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Title: A study of the effects of potassium chloride and sulphate on the uptake of nutrients by ryegrass, from soil, using radioactive isotopes of iron
Author: John, Reginald S.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1970
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1. Review of the literature indicated that at low levels of potassium iron chlorosis may result in plants either from reduced uptake or from iausobllization within tissues. This condition is intensified by high levels of calcium but the influence of other ions, especially chloride and sulphate is less clear. 2. Experimental techniques in plant nutrition studies were reviewed and an analytical system was devised for determination of N, P, K, Ca, Mg and Fe in a single digest of dried plant tissue. 3. Techniques for radioactive studies were reviewed and direct solid scintillation counting of Fe in soils and plant material was 55 adoptee, using a Mairell crystal for the latter. For incomparable amounts the radiation intensities proved too lor for quantitative estimation with the available equipment, dcspit' concentration of iron in plant tissue digests by co-prccipitation with Mg(GH)p. 4. Two pot experiments were conducted respectively with Italian ryegrass and New Zealand hybrid to test the effect of four levels of potassium ranging from 2-16 me potassium as sulphate and chloride, on the uptake of Fe and K, and also N, P, Hg and Ca. Soil labelled either with Fe or Fe was used in the upper, middle or lower third of each pot to study the effect of rooting habit and soil depth on Fe uptake. 5. For both species and three successive cuts the Fe content was not influenced by chloride or sulphate, but sulphate increased N and Ar contents and decreased Ca content. Chloride increased K and P contents only in Italian ryegrass. Sulphate gave higher dry matter yields in both species and source effects on nutrient untake depended raninly on this. Increased K level generally depressed Fe content but consistently increased K content. Maximum dry matter yields were at 8 nie.K. 6. Fe uptake d-crossed with soil depth in sympathy with root intensity. For both species K content decreased and Mg content increased vith labelled depth whereas N was unaffected and, Ca and P showed variable effects. Radiation damage to roots was not evident. The apparent differential effects of labelling on nutrient content were probably indirect, due to the chelating agent DTP A used for labelling soil.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available