No abstract

Long term productivity and conservation of soils is critical for sustaining agricultural ecosystems. The specific objective of the work reported was to determine the effects of long term application of organic and mineral fertilizers on soil enzyme activity as an index of soil biology and biochemistry. Three key soil enzymes involved in intracellular metabolism of microorganisms and two soil enzymes involved in phosphorus metabolism were selected. Actual and potential dehydrogenase, catalase, acid and alkaline phosphatase activities were determined in the 0-20 cm layer of an eroded soil submitted to a complex fertilization experiment. Results showed that addition of mineral fertilizers to organic (green manure and farmyard manure) fertilizers led to a significant increase in each activity because of increased plant biomass production which upon incorporation stimulates soil biological activity. The enzymatic indicators of soil quality calculated from the values of enzymatic activities depending on the kind of fertilizers showed that by the determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. A weak positive correlation between enzymatic indicators of soil quality and maize yield was established. The yield data demonstrate the superiority of farmyard manure which provided greater stability in crop production. Substantial improvement in soil biological activity due to application of organic fertilizers with mineral fertilizers contribute in maintaining the productivity and soil health.

Soil enzymes activities have been considered as sensitive indicators of alteration soil quality by management. In order to obtain new data on the soil enzymological effects of soil management practices, we have determined some enzymatic activities in a preluvosoil submitted to a complex tillage and crop rotation experiment at the Agricultural Research and Development Station in Oradea (Bihor County). Actual and potential dehydrogenase, acid phosphatase and catalase activities were investigated in a split plot experiment where tillage (no-till and conventional tillage) was the main plot and crop rotation (Wheat/Maize, W/M; Soybean/Maize, S/M; Oats-Clover/maize, O-C/M) was the subplot. Soil samples were taken at 0-20, 20-40 and 40-60 cm. Each activity in both non-tilled and conventionally tilled soil under maize crop decreased with increasing sampling depth. It was found that no-till, in comparison with conventional tillage, resulted in insignificantly higher (p]0.10) soil enzymatic activities in the 0-20 cm layer and insignificantly (at least at p]0.10) lower activities in the deeper layers, excepting actual and potential dehydrogenase activities in the 40-60 cm layer, in which these activities were significantly lower(0.02]p]0.01). Based on the absolute values of the enzymatic activities, the enzymatic indicator of soil quality (EISQ) was calculated. The EISQ values ranged between 0.201 and 0.974 indicating the presence of high enzymatic activities in the upper layer and a moderate intensity of the enzymatic activities in the deeper layers. A significant correlation between soil enzyme activities and physical and chemical indicators was established.

No abstract

Grape skin is considered a valuable by-product for antioxidant and antibacterial agent preparation. The grape skin contains some active compounds, such as, dietary fiber, polyphenols, flavonols, and resveratrol; it is commonly used as a nutritional supplement. The main aim of this study was to establish the optimum dose of grape skin flour, to be used as a functional ingredient in the bakery products industry, from both chemical and rheological point of view. The laboratory experiments evaluated the functional potential of wheat flour enriched with grape skin flour, in different proportions, by examining the chemical composition and rheological behaviour of the doughs. Protein, crude fibre, fat, ash and mineral contents were determined. Using �H-NMR spectral technique, the fatty acids composition was determined, especially the concentrations of short-chain saturated fatty acids (C4-C8), di-unsaturated fatty acids, mono-unsaturated fatty acids and long-chain saturated fatty acids (]C8). 1H-NMR spectra were recorded on a Bruker Ascend 400 MHz spectrometer. The rheological behaviour was analyzed using the predefined Chopin + protocol on Mixolab, an equipment of CHOPIN Technologies. Grape skin flour was incorporated into wheat flour at three different levels, 5, 10 and 15% and it was found that incorporation up to a 15% level into the formulation of wheat flour yielded an acceptable product in terms of rheological parameters, with improved chemical, nutritional and functional properties.