无土栽培基质速效磷测定方法的研究

将4种土壤速效磷测定方法 [Olsen法(常规方法)、Bary1法、ASI法、Mehlich3法]用于无土栽培基质速效磷的测定,结果表明:在显著水平α=0.05,ASI法与Olsen法测定的速效磷没有显著性差异,而Bary1法和Meh-lich3法与Olsen法测定的速效磷存在极显著性差异,故ASI法可用于无土栽培基质速效磷的测定。     

常规浸提剂与联合浸提剂测定我国北方石灰性土壤有效磷钾的比较

使用常规浸提剂与两种联合浸提剂Mehlich 3(M3)、ASI分别测定了中国8个地区10种土壤样品的有效磷、速效钾含量,分析比较了常规浸提剂与两种联合浸提剂测定土壤有效磷速效钾的差异性及相关性。统计分析表明,对于有效磷,M3、ASI两种联合浸提剂的浸提结果均大于常规浸提剂的浸提结果,且M3浸提剂浸提结果的变幅较常规浸提剂浸提结果相对较小,而精确度较高。相关分析表明,常规浸提结果与M3浸提结果呈极显著正相关(P0.01),相关系数为0.680。对于速效钾,M3浸提剂的浸提量较常规浸提剂相近,常规浸提量与M3浸提量呈极显著正相关(P0.01),相关系数为0.996。综合而言,M3这种联合浸提剂是测定土壤有效磷、速效钾的理想浸提方法。     

不同土壤类型Mehlich3方法与常规方法测定土壤养分相关性研究

采取Mehlich3(以下简称M3)方法和常规标准方法测定了土壤有机质、有效磷和速效钾,分析了两种测定结果的相关性,得出水稻土有效磷相关系数为0.8529,速效钾相关系数为0.8655。草甸土土壤有机质Mehlich3方法与常规方法相关系数达到为0.9659,有效钾Mehlich3方法与常规方法相关系数达到0.9606。M3方法与常规方法测定土壤养分有一定的相关性,其数值可以相互转换利用。     

菜园土壤有效钾提取方法比较研究——以重庆地区为例

研究菜园土壤有效钾的测定方法,为蔬菜合理施用钾肥提供理论依据。以36个莴笋钾肥田间试验的产量及吸钾量为参比标准,采用7种方法 (醋酸铵法、ASI法、Mehlich3法、冷硝酸法、四苯硼钠法1、四苯硼钠法2和沸硝酸法)测定土壤有效钾含量。结果表明,土壤有效钾含量以沸硝酸法四苯硼钠法2四苯硼钠法1冷硝酸法Mehlich3法醋酸铵法ASI法。7种测定方法测得的土壤有效钾含量间呈不同程度正相关,均具有评价土壤钾素有效性的潜力。四苯硼钠法1和四苯硼钠法2测得的土壤有效钾含量与无肥区占施钾区莴笋相对产量(RY_(CK))、缺钾区占施钾区莴笋相对产量(RY_(NP))、无肥区占施钾区莴笋相对吸钾量(RUK_(CK))的相关性均达显著水平,即其测得的土壤钾素的生物有效性均较好。综合而言,在所试验土壤地区,四苯硼钠法1和四苯硼钠法2均是评价菜园土壤当季钾素有效性的较好方法,其中以四苯硼钠法1更好。     

常规方法准确测定土壤有效钾素变化可能性的探讨

土壤中的有效钾状况通常用1 mol L-1中性醋酸铵提取的速效钾或1 mol L-1硝酸煮沸法提取的缓效钾量来表征。我国农田土壤中近些年来1 mol L-1中性醋酸铵提取的速效钾量呈普遍下降趋势。但土壤中的有效钾素的实际下降值,到目前为止还没有办法通过测土的方法进行准确评估。本文通过室内培养实验,人为改变土壤有效钾量,对常规土壤有效钾测定方法反应土壤有效钾素变化的效果进行了比较和评价。并对硝酸连续提取法准确测定土壤钾素变化的可能性进行了探讨。结果表明,几种提取方式中,以2 mol L-1冷硝酸超声波连续提取10次获得的外源钾变化的回收率最高,达75%~80%。其次是1 mol L-1硝酸100℃水浴法连续提取6次,测钾变化的累计回收率可达75%。如进一步增加提取次数,可能会有限地提高测钾变化的回收率,但随提取次数的增加,提取过程的可操作性和结果的稳定性将显著下降。因而用硝酸作为提取剂,即使是在高温、超声波等方式下,也很难准确测定强固钾能力土壤中有效钾的变化。能够准确测定土壤有效钾素变化的方法必须能将土壤中易发生变化的有效态钾全部提出,并尽量不提取土壤的原生矿物态钾,寻找这一方法将是未来土壤钾素测定工作中值得关注的问题。     

