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Long-term effects of tillage and fertilization on pH and sorption parameters of haplic Luvisol

100%

Simansky V. , Kovacik P.

tom 20

nr 4

The influence of different tillage and fertilization practices on changes in soil pH and sorptive parameters of loamy haplic Luvisol was evaluated in a long-term field experiment (established in 1994, in the locality of Dolná Malanta, at the experimental station of the Slovak University of Agriculture in Nitra). The field experiment included two types of soil tillage (conventional tillage – CT and reduced tillage – RT) and also three treatments of fertilization (1. Co – control, 2. PR+NPK – crop residues together with added NPK fertilizers, and 3. NPK – with added NPK fertilizers). The soil was sampled from all treatment sites throughout 1994-2011. The results showed a statistically significant influence of tillage and fertilization on pH and sorptive complex of haplic Luvisol. The values of pH were higher (by 4%) in RT than in CT. The sum of basic cations (SBC), cation exchangeable capacity (CEC) and base saturation (BS) were all higher in RT, by 11%, 8% and 3% respectively, than in CT. In NPK (by 16%) and in PR+NPK (by 20%) the values of hydrolytic acidity (Ha) were decreased in comparison to the control. On the other hand, SBC was elevated. This led to the increase of CEC and BS. Conventional tillage and application of crop residues together with NPK fertilizers increased pH by 0.06 and 0.03 units per year, respectively, which means that the pH in the soil increased by14% and 8%, correspondingly, between 1994 and 2011. In CT and in PR+NPK, an increase of SBC occurred at an average rate of 3.17 and 1.93 mmol kg-1 year-1, respectively. A positive correlation between the content of soil organic carbon (TOC) and Ha (r = 0.334, P ≤ 0.01, n = 54), as well as a negative correlation between TOC and BS (r = -0.307, P ≤ 0.05, n = 54) were determined only in CT.

Sorption features of corn and rice crisps

100%

Ruszkowska M. , Ocieczek A. , Palich P.

2008

tom 11

nr 1[156]

Influence of correction values on sorption parameters: case of lead

100%

Diatta J. B.

2002

tom 11

nr 3

Three adsorption equations were applied to verify the influence of correction values (CV) on adsorption parameters calculated using Langmuir, Freundlich and Gunary isotherms. It was found that the inclusion or not of the correction values into the -Langmuir equation did not yield appreciable differences either for amax or b parameters in the case of soils with relatively high organic matter content, cation exchange capacity and neutral pH. For the Freundlich equation, the higher the correction values the lower the partition parameters. Maximum adsorption parameters (amax) calculated from the Gunary equation were proportionally related to correction values. The higher the correction values the higher the amax parameters. On the basis of the current results it seemed that the goodness-of-fit criteria for analytical data to adsorption equations herein applied may be partially related to correction values. Ideally, the sorption studies would be determined in systems in which the surface would be free of the adsorbate ion. Usually this restriction is far not feasible, mainly in soil environment.

Impact of comminution on adsorption properties of gluten-free wheat starch

80%

Ocieczek A.

Acta Agrophysica

2013

tom 20

nr 1

The process of grinding of wheat grain endosperm leads to damage of the starch fraction. Starch damage in wheat flour changes its water absorption. Intact starch absorbs water in the amount of 70% of its mass, and damaged granules have up to 3-fold higher level of absorption, which is conditioned by the increased number of small crystalline structures and damage to many crystalline structures. These changes cause an increase of the volumetric water absorption capacity and it can be assumed that this will be reflected in the surface microstructure of starch particles that affect the adsorption of water vapour. The aim of the study was to evaluate the impact of comminu-tion of gluten-free wheat starch on the adsorption properties of its granules. The study included the determination of adsorption isotherms of water vapour at 20°C with the static-desiccator method and the determination of adsorption parameters and microstructure of starch granule surface based on the GAB and Kelvin equations. The results confirmed the positive impact of mechanical processing on the capacity of surface water vapour adsorption by starch granules and this was indicated by a significantly diversified distribution of adsorption isotherms, surface adsorption parameters and parameters of microstructure of molecules on which adsorption was tested.

Proces rozdrabniania bielma ziarna pszenicy prowadzi do powstawania uszkodzeń frakcji skrobiowej. Uszkodzenie skrobi w mące pszennej powoduje zmiany jej wodochłonności. Skrobia nieuszkodzona absorbuje wodę w ilości 70% swojej masy, a granule uszkodzone wykazują nawet 3-krotnie wyższy poziom absorpcji, co uwarunkowane jest zwiększeniem ilości drobnych struktur krystalicznych oraz uszkodzeniem wielu struktur krystalicznych. Zmiany te wpływają na wzrost zdolności pochłaniania objętościowego wody i zakładać można, że znajdą odzwierciedlenie w mikrostrukturze powierzchniowej cząstek skrobi warunkującej przebieg zjawiska adsorpcji pary wodnej. Celem badania była ocena wpływu rozdrabniania skrobi pszennej bezglutenowej na jej właściwości sorpcyjne. Badanie obejmowało wyznaczenie izoterm sorpcji w temperaturze 20°C metodą statyczno-eksykatorową, określenie parametrów procesu sorpcji i mikrostruktury po-wierzchni granul skrobiowych na podstawie równania GAB oraz równania Kelvina. Otrzymane wyniki potwierdziły dodatni wpływ mechanicznego oddziaływania na zdolność powierzchniowego pochłaniania pary wodnej przez granule skrobiowe, co wykazano poprzez zidentyfikowanie istotnie zróżnicowanego przebiegu izoterm sorpcji, parametrów charakteryzujących pochłanianie powierzchniowe oraz parametrów opisujących mikrostrukturę cząstek, na których sorpcję badano.