Search

Anaerobic digestion is an optimal way to utilize organic materials or energy crops for bioenergy production. The current study set out to evaluate the impact of different rates of nitrogen present in mineral and organic (digestate) fertilizers on the changes in soil nitrogen. The soil of the experimental site is an Endohypogleyic Calcaric Luvisol in which cocksfoot (Dactylis glomerata) cultivar 'Amba' was grown. The experimental findings of 3 consecutive years (2013-2015) suggested that soil total nitrogen (Nt) content (0-30 cm layer) was higher in the treatments that had received biogas digestate fertilization compared to the untreated control. The significantly highest Nt concentration was established in the treatments applied with the highest biogas digestate nitrogen rate (N450). Fertilization with mineral nitrogen (Nmin) and digestate nitrogen resulted in a relatively higher Nmin accumulation in the upper soil layer (30 cm) compared to the deeper layer (30-60 cm). With the changes in mineral nitrogen, the most intensive soil Nt transformation processes occurred in the upper soil layer. Significantly higher Nmin concentrations were determined in the plots applied with mineral nitrogen compared to the other experimental treatments. The highest values of soil Nmin were determined in July: 47.7 in the 0-30 cm and 17.4 mg kg-1 in the 30-60 cm layer. [ABSTRACT FROM AUTHOR]

The present study was aimed at setting up and testing an experimental procedure to evaluate the anaerobic degradability of grasses and legumes by short term batch tests. The experiment was performed with the manometric OxiTop Control system. Biogas release of the 3 plant species (cocksfoot, lucerne and and fodder galega) of the 3rd cut was influenced by their chemical composition. The greatest differences between species were obtained in nitrogen, water soluble carbohydrates, hemicellulose and cellulose. Cocksfoot biomass had the lowest ADL concentration and the highest hemicellulose content, which was 3.5 times higher than that of lucerne and 11.0 times higher than that of fodder galega. According to the chemical composition, cocksfoot seems to be the most appropriate feedstock for biogas production, because it contains the lowest concentration of ADL, ADF and ash, the highest concentration of NDF and hemicellulose, WSC and the most appropriate C:N. The curve of biogas production from legumes, which contain more nitrogen and proteins, less hemicellulose was sharper, but biogas pressure was more than twice lower compared to that of cocksfoot. It was concluded that perennial grass cocksfoot of the late (3rd) cut was proved to be much more suitable for the biogas production compared to the legumes lucerne and fodder galega. [ABSTRACT FROM AUTHOR]

Re-naturalisation was investigated in 2012 on a peat bog (Pachiterric Histosol) with a non-removed peat layer at the former Radviliskis Experimental Station of the Lithuanian Institute of Agriculture in the site of the long-term field experiment, which had been completed 12 years ago. Peat samples were taken from 0-10, 10-20 and 20-30 cm layers in 3 field replicates. Chemical analyses were carried out at the Chemical Research Laboratory of Institute of Agriculture, LRCAF. The previously differently used peat soil contained different stocks of organic carbon (SOC). SOC