for the determination of protease activity in acid forest soils A method for the determination of protease activity was tested for its applicability to acid forest soils (O-horizon and mineral soil). The influences of the following parameters on the protease activity and its determination were investigated: incubation time, substrate concentration. pH-value of the incubation solution, buffer solution, sample matrix and storage of soil samples. In consequence of the results an optimized method is proposed. The application of this modified method to two forest sites with contrasting N-transformation indicates, that also in acid forest soils the determination of protease activity allows significant differentiations.  相似文献   

12.
测定土壤硝态氮的紫外分光光度法与其他方法的比较   总被引:24,自引:0,他引:24  
宋歌  孙波  教剑英 《土壤学报》2007,44(2):288-293
使用酚二磺酸法、还原蒸馏法、镀铜镉还原.重氮化偶合比色法和改进紫外分光光度法(校正因数法)测定了中国9种不同类型土壤的硝态氮含量,分析了改进紫外分光光度法与其余三种测定方法的差异及其适用性。统计分析表明对于有机质含量低于50g kg^-1的矿质土壤,可以使用2.2作为校正因数,四种分析方法的测定值具有极显著的相关性,尤其是紫外分光光度法与酚二磺酸法的测定结果最为接近,没有极显著差异;对于有机质含量接近和高于50g kg^-1的土壤,校正因数还需要修改。紫外分光光度法具有操作简单、测定速度快等优点,适用于批量快速测定。  相似文献   

13.
通过现场采样及室内分析方法,研究了Cd、Pb严重污染的土壤中蛋白酶、酸性磷酸酶和脱氢酶活性的变化及其与土壤Cd、Cu、Pb、Zn含量和土壤基本性质之间的关系。通径分析表明,影响蛋白酶活性主要直接因素为土壤有效Cd、土壤有效Zn、砂粒和黏粒,其中土壤有效Zn刺激了酶活性而土壤有效Cd抑制了酶活性;影响酸性磷酸酶活性主要直接因素为碱解氮、速效磷、pH值,土壤有效Cu、土壤有效Cd、土壤有效Pb、土壤有效Zn对酸性磷酸酶的直接影响较小;影响脱氢酶活性主要直接因素为土壤有效Cd、土壤有效Zn、土壤速效钾,其中土壤有效Cd抑制了酶活性而土壤有效Zn刺激了酶活性。总体而言,4种重金属有效态对酶活性毒性大小依次为:Cd〉Cu〉Pb〉Zn。综合简单相关分析结果可知,总体上Cu、Cd、Pb、Zn复合污染刺激了蛋白酶活性,抑制了脱氢酶活性,对酸性磷酸酶活性影响不大,脱氢酶可作为上述土壤重金属复合污染的指标。3种土壤酶活性变化是重金属与土壤理化性质综合作用的结果。  相似文献   

14.
Sustainability of agricultural systems has become an important issue all over the world. The activity of enzymes is potentially an important quality bioindicator in soils. The aim of the present study was to develop a simple and convenient assay to determine the activity of arylsulphatase (AS), acid (ACP) and alkaline phosphatase (ALP) in agricultural soil. The activities of these enzymes were detected using a non-electroactive substrate, which produces an electroactive product. To this end, p-aminophenyl phosphate (pAPP) was used as a substrate which is converted to p-aminophenol (pAP) after enzymatic dephosphorylation; and 4-nitrocatechol sulphate (4-NCS) was used as a substrate for AS activity based on its catalytic effect on the hydrolysis of 4-NCS into 4-nitrocatechol (4-NC). The products of both enzymatic reactions were quantified on carbon-based screen-printed electrodes (SPCEs) modified with carbon nanotubes (CNTs), using Osteryoung square-wave voltammetry (OSWV). The determination of the reaction products allowed more sensitive determination of ALP, ACP and AS activities in soil than that obtained with a spectrophotometric method. This assay also diminishes the generation of waste, which is desirable in green analytical chemistry. The optimization of the analytical procedure in terms of the nature of electrode type, applied potential, pH of solution, and precision of measurements is reported.  相似文献   

