简介:研究了单质硫对碱性植烟土壤pH值及烤烟产质量影响,结果表明:施用单质硫可明显降低土壤pH值,随单质硫施用量愈大,降低幅度愈大,土壤碱解氮、速效磷、速效钾含量增加,有机质含量变化不明显,但容重有增加的趋势;施用单质硫不影响烟株前期发育,而影响成熟期,随单质硫施用量增加,株高增高,茎围增粗,适量(300~600kg/hm^2)单质硫处理,烟株农艺性状较好。烟叶的经济性状较好;施用单质硫有利于烟叶钾含量的提高,施用300kg/hm^2单质硫烟叶评吸质量较好;综合单质硫降土壤pH值效果及烟叶生长、农艺性状、产质量情况,在豫中碱性植烟土壤环境,建议单质硫施用量为300kg/hm^2。
简介:Monoammoniumphosphate(1molL^-1),monopotassiumphosphate(1molL^-1)andaluminumchloride(5×10^-3molL^-1)wereusedtoinvestigatetheinfluenceofpHontheformationofNH4-taranakiteandK-taranakiteinsystemswithahighNH4H2PO4orKH2PO4concentration.TheexperimentaldataindicatedthatthereactionproductsofaluminumwithNH4H2PO4orKH2PO4changedwiththepHinthesystems.InapHrangeof2.5to10.0,asthepHincreased,theproductsineitherammoniumorpotassiumsystemfollowedthesequence:taranakite,amorphous(NH4,K)2AIH(PO4)2.4H2O,andthencrystalline(NH4,K)AlPO4OH.2H2O.However,thepHrangesoftheformationoftheseproductsinammoniumsystemweredifferentfrompotassiumsystem.NH4-taranakiteformedfrompH2.75topH5.75,whereasK-taranakiteformedinthepHrangeof3.00to5.0,Fromthetheoreticalcalcuationbyacomputerprogram(GEOCHEMversion2.0),NH4-taranakteandK-taranakitecouldformatthepHfrom1.50to8.30andfrom1.25to8.45,respectively.ThesepHrangesweremuchwiderthantheexperimentalresults.Thedifferencebetweentheexperimentaldataandtheoreticaldatawasattributedtothelackofkineticdataand/ortheincompletenessandinaccuracyofthethermodynamicdatainthedatabaseoftheprogram.ThepHrangesoftheformationofthetaranakitesindicatedthatthetaranakitescouldexistintheimmediatevicinityofphosphateferilizerzoneasreactionproductsofphosphatefertilizerswithsoils,especiallyacideicsoils,resultinginthefixationofnotonlyphosphatebutalsonitrogenand/orpotassiuminsoils.
简介:TheimpactofpHchangesonmicrobialbiomasscarbon(Cmic)andmicrobialbiomassphosphorus(Pmic)wereexaminedfor3redsoilsundercitrusproductionwithdifferentlengthsofcultivation.SoilpHsignificantlyaffectedCmicandPmic.TheCmicandPmicchanges,asafunctionofsoilpH,appearedtofollowanormaldistributionwiththeoriginalsoilpHvalueattheapexandaspHincreasedordecreasedcomparedtotheoriginalsoilpH,CmicandPmicdeclined.Moreover,therewerecriticalpHvaluesatbothextremes(3.0ontheacidicsideand8.0to8.5onthealkalineside),beyondwhichmostofmicroorganismscouldneversurvive.TheeffectofpHonCmicandPmicwasalsorelatedtotheoriginalsoilpH.ThehighertheoriginalsoilpHwas,thelessCmicorPmicwereaffectedbypHchange.ItissuggestedthatsoilmicroorganismsthatgrowinasoilenvironmentwithamoreneutralsoilpHrange(I.e.pH5.5-7.5)mayhaveagreatertolerancetopHchangesthanthosegrowinginmoreacidicormorealkalinesoilpHconditions.
简介:在modulating植物生产率的土壤pH的潜在的角色根据干燥质量被估计,在0.25m2空铅形式收获了,在北希腊的二块低生产率的高地草地使遭到了到年度因素的氮(N)和磷(P)授精(15gNm−2year−1和10gPm−2year−1)在最小上3年的时期。在这些特别条件下面,一种积极关系将在土壤pH和植物生产率之间存在,进一步,营养素的那N或P化肥应用限制系统,这被假设,将导致一变弱这种积极关系。一种重要积极关系在其它在二个学习区域和一个积极趋势之一在土壤pH和植物生产率之间被证实。而且,植物生产率增加,后面的授精,看起来在土壤pH植物生产率关系上有有害效果。调查结果支持原来的假设并且加强想法种调停差异的土壤pH植物生产率关系是发生在更多的“typical”下面的更强烈的植物种形成的结果更高的pH在的土壤条件与热带区域对比适度。
简介:以大连虾蛄为原料,从肌肉及消化腺中提取消化酶(蛋白酶和淀粉酶),研究其酶学特性。结果表明,大连虾蛄肌肉中蛋白酶最适温度为50℃,最适pH为8,反应激活剂为Mg2+、Ca2+和Mn2+,抑制剂为Pb2+、Cu2+、Zn2+、Fe2+;消化腺中蛋白酶最适温度为40℃,最适pH为6,EDTA对其有抑制作用,反应激活剂为Ca2+和Mn2+,抑制剂为Pb2+、Mg2+、Cu2+、Zn2+、Fe2+;大连虾蛄肌肉中淀粉酶最适温度为30℃,最适pH为7,反应激活剂为Mn2+,在浓度为20mmol/L时,激活作用最大,抑制剂为Pb2+、Mg2+、Ca2+、Cu2+、Zn2+和Fe2+;消化腺中淀粉酶最适温度为30℃,最适pH为7,EDTA对消化腺淀粉酶有抑制作用,反应激活剂为Mn2+和高浓度Ca2+,抑制剂为Pb2+、Mg2+、Cu2+、Zn2+、Fe2+。