Mehlich 3法与常规分析方法在测定土壤有效P、K的比较研究

采用Mehlich 3法和常规分析方法测定赤红土和红土的有效磷、有效钾,结果表明,Mehlich 3法测得的有效磷、有效钾与常规方法测定的呈显著的相关。赤红土上的玉米生物试验结果表明:Mehilch 3法测定的土壤有效磷、有效钾含量与玉米吸收的磷、钾量以及玉米的株高、干重呈显著相关。     

Mehlich3方法与常规方法测定土壤养分相关性初步研究

采取Mehlich3(以下简称M3法)方法和常规标准方法测定了41个土壤样品的有效磷、速效钾、交换性钙、交换性镁、有效铁、有效锰、有效铜、有效锌和有效硼。通过对两种方法测定结果的分析,探讨二者的相关性。土壤有效磷M3方法与常规方法相关系数达到0.9085,为最高,有效铜M3方法与常规方法相关系数为0.1556,为最低。有效铜、有效硼测定结果的相关性很差。M3方法与常规方法测定土壤养分在有效磷、速效钾、交换性钙、交换性镁、有效铁、有效锰、有效锌上达到极显著水平,其数值可以通过回归方程相互转换利用。     

应用离子交换树脂膜测定土壤钾素有效性的研究

用国产离子交换树脂膜室内埋置法提取测定了我国北方24种土壤的速效钾含量.结果表明,用阳离子交换树脂膜提取的土壤钾与用1mol/L中性NH4OAc及土壤养分综合系统评价方法提取的钾(ASI-K)分别呈显著和极显著的正相关;与盆栽试验不施钾处理玉米幼苗吸钾量呈极显著的正相关,明显高于常用的1mol/L中性NH4OAc提取钾与盆栽试验玉米幼苗吸钾量之间的相关性.说明可以用国产离子交换树脂膜较好地评价北方土壤的供钾能力.     

不同浸提剂提取的土壤磷铝与油茶各器官磷铝含量的相关分析

采用Mehlich3、ASI、Bray、DTPA、HCl等5种浸提方法测定油茶林地土壤磷、铝含量,并分析其与叶片等器官磷、铝含量的关系。结果表明:ASI法提取的磷含量最高,平均值达4.12 mg/kg,Bray法提取的磷含量最低;铝提取量依次为HCl-AlBray-AlM3-AlASI-AlDTPA-Al。5种方法提取的磷、铝含量分别存在较好的正相关关系。油茶叶片的磷含量和铝含量最高,其中铝含量达14.22 g/kg,是其他器官铝含量的11.5~28.1倍。叶片磷含量与HCl-P、叶片铝含量与HCl-Al分别呈显著正相关。该研究表明0.01 mol/L HCl提取法具有应用于同时测定土壤磷、铝含量和评价其对油茶生物有效性的可行性。     

稀盐溶性磷表征石灰性土壤供磷能力的研究

稀盐 ( 0 .0 1mol/LCaCl2 )提取的磷与冬小麦相对吸磷量的线性相关系数r为 0 734 ,达 0 0 1 %显著水平 .与其他化学方法 (如Olsen、Machigin、Al-Abbas、MehlichⅢ、Mesheryakov)和电超滤法 (EUF)的相关性也达 0 1 %显著水平 .该法操作简便、快速、经济 ,还可以在同一提取液中同时测定氮、磷、钾及其它营养元素 ,是测定石灰性土壤有效磷的可靠方法     

Evaluation of Agro Services International Soil Test Method for Phosphorus and Potassium