15.
The origin of soil protease in field soil was estimated using culture-dependent and independent approaches. Overall soil protease activity was much higher in field soils with an annual application of liquid livestock feces (120 t ha−1 year−1 and 600 t ha−1 year−1) compared with the activity recorded in other field soils, and the character of the soil proteases became highly homogeneous (approximately 70% metalloprotease in a 600 t field). Selective incubation studies suggested that bacteria were the most important source of soil protease. There were significantly higher correlations between serratial metalloprotease and the overall soil protease in both feces-applied fields in terms of the effect of inhibitors, and the bacteria, which produced serratial metalloprotease, were suggested to proliferate in both the 120 t and 600 t fields. The gene homologous to serratial metalloprotease gene was amplified in directly extracted DNA from field soils using selective DNA primer and proteolytic Serratia marcescens was certified to be one source of soil protease in these field soils. Proteolytic S. marcescens and its metalloprotease gene have occasionally been isolated and detected in field soils applied with raw feces, and have rarely been isolated or detected from other field soils. Proteolytic S. marcescens is believed to be introduced in the raw feces and subsequently colonizes the field soil and replaces the indigenous bacteria in the soil.  相似文献   

16.
Abstract

A simple procedure is described for the rapid determination of organic carbon content in a large number of soil samples using an automated segmented flow analyser. The method is a modification of the wet oxidation/ digestion methods based on potassium dichromate combined with a colorimetric method for determination of chromic oxide (Stevenson and Clare, 1962). Using a segmented flow analyser for the colorimetry, the procedure is capable of automated routine analyses of large numbers of samples and was shown to give high and repeatable recoveries of organic carbon from a range of compounds. Organic carbon values for a range of soils analysed by the reported method and by the dry combustion technique showed a high correlation.  相似文献   

17.
Abstract: The objective of this study was to determine how the extractant Mehlich 3 (M3) compared with other methods currently used in Ireland for determination of copper (Cu) and zinc (Zn) in soils. Samples from eight different mineral soil types, four of sandstone/shale and four of limestone origin, were analyzed for copper and zinc using M3 and conventional extractants. Herbage samples were taken from the soils and analyzed for Cu and Zn. Mehlich 3 results showed good correlation with ethylenediamine‐tetraacetic acid (EDTA)– and diethylenetriamine‐pentaacetic acid (DTPA)–extractable Cu and Zn. Inclusion of soil properties in multiple regression models improved the coefficients of determination. All extractants were equal in their ability to predict Cu and Zn herbage content. Differences between sandstone/shale and limestone soils in relation to herbage content were also found, with the better relationship found in sandstone/shale soils.  相似文献   

18.
我国主要土壤剖面酶活性状况   总被引:77,自引:1,他引:76  
本世纪五十年代以来,由于科学的发展以及新技术的引入,土壤酶的研究愈来愈为人们所重视。试验研究已证明,土壤酶是土壤的组成分之一。  相似文献   

19.
This study was carried out in order to assess the influence of biochar applications on the estimation of colorimetric‐based enzymatic assays and to verify the effectiveness of the most common methods. Since most methods used to determine enzymatic activities in the soil are based on colorimetry, biochar may absorb substrates and/or coloured products thereby distorting the analytical result. Biochar was added to two soils, with different textures and cation exchangeable capacities, at a rate of 2% (w/w), and seven enzyme activities were determined following standard methods. The biochar amendment lowered the spectrophotometer reading of the activity of FDAase and dehydrogenase in the sandy soil. In the three enzymatic activities based on p‐nitrophenol production (β‐glucosidase, phosphatase and arylsulphatase), the addition of biochar did not change the enzyme assays. The biochar led to an overestimation in terms of the protease and urease activities in the sandy soil. In the clay loamy soil, biochar did not change the response of any of the enzyme activities tested. A biochar dose of up to 2% only guarantees the effectiveness of the most common spectrophotometric methods for not excessively sandy soils.  相似文献   

20.
Fumigation of a field soil with chloropicrin and methyl bromide, either singly or in combination, differentially decreased soil enzyme activities and viable bacterial numbers and increased the amounts of ninhydrin reactive compounds extractable with acidified Tris buffer. Chloropicrin treatment was more effective than methyl bromide.The rates of hydrolysis of both an amide and a peptide derivative were decreased by chloropicrin treatment and remained relatively low despite changes in activities over 325 days. By contrast, caseinase activity initially was decreased by both chloropicrin and methyl bromide fumigation, but activities of the fumigated soils recovered to exceed those of untreated soils. Thereafter, caseinase activities of fumigated and untreated soils exhibited relatively large fluctuations, which were partly associated with seasonal drying of the soils in the field.Chloropicrin but not methyl bromide fumigation markedly depressed the viable bacterial populations, which subsequently increased to be above those of the untreated soils. There was no consistent relationship between the release of ninhydrin reactive compounds following fumigation and changes in bacterial numbers or changes in enzyme activity. Autolytic reactions are probably important in the early stages of amino-nitrogen release in fumigated soils. Net gains in caseinase activity may be partly due to the production de novo of extracellular proteases by microorganisms or to the release of intracellular proteases from killed cells.  相似文献   

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