The aim of the study was to determine the shear strength of the soil-root layer obtained as a result of growth of cocksfoot (Dactylis glomerata L.) on degraded soil enriched with the addition of a new zeolite substrate Z-ion. Measurement of shear strength for soil-root layers formed as a result of growth of a grass species (on degraded soil alone and on degraded soil with added Z-ion) was performed in a direct shear apparatus. The measurement results allowed determining parameters of equations describing the dependence of shear strength of studied soil-root layers on normal stress e.g. cohesion and internal friction coefficient. Under the experimental conditions, application of 1% v/v substrate addition to degraded soil induced development of cocksfoot root system which resulted in the significantly increased cohesion of soil-root layer (by 30%) as compared to that formed on degraded soil alone. The enhanced cohesion of the soil-root layer formed on soil enriched with Z-ion resulted in its significantly increased shear strength as compared to that of soil-root layer obtained on soil alone. Further research using higher doses of the Z-ion substrate (greater than 1% v/v) is needed to obtain the information at what dose ranges of the substrate one can expect even more intensive development of plant root systems and, consequently, further significant improvement in the shear strength of the soil-root layers.
Investigations concerned the effect of raising the dose of new Z-ion zeolite substrate on cocksfoot (Dactylis glomerata L.) growth. During the pot experiment, plants were grown on degraded soil, arable soil and mixtures of degraded soil with increasing Z-ion substrate additions (1%, 2%, 5%, 10% v/v). When the experiment was terminated, the mean values of the vegetative parameters of test species were calculated. The carbon to nitrogen ratio for cocksfoot stem biomass was determined. The enzyme diversity of the degraded soil enriched with substrate additions after cocksfoot growth (Shannon’s diversity index) was also evaluated. The application of Z-ion additions positively influenced the cocksfoot growth – the additions in the range of 1–10% v/v to degraded soil significantly increased wet and dry stem biomass, dry root biomass and total dry biomass of plants. It turned out that the Z-ion substrate addition not exceeding 1% v/v can be considered as one which – after introducing into a specific degraded soil – would give similar biomass yield of cocksfoot to that obtained on the selected arable soil. At 1% substrate dose, the carbon/nitrogen ratio in the plant material (27.17) was within the range of values ensuring the proper methane fermentation course. The preliminary studies have shown that a significant increase in enzyme diversity can be observed when there is a certain degree of root development caused by a sufficiently high addition of Z-ion substrate to the degraded soil – under experimental conditions it was 5% v/v Z-ion dose.
The presented study aimed at determining the influence of the increasing dose of new Z-ion zeolite substrate on the growth of maize (Zea mays L.) as species belonging to energy crops. In order to achieve the study aim, the pot experiment was carried out where the plants were grown on six series of media i.e.: on marginal soil (the control series I), on arable soil (the control series II) and on four mixtures of marginal soil with increasing Z-ion substrate addition (1%, 2%, 5%, 10 % v/v). The pot test was carried out in a phytotron with a 13/11 light/dark regime. After the end of the experiment, the mean values of the vegetative parameters (wet and dry biomass of roots and stems) characterizing the plant growth in particular media series were determined. The C:N ratio for maize stems was calculated as well. The obtained study results showed a favorable influence of Z-ion substrate additions on the vegetative growth of maize. Already a 1% (v/v) substrate addition to marginal soil increased the wet and dry stems biomass by 173–204%. At the same time, it turned out that in the sixth week of plant growth, a 5% substrate addition to the marginal soil enables to achieve the value of vegetation parameters at a level similar to that of the parameters characterizing the plant development on arable land. Thus, at an early stage of plant growth, a 5% substrate dose can be considered as one allowing a similar course of maize growing on marginal soil as in the case of arable soil. It is worth noting that at this substrate dose, the C:N ratio in maize stems reached the value of 13.05, at which the plant biomass is the substrate ensuring the fairly proper course of methane fermentation supplying fuel in the form of biogas.
The paper presents the possibility of applying spent synthetic ion exchangers and sorbents based on natural zeolites for the reclamation of degraded soils. The obtained research results confirmed the improvement of the soil sorption capacity (cation exchange capacity) caused by the addition of spent ion exchange sorbents. They also enabled to determine the magnitude of changes of the analyzed parameters depending on the amount of wastes introduced to the soil. The addition of 1% (w/w) spent cation exchanger enables to increase the cation exchange capacity twice, whereas in the case of zeolite, the observed increase reaches about 20%. Simultaneously, introduction of waste ion exchange sorbents increases the content of exchangeable calcium and magnesium while doubling in the content of these macroelements is observed for 5% (w/w) and 2% (w/w) of spent ion exchanger, respectively. In the case of the exchangeable potassium content, a satisfactory increase is observed with 1% (w/w) addition of spent zeolite.
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