Cezary Kwiatkowski

Surface Properties of Aerated Ion-induced Whey Protein Gels

Aerated whey protein gels were formed using calcium chloride, magnesium chloride or iron (II) chloride induced gelation of pre-denatured protein dispersions. The structure of the obtained gel surface depends on the type and concentration of added salt. Higher cation concentration produced gels a with higher quadratic mean of the surface roughness and maximum roughness height. Aerated gels of optimal properties for retaining air bubbles were characterized by similar surface roughness. The surface topography is mainly responsible for changes in the wettability. The contact angle of the probe liquid sample depends on the liquid surface tension components. An approach based on the contact angle hysteresis (CAH) is suitable for determining the total value of the apparent surface free energy of such materials. An approach based on the components of apparent surface free energy (LWAB) only allows the calculation of the dispersion component and electron donor parameter of energy in the case of added magnesium and iron salt. Wettability, depending on the nature of the surface, can be described for the hydrophilic surface by the Wenzel model, and for the hydrophobic surface by the Cassie – Baxter model.

Cover cropping influences physico-chemical soil properties under direct drilling soybean

In seeking effective methods to prevent soil degradation, conservation tillage plays an important protective role. Apart from significantly reducing production costs, cover crops contributes to beneficial changes in the soil environment. A three-year field experiment included three cover crops (winter rye, winter oilseed rape, and white mustard) subjected to mulching or desiccation and to the action of a herbicide at three rates (100%, 75%, and 50%). The study evaluated soil moisture and the content of organic matter, phosphorus, potassium, and magnesium in two soil layers (0–15 cm and 15–30 cm). Cover cropping had a positive effect on soil organic matter content. More organic matter (by 4.7%) was recorded in the topsoil layer (0–15 cm). Among the cover crops most favorable effect on the content of organic matter in the soil had white mustard (an increase of 14.2%) compared to the control. Moreover, rye and white mustard mulch increased the soil content of phosphorus and magnesium, while oilseed rape mulch increased the potassium content. At the critical growth stages (the flowering/pod set) of soybean (Glycine max (L.) Merril), soil moisture was dependent on mulching treatment and soil layers.

Biochemical changes in the recreational areas soil caused by the intensity of use

The aim of this study was to determine the effect of the intensity of selected recreational areas use on biochemical changes within soils. Soil samples were collected from different playgrounds, playing fields and horse farms. Granulometric composition of the soils was determined. Heavy metals concentration, organic carbon concentration, total nitrogen concentration and activities of dehydrogenases, phosphatase and urease were measured at unburdened and burdened sites of the investigated recreational areas. It was found, that the use of the recreations areas triggers the changes in biochemical composition of the soil. Greater burden decreases the enzymes concentration in the soil. For most sites, a positive correlation was found between enzymes and organic carbon concentration and between phosphatase and urease. The degree of heavy metals soils contamination was low and only the samples from one playing field and one horse farm had increased concentration of cadmium. Monitoring of biochemical changes in recreational areas soil (especially playgrounds) is very important to provide safe environment for human leisure time.

Intensywność mechanicznych zabiegów pielęgnacyjnych a zasób nasion chwastów w glebie [The intensity of mechanical cultivation measures vs. the amount of weed seeds in the soil]

The effect of the number of mechanical operations in sugar beets plantation on the amount and species composition of weed seeds in the 0–5 cm deep layer of the loessial soil was studied. It has been proved that reduction in the number of weed seeds depends upon both the frequency of weeding-out operations and the level of agrotechnic. The highest decrease in the number of fruit and weed seeds was caused by eightfold weed removal which took place during the period from emergence phase to the joining of sugar beet rows. Application of increased mineral fertilization, microelements, fungicides, and insecticides caused the number of weed seeds to be reduced by 5,9%, in comparison to extensive agrotechnical level.