richards方程在描述包膜控释肥料氮素释放特征中运用

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1、9期喻建刚等：Richards方程在描述包膜控释肥料氮素释放特征中的运用5Richards方程在描述包膜控释肥料氮素释放特征中的运用喻建刚，樊小林，李宁，刘芳（华南农业大学资源与环境学院肥料与平衡施肥研究室，广州510642）摘要：【目的】筛选适合于描述控释肥料氮素释放特征的数学模型，为以数学模型预测预报控释肥料供肥特征提供理论依据。【方法】运用Richards,Logistic和Bertalanffy方程拟合在(25±0.5)℃恒温条件下包膜控释肥料在静态水中的氮素累积释放曲线。【结果】结果表明Richards函数能较好地拟合不

2、同形状的氮素养分累积释放曲线，其拟合度优于通用的Bertalanffy和Logistic方程。3种方程中，Richards方程的特征参数更能精确地描述包膜控释肥料氮素释放特征，能反映出氮素养分最大释放速率出现的时间、累积释放曲线的形状等。【结论】Richards方程可用于拟合S型、抛物线型和双抛物线型3种类型的养分释放曲线；增加包膜厚度能降低控释肥料氮素养分在水中前期的溶出率，同时推迟最大养分释放速率出现的时间。关键词：Richards方程；包膜复合肥料（控释肥料）；氮素释放；释放曲线特征ApplicationoftheRicha

3、rdsEquationtoDescribeNitrogenReleaseCharacteristicsfromControlledReleaseFertilizer(CRF)YUJian-gang,FANXiao-lin,LINing,LIUFang(ResearchLaboratoryofFertilizerScienceandBalancedFertilization,CollegeofNatureResourceandEnvironmentScience,SouthChinaAgriculturalUniversity,Gu

4、angzhou510642)Abstract：【ObjectiveandMethod】InordertoselectasuitableequationtodescribenitrogenreleaseandamathematicmodeltopredictnutrientreleasefromCRF,theRichards,BertalanffyandLogisticequationswereappliedtomodelnitrogenreleasefromcoatedNPKfertilizersascontrolledrelea

5、sefertilizerinstaticwaterunderaconstanttemperatureof(25±0.5)℃.【Result】TheresultshowedthattheRichardsequationwasappliedtodescribetheprecisenitrogenreleasecurveofadifferenttype.TheRichardsequationwassuperiortoBertalanffyandLogistic.Amongthethreeequations,thecharacterist

6、icsoftheRichardsequationexpressedthenitrogenreleaseproperty,thetimetothepointatwhichthemaximumamountreleasedperunittimeandtheshapeofthereleasecurveofthecoatedNPKfertilizer.【Conclusion】Insummary,theRichardsequationfitsmodelsofthreetypesofnutrientreleasecurves,including

7、thesigmoidpattern,parabolicpatternanddoubleparabolicpattern.InusingbothparametersdandtiinRichardsequation,onecaneasilyjudgemodelofnutrientsreleasecurve.IncreasingcoatingthicknesscoulddecreasenitrogenreleaseratefromCRFatearlyperiodofincubationanddelaythetimeformaximumr

8、eleaseofnutrientfromCRF.Keywords:Richardsequation;CoatedNPKfertilizer（CRF）;Nitrogenrelease;Characteristicsofreleasecurve9期喻建