Soil testing is widely adopted as an essential diagnostic tool for identifying soil nutrient factors that limit sustained crop production. A systematic approach for rapid soil testing and fertilizer recommendation has been introduced and widely used in China by Agro Services International (ASI), USA. To verify the usefulness and reliability of the ASI method in soil testing and fertilizer recommendation in comparison with other commonly used traditional soil testing methods, 294 soil samples from major agricultural regions and soil types in China with a wide range of soil pH, from 5.1 to 8.9, were taken and analyzed for available phosphorus (P) and potassium (K) by the ASI multielement extraction solution and selected traditional methods, Olsen extractant for P, ammonium acetate (NH₄OAc) extractant for K, and multielement extractant Mehlich 3 for P and K. Also, 46 soils were selected from northern China regions for a greenhouse trial with sorghum seedlings to determine if the soil testing values correlate well with plant response. Results indicated that the amount of soil P extracted by the ASI method (ASI P) was correlated to both soil extractable P tested by the Olsen extractant (Olsen P) and Mehlich 3 extractant (Mehlich 3 P). The correlation coefficient of ASI P with Mehlich 3 P (R² = 0.86) was greater than that of ASI P with Olsen P (R² = 0.74) across all selected soils. A good correlation was also found between the exchangeable K from the ASI method with the traditional ammonium acetate method (R² = 0.81) and the Mehlich 3 method (R² = 0.85). The results from the greenhouse trial showed that the extractable P and exchangeable K by the ASI multielement extraction solution could be used to represent the fertility status of soil P and K for the selected soils. Regression analysis indicated that the relative dry-matter yield of the sorghum plants can be predicted with either ASI P and ASI K values with the correlation coefficients (R²) values of 0.78 and 0.72 respectively and could be a good measure for soil testing and fertilizer recommendation in the selected soils and regions in China.     

酸性土壤有效汞提取方法研究

为了更好地评价酸性土壤中汞的生物有效性和生态风险,以酸性土壤为供试土壤,通过比较国内外几种常用的土壤有效汞的浸提剂的提取效果,筛选适合于酸性土壤的有效汞浸提剂并优化相应的提取条件,从而建立酸性土壤有效汞的提取方法。结果表明,在0.1 mol·L-1HCl、1 mol·L-1NH4OAc、0.005 mol·L-1DTPA、0.03%TGA-1/15 mol·L-1Na2HPO4这4种常用浸提剂中,0.03%TGA-1/15 mol·L-1Na2HPO4是最佳的浸提剂,因为它具有最高的提取率,且其所提取的有效汞与相应稻米中Hg含量的相关性最好。0.03%TGA-1/15 mol·L-1Na2HPO4的最佳浸提条件为土液比1∶10、振荡时间120 min、振荡速度250 r.min-1,浸提出的有效汞量与油菜的相关性达到极显著相关,能较好地指示田间条件下土壤汞对作物的可给性。     

Comparison of extractants for the determination of available phosphorus,potassium, calcium,magnesium and sodium in some Ethiopian and German soils

Abstract

A study was conducted with the purpose of comparing the efficiency of Mehlich 1, Mehlich 3, and calcium acetate lactate (CAL) extractants for the deter‐ mination of available phosphorus (P) and exchangeable cations [potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na)] on 22 Ethiopian and 10 German agricultural soils. The Olsen and NH₄OAc extractants were used as standards against which P and exchangeable cations values were compared. Results showed that, in general, highly significant correlations were found between all of the methods for available P and exchangeable cations determination on the Ethiopian soils. The highest correlation was, however, found with the Mehlich 3 extractant. On the ten soils from Germany, the Olsen method did not give significant cor‐ relation with the CAL method for P determination. The CAL and Mehlich 3 extrac‐ tants were also not good indicators of Na availability when compared with the NH₄OAc method. It can be generalized that the Mehlich 3 is a suitable extractant for P, K, Ca, Mg, and Na in Ethiopian soils, but further study is recommended to confirm these findings under field conditions.     

