Description succincte
(Anglais)
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This project will evaluate whether animal manure, when added at agronomically relevant levels, can contribute to increase Zn concentration in wheat grain without affecting mineral pollutants contents. This proposal is composed of two outputs. In the 1st output we will evaluate the fluxes of Zn from manure to wheat grain and in the 2nd output we will evaluate the use-fulness of measuring the natural abundance of 66Zn ( 66Zn) in fertilizer, soil and plant to assess the source of Zn and the mechanism of Zn uptake by wheat. This research will be carried out by a PhD student of the Group of Plant Nutrition of the ETH Zurich in close collaboration with the groups of Soil Protection and of Human Nutrition of the ETH, the Swiss Re-search Institute of Organic Agriculture (FiBL, Frick Switzerland), the Sant'Anna School of Advanced Studies in Pisa (Italy), and the Paul Scherrer Institute (Villingen, Switzerland). This project will contribute to the fulfillments of 3 deliverables de-fined for the working group 1 in the memorandum of understanding of the COST action FA-0905: improve Zn fertilization efficiency, study soil and plant factors affecting Zn uptake by roots and its accumulation in grains, and develop isotopic techniques to assess Zn fluxes and Zn uptake processes.
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Partenaires et organisations internationales
(Anglais)
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AT, BE, BG, CH, CZ, DE, DK, EL, ES, FI, FR, HU, IL, IT, LT, LU, NL, NO, PL, PT, RO, RS, SE, SI, SK, TR, UK
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Résumé des résultats (Abstract)
(Anglais)
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Micronutrient malnutrition, also known as “hidden hunger“, receives increasing attention from important world organizations (WHO, UNICEF, FAO) because of its impact on a significant proportion ofthe world population. Zinc (Zn) is an essential micronutrient for all living organisms. lt has structural and functional roles in metalloenzymes, biomembranes, transcription processes and gene expression. The first cause ofZn deficiency in human nutrition is inadequate dietary intake of bioavailable Zn. Populations living in regions where the daily calorific intake is mostly based on cereals are particularly exposed to Zn deficiency. lncreasing the Zn content in the edible part of crops might contribute to alleviate the problem of Zn deficiency in human nutrition. Low Zn content in crops can be linked to two major causes: i) bw Zn content of the soll and ii) bw phytoavailable Zn in the soll. The present project is investigating the impact of fertilization strategies, with emphasis on organic fertilizers, on the Zn transfer from the soil to the plant. On the one hand organic fertilizers can be considered as an important Zn source (direct effect), and on the other they can change the phytoavailability of zinc by changing the physicochemical and biobogical properties ofthe soll (indirect effect). The first objective ofthis project is to determine the effect of different organic fertilizer inputs on the phytoavailability ofZn in agricultural soils. The second objective is to evaluate and to improve isotopic techniques in order to identify and to quantify the effects of organic fertilizer inputs on plant Zn uptake. To our knowledge the second objective is addressed for the first time. In the first part of the project, the effect of different fertilization strategies on the soil and crop Zn status were investigated in three long-term field trials. Two proxies were used to estimate the phytoavailable Zn of the soll: DTPA-extractable Zn and Diffusion Gradients in Thin films (DGT). In both cases the resuits indicated a Zn depletion by crop export in pure mineral fertilized treatments. In the treatments where organic fertilizers were applied the results showed a neutral or positive Zn-balance. The Zn content in grain and straw was not affected by the Zn-inputs because the investigated soils did not show severe Zn-deficiency. In such non-deficient conditions, the Zn-content of the plants is mainly driven by homeostasis. In the second Part of the project isotopic tracer techniques were used to validate the indirect spiking approach stable Zn isotopes. The indirect approach is necessary to trace Zn derived from organic fertilizers, which are difficult to spike intrinsically with isotopes. Because of experimental difficulties, lt is not yet possible to definitively confirm the accuracy of this method. However, the results of a pre-experiment predict a positive outcome. The large amount samples produced in two pot experiments were used to optimize the experime
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