Hybridspecific nutrient interactions and their role in maize yield quality

C. Bojtor¹*, Á. Illés¹, É. Horváth¹, J. Nagy¹ and L.C. Marton¹²

¹University of Debrecen, Faculty of Agricultural and Food Sciences and Environmental Management, Institute of Land Use, Engineering and Precision Farming Technology 138 Böszörményi St, H-4032 Debrecen, Hungary
²Eötvös Loránd Research Network, Centre for Agricultural Research, Agricultural Institute, 2 Brunszvik St, H-2462 Martonvásár, Hungary
*Correspondence: bojtor.csaba@agr.unideb.hu

Abstract:

Different fertilization levels can be used according to the intensity of the plant production technology. The interactions among all the essential nutrients, the different ways of antagonisms and synergisms can weaken or strengthen the physiological processes of the plants, affecting significantly the efficiency of the production. Complex mineral profile of the vegetative (stalk, leaves) at V2, V4, V8, VT and R6 stages in 4 replications and generative (grain, cob -R6 stage only) plant parts of maize were determined in accredited laboratory with ICP-MS, ICP-OES microwave-assisted multielement analysis for metal components (P, K, mg, Ca, S, Zn, Fe, Cu, Mn, Ni, Mo) and Dumas method for nitrogen. Results showed that the effect of different nitrogen fertilization levels was significant on grain yield, protein, oil and moisture content. Significant differences were measured between the different maize genotypes in grain yield, protein and starch content. In the experiment all essential nutrient concentrations were measured, and the important nutrient ratios of macro- and micronutrients for the physiological development of maize were calculated. These nutrient stoichiometric ratios were evaluated according to their scale of influence in the yield formation. It can be concluded that different nitrogen fertilization levels affected significantly the essential nutrient ratios of the vegetative and generative plant parts of three maize hybrids in the growth period. Although different variables of nutrient stoichiometric ratios and yield parameters did not highly correlated, Pearson’s correlations suggest that K:Mg and K:Zn ratio of stalk would be related with grain yield (R = 0.32; 0.34; 0.39 and 0.35; 0.37; 0.30, respectively) marking them as important parameters for novel nutrient stoichiometry research. Analysing the optimal nutrient ratios related to the yield quality and their interaction with the fertilization practices can give certain recommendations to the farmers to implement hybrid- and site-specific nutrient management strategies, reducing the environmental impact of the over-fertilization.

Key words:

fertilization efficiency, macronutrients, nitrogen use; nutrient ratios, stoichiometry

Energy valorisation of citrus peel waste by torrefaction treatment

B. Tamelová*, J. Malaťák and J. Velebil

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamycka 129, CZ165 21 Prague, Czech Republic
*Correspondence: tamelova@tf.czu.cz

Abstract:

The article deals with the issue of processing and utilization of citrus peel, which often ends unused with other biodegradable waste. The research is concerned with the energy potential of this raw material and its torrefaction conversion. The tested materials were orange peel (Citrus sinensis Osbeck cv ‘Valencia’, Citrus sinensis Osbeck cv ‘Murcia’) and grapefruit peel (Citrus paradise ‘Ruby red’). Samples of dried materials underwent torrefaction treatment at 225 °C, 250 °C and 275 °C for 30 minutes. Samples before and after torrefaction were analysed for proximate and elemental composition and for calorific value. Consequently, stoichiometric combustion analyses were done. The torrefaction was performed in a LECO TGA 701 thermogravimetric analyzer under nitrogen atmosphere. The results of proximate and elemental analysis showed positive influence of torrefaction on the samples. The highest net calorific value for orange peel is 24.97 MJ kg^-1 at the temperature of 275 °C. The greatest differences in net calorific values are between 225 °C and 250 °C where the increase is almost 3 MJ kg^-1. Subsequently, the increase between the 250 °C and 275 °C torrefaction temperatures is 1 MJ kg^-1. Weight loss at respective torrefaction temperatures showed similar time-dependent curves for all samples. Stoichiometric combustion analysis shows slight differences between original samples, but great differences after torrefaction processing. Stoichiometric combustion parameters also change proportionately with increasing temperature of torrefication. The resulting comnbustion balance figures show significantly lower need for mass of fuel in the case of the torrefied material for a given heat output thanks to the net calorific value being nearly doubled.

Key words: