Impact of different fertilisers on elemental content in young hybrid aspen stem wood

M. Bertins¹*, A. Bardule², L. Busa¹, A. Viksna¹, D. Lazdina² and L. Ansone-Bertina³

¹University of Latvia, Faculty of Chemistry, Department of Analytical Chemistry, 1 Jelgavas street, LV-1004 Riga, Latvia
²Latvian State Forest Research Institute “Silava”, 111 Rigas street, LV-2169 Salaspils, Latvia
³University of Latvia, Faculty of Geography and Earth Science, Department of Environmental Science, 19 Raina Blvd, LV-1586 Riga, Latvia
*Correspondence: maris.bertins@lu.lv

Abstract:

The biomass production using fast-growing tree species such as hybrid aspen (Populus tremuloides Michx. x Populus tremula L.) has been recognized as an environmentally friendly and cost-effective approach. Growing these species can reduce the negative impact of earlier land mismanagement and at the same time provide additional biomass growth. The application of fertilisers may introduce not only the necessary macro elements (N, P, K) but also significant amounts of toxic heavy metals. Therefore, the knowledge about elemental flows from fertilised soil to the different parts of hybrid aspen trees is essential and especially meaningful for the evaluation of element content in specific environmental ecosystems. The impact of different fertilisers (sewage sludge, digestate and wood ash) on the concentrations of micro- and macro elements in the wood of six-year-old hybrid aspen stands grown on former agricultural land was studied. The determination of element concentrations in different tree rings of hybrid aspen trees was accomplished by inductively coupled plasma mass spectrometry (ICP–MS). Isotope ratio mass spectrometry (IRMS) was used to determine the nitrogen and carbon content and isotope ratios in different parts of hybrid aspen trees. Stem disc samples from hybrid aspen trees were obtained from agricultural land in the central part of Latvia. Samples were taken from six-year-old hybrid aspen trees that at the moment of planting were fertilised with sewage sludge, a residue of biogas production (digestate) and wood ash. The obtained results indicated that the chemical element accumulation in hybrid aspen was affected by the applied fertiliser type. In this study, the use of wood ash, as well as digestate, affected the elemental content in hybrid aspen to a greater extent than the use of sewage sludge, relative to unfertilised (control) subplot. The analysed elements varied in the analysed stem plane (across the tree rings). The most significant changes between the rings were observed for the content of K and Ca.

Key words:

heavy metals, hybrid aspen, ICP-MS, IRMS, macro elements

Content of selected micro and macro elements in dairy cows’ milk in Estonia

M. Malbe¹, T. Otstavel¹, I. Kodis¹ and A. Viitak²

¹Department of Plant Sciences, Estonian Research Institute of Agriculture, Teaduse 13,75501 Saku, Estonia; e-mail: marge.malbe@eria.ee; teet.otstavel@eria.ee; ingrid.kodis@eria.ee
²Department of Chemistry, Faculty of Science, Tallinn University of Technology,Ehitajate tee 5, 19086 Tallinn, Estonia; e-mail: anu.viitak@ttu.ee

Abstract:

Milk and milk products are an important source of dietary minerals for consumers. The content of the micro and macro elements in food varies among and within countries. Information about concentration of micro and macro elements in Estonian food is limited. To get preliminary information about calcium (Ca), magnesium (Mg), selenium (Se), iron (Fe), zinc (Zn), cobalt (Co) and copper (Cu) content in raw milk, samples from 8 Estonian conventional and 2 organic dairy farms, as well as from 2 consumer milks produced by different dairies were analysed by using atomic absorption spectrometry (AAS). No suboptimal micro and macro element concentrations were found in raw milk samples. However, concentration of dietary minerals in consumer milk was lower than the concentration in raw milk except Fe, which was higher in consumer milk.

Key words: