The examination of humic substances in soils and composts with high organic content with different methods

The organic materials, especially the complex structural humic substances are acid-characteristic polymers which are key elements of soils. Despite their relatively small quantity, humic substances have beneficial effects on soil nutrient management, development of optimal soil structure, regulation of soil temperature, and proper water management. The application of the UV-VIS spectrophotometry for describing humic substances in soils and determining of humifical state is nowadays a widespread method. The E4/E6 procedure (which were determined between 465 and 665 nm wavelength) and the Hargitai-method (the extinction of extracts measured between 400 and 750 nm at 9 wavelength) are procedures that have become the general tool for determining the quality of humic matters because of its easy accessibility and smaller need of instrumentations. Nevertheless, their usefulness has been criticized in scientific communities because of the high human error factor and the technical limitations of the simpler spectrophotometric instruments. Nowadays the spreading light scattering photometric examinations using lasers as the Static Light Scattering (SLS) or the Dynamic Light Scattering (DLS) could be a new way of measuring the quality of the humic matters. This study is based on the examination of different quality soil and compost samples which were extracted from different Hungarian sites like Trizs, Szárítópuszta and Csobánc. Additionally, not only the soils and composts were analyzed but also any soil conditioners (biochar, bone charcoal) which were applied and affected their properties. The main goal of the research was to measure the soil and compost samples with the E4/E6 and the Hargitai-method and with also using Zetasizer Nano ZS device that could lead to more detailed results about the weight and the size of the humic molecules. Based on the summarized analytic results the outcomes of the E4/E6 procedure is applicable for drawing relevant conclusion regarding the humic quality of the given sample. On the contrary, the applied Hargitai-method has not proved to be effective. Although the measurement of the molecule’s size and weight with the Zetasizer Nano ZS device has brought out exciting results and displayed similarities with the E4/E6 outcomes, only it’s tendencies proved to be informative because of its methodological background. &nbsp

Monitoring the degradation of partly decomposable plastic foils

Abstract We have monitored the behaviour of different polyethylene foils including virgin medium density polyethylene (MDPE), MDPE containing pro-oxydative additives (238, 242) and MDPE with pro-oxydative additives and thermoplastic starch (297) in the soil for a period of one year. A foil based on a blend of polyester and polylactic acid (BASF Ecovio) served as degradable control. The experiment was carried out by weekly measurements of conductivity and capacity of the soil, since the setup was analogous to a condenser, of which the insulating layer was the foil itself. The twelve replications allowed monthly sampling; the specimen taken out from the soil each month were tested visually for thickness, mechanical properties, morphological and structural changes, and molecular mass. Based on the obtained capacity values, we found that among the polyethylene foils, the one that contained thermoplastic starch extenuated the most. This foil had the greatest decrease in tensile strength and elongation at break due to the presence of thermoplastic starch. The starch can completely degrade in the soil; thus, the foil had cracks and pores. The polyethylene foils that contained pro-oxydant additives showed smaller external change compared to the virgin foil, since there was no available UV radiation and oxygen for their degradation. The smallest change occurred in the virgin polyethylene foil. Among the five examined samples, the commercially available BASF foil showed the largest extenuation and external change, and it deteriorated the most in the soil.</jats:p

The examination of humic substances in soils and composts with high organic content with different methods

The organic materials, especially the complex structural humic substances are acid-characteristic polymers which are key elements of soils. Despite their relatively small quantity, humic substances have beneficial effects on soil nutrient management, development of optimal soil structure, regulation of soil temperature, and proper water management. The application of the UV-VIS spectrophotometry for describing humic substances in soils and determining of humifical state is nowadays a widespread method. The E4/E6 procedure (which were determined between 465 and 665 nm wavelength) and the Hargitai-method (the extinction of extracts measured between 400 and 750 nm at 9 wavelength) are procedures that have become the general tool for determining the quality of humic matters because of its easy accessibility and smaller need of instrumentations. Nevertheless, their usefulness has been criticized in scientific communities because of the high human error factor and the technical limitations of the simpler spectrophotometric instruments. Nowadays the spreading light scattering photometric examinations using lasers as the Static Light Scattering (SLS) or the Dynamic Light Scattering (DLS) could be a new way of measuring the quality of the humic matters. This study is based on the examination of different quality soil and compost samples which were extracted from different Hungarian sites like Trizs, Szárítópuszta and Csobánc. Additionally, not only the soils and composts were analyzed but also any soil conditioners (biochar, bone charcoal) which were applied and affected their properties. The main goal of the research was to measure the soil and compost samples with the E4/E6 and the Hargitaimethod and with also using Zetasizer Nano ZS device that could lead to more detailed results about the weight and the size of the humic molecules. Based on the summarized analytic results the outcomes of the E4/E6 procedure is applicable for drawing relevant conclusion regarding the humic quality of the given sample. On the contrary, the applied Hargitaimethod has not proved to be effective. Although the measurement of the molecule’s size and weight with the Zetasizer Nano ZS device has brought out exciting results and displayed similarities with the E4/E6 outcomes, only it’s tendencies proved to be informative because of its methodological background

Behavior of Polyethylene Films in Soil

A true-to life experiment on the behaviour of polyethylene films in soil was carried out. Commercial middle density polyethylene (MDPE) film, MDPE films containing pro-oxidative additives and thermoplastic starch and a commercially available biodegradable film (Ecovio, BASF) have been buried in soil and monitored monthly for one year. Bags made out of the films were filled with and surrounded with brown forest soil and electrodes were put into the soil inside the bag and into the soil surrounding the bag. The soil served as capacitor. Degradation could be monitored weekly by measuring the capacity and conductivity of the soil without removing the bags from it. Visual, mechanical (Instron), structural (FTIR, ESR) and morphological (POM, SEM) changes in the films and the change in molecular mass were tested monthly. The polyethylene films suffered only some physical degradation and not biodegradation. Our life-like experiments suggest that biopacking will be the future of plastics waste disposal

Behavior of Polyethylene Films in Soil

A true-to life experiment on the behaviour of polyethylene films in soil was carried out. Commercial middle density polyethylene (MDPE) film, MDPE films containing pro-oxidative additives and thermoplastic starch and a commercially available biodegradable film (Ecovio, BASF) have been buried in soil and monitored monthly for one year. Bags made out of the films were filled with and surrounded with brown forest soil and electrodes were put into the soil inside the bag and into the soil surrounding the bag. The soil served as capacitor. Degradation could be monitored weekly by measuring the capacity and conductivity of the soil without removing the bags from it. Visual, mechanical (Instron), structural (FTIR, ESR) and morphological (POM, SEM) changes in the films and the change in molecular mass were tested monthly. The polyethylene films suffered only some physical degradation and not biodegradation. Our life-like experiments suggest that biopacking will be the future of plastics waste disposal