土壤养分状况系统研究法在土壤肥力研究及测土施肥中的应用

土壤养分状况系统研究法应用美国国际农化中心的ASI联合浸提液(0.25mol/L NaHCO3-0.01mol/L EDTA-0.01mol/L NH4F)测定土壤中11种大、中、微量元素含量,结合土壤对营养元素的吸附研究和盆栽试验,判断土壤中存在的和潜在的养分限制因子,用以指导田间试验和施肥推荐。在全围17个省(市、自治区)范围内选取了140个土壤样品,应用该方法对土壤养分状况进行了研究。盆栽试验结果表明,土壤中氮、磷、钾、锌、硫、铜、硼、锰、钼、镁、钙和铁成为限制因子的土壤分别为137、126、84、68、45、37、36、34、28、25、20和17个。应用Cate和Nelson的方法估计出11种元素(钼除外)测定值在盆栽条件下的临界值。 应用在原取土地块安排的田间试验的资料估计出大田条件下应用ASI联合浸提液测定的土壤磷、钾含量的临界值分别为15mg/L和90mg/L。应用河北省玉田县试验和示范资料建立的计算机测土施肥模型综合考虑了土壤中各种营养元素的综合平衡和土壤对磷、钾的吸附固定能力。     

用于表征三七种植区土壤中可利用态砷的化学提取剂的筛选

为正确表征云南文山三七种植区土壤中植物可利用态砷,选取NaH2PO4（0.5mol·L-1）、H2O、H3PO4（0.2mol·L-1）、EDTA（0.0625mol·L-1,pH=7）、NH4C（l1.0mol·L-1）和（NH4）2SO（40.05mol·L-1）6种提取剂,比较了它们对土壤中砷的提取效果,及其所提取的砷与三七植株各部位砷含量之间的相关关系。结果表明,NaH2PO4、H3PO4和（NH4）2SO4这3种提取态砷与土壤总砷呈极显著正相关,相关系数分别为0.8359、0.8177和0.8810。NaH2PO4和H3PO4的提取效率较高,平均提取效率分别为6%和11%;而（NH4）2SO4提取效率较低,平均仅为0.084%。NaH2PO4和（NH4）2SO4提取态砷与三七主根、须根和茎部砷含量呈显著正相关,H3PO4提取态砷与三七主根和须根砷含量呈显著正相关。综合考虑认为NaH2PO（40.5mol·L-1）是最佳提取剂,H3PO（40.2mol·L-1）提取剂次之,这两种提取剂均可较好地表征土壤中砷的三七可利用性。     

动力学模型在土壤钾素释放特征描述中的运用及其与化学方法提取的钾素之间的相关性研究

Potassium (K) release characteristics in soil play a significant role in supplying available K. Information on K-release characteristics in soils of central Iran is limited. The objectives of this study were to determine K release characteristics and correlations of K release rate constants with K extracted by different chemical methods in surface soils of ten calcareous soils of central Iran. The kinetics of K release in the soils was determined by successive extraction with 0.01 mol L^-1 CaCl₂ in a period of 2--2 017 h at 25±1 ^oC. Soil K was extracted by distilled water, 0.5 mol L-1 MgNO₃, 0.002 mol L^-1 SrCl₂, 0.1 mol L^-1 BaCl₂, 0.01 mol L^-1 CaCl₂, 1 mol L^-1 NaCl, 1 mol L^-1 boiling HNO₃, 1 mol L^-1 NH₄OAC, Mehlich 1, 0.002 mol L^-1 SrCl₂ 0.05 mol L^-1 citric acid, and ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA). A plot of cumulative amounts of K released showed a discontinuity in slope at 168 h. Thus, two equations were applied to two segments of the total reaction time (2--168 and 168--2017 h). Cumulative amounts of K released ranged from 55 to 299 mg kg^-1 in 2--168 h and from 44 to 119 mg kg^-1 in 168--2 017 h. Release kinetics of K in the two time segments conformed fairly well to parabolic diffusion, simplified Elovich, and power function models. There was a wide variation in the K release rate constants. Increasingly higher average concentrations of soil K were extracted by distilled water, Mehlich 1, SrCl₂, CaCl₂, SrCl₂ + citric acid, AB-DTPA, MgNO₃, NaCl, NH₄OAc, BaCl₂ and HNO₃. Potassium release rate constants were significantly correlated with K extracted. The results of this study showed that information obtained from mathematical modeling in two reaction time segments can help to estimate the K-supplying power of soils.