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dc.contributor.advisorCuello, Joel L.en_US
dc.contributor.authorOno, Eiichi
dc.creatorOno, Eiichien_US
dc.date.accessioned2013-04-11T08:39:43Z
dc.date.available2013-04-11T08:39:43Z
dc.date.issued2001en_US
dc.identifier.urihttp://hdl.handle.net/10150/279921
dc.description.abstractMonitoring the nutrient dynamics in the nutrient solutions of hydroponically-grown sweetpotato plants gave the following results. (1) Monitoring the concentrations of critical individual chemical species over time in the hydroponic solution would allow for optimal nutrient management: (a) While the time variation in the Electrical Conductivity (EC) level of a hydroponic solution could suggest normal nutrient uptake, nitrate uptake inhibition, or increased nitrate uptake, the time variation in EC levels could not identify which specific nutrient species were being inhibited or increased in their uptake; (b) Even when the total nitrate assimilation per plant increased over time, the specific nitrate uptake over time actually decreased significantly and correlated well with the saturation of average growth rate, justifying the addition of nitrogen in the solution to achieve optimal growth during the plant's vegetative phase; (c) Doubled-N by ammonium resulted in the significant suppression of the uptake of nitrate and potassium as well as calcium, phosphorus, magnesium, iron and boron, among others; (d) Under doubled-N by nitrate, approximately twice as much nitrate was taken up from the solution relative to the control, indicating that the uptake of nitrate was nitrate-concentration-dependent; (e) Under doubled-N by nitrate, the uptake of potassium was unaffected; and (f) Doubled-K, designed to initiate sweetpotato rooting, significantly suppressed nitrate uptake as desired and kept the potassium uptake unaffected. (2) The fairly reasonable regularity of time variation of EC level and nutrient uptake would allow for mathematical modeling, useful for biomass prediction and stress diagnostics: (a) EC modeling over time by exponential fits resulted in reasonably acceptable r-squares under doubled-N by nitrate treatment and the control condition; (b) EC changes in the standard solution provided reasonable inverse correlation with the plant's average growth rate; (c) Exponential fitting of nitrate concentrations over time resulted in reasonable r-squares both for the doubled-N by nitrate treatment and the control condition; and (d) Under the doubled-K treatment, nitrate uptake was significantly suppressed, so that the resulting variation in nitrate concentration over time deviated significantly from that for the control condition or even that for the doubled-N by nitrate treatment, indicating physiological stress for the plants.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectAgriculture, Plant Culture.en_US
dc.subjectEngineering, Agricultural.en_US
dc.titleMonitoring of nutrient solution for hydroponically grown sweetpotato (Ipomoea batatas)en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest3040134en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAgricultural & Biosystems Engineeringen_US
thesis.degree.namePh.D.en_US
dc.identifier.bibrecord.b42481880en_US
refterms.dateFOA2018-08-16T09:01:50Z
html.description.abstractMonitoring the nutrient dynamics in the nutrient solutions of hydroponically-grown sweetpotato plants gave the following results. (1) Monitoring the concentrations of critical individual chemical species over time in the hydroponic solution would allow for optimal nutrient management: (a) While the time variation in the Electrical Conductivity (EC) level of a hydroponic solution could suggest normal nutrient uptake, nitrate uptake inhibition, or increased nitrate uptake, the time variation in EC levels could not identify which specific nutrient species were being inhibited or increased in their uptake; (b) Even when the total nitrate assimilation per plant increased over time, the specific nitrate uptake over time actually decreased significantly and correlated well with the saturation of average growth rate, justifying the addition of nitrogen in the solution to achieve optimal growth during the plant's vegetative phase; (c) Doubled-N by ammonium resulted in the significant suppression of the uptake of nitrate and potassium as well as calcium, phosphorus, magnesium, iron and boron, among others; (d) Under doubled-N by nitrate, approximately twice as much nitrate was taken up from the solution relative to the control, indicating that the uptake of nitrate was nitrate-concentration-dependent; (e) Under doubled-N by nitrate, the uptake of potassium was unaffected; and (f) Doubled-K, designed to initiate sweetpotato rooting, significantly suppressed nitrate uptake as desired and kept the potassium uptake unaffected. (2) The fairly reasonable regularity of time variation of EC level and nutrient uptake would allow for mathematical modeling, useful for biomass prediction and stress diagnostics: (a) EC modeling over time by exponential fits resulted in reasonably acceptable r-squares under doubled-N by nitrate treatment and the control condition; (b) EC changes in the standard solution provided reasonable inverse correlation with the plant's average growth rate; (c) Exponential fitting of nitrate concentrations over time resulted in reasonable r-squares both for the doubled-N by nitrate treatment and the control condition; and (d) Under the doubled-K treatment, nitrate uptake was significantly suppressed, so that the resulting variation in nitrate concentration over time deviated significantly from that for the control condition or even that for the doubled-N by nitrate treatment, indicating physiological stress for the plants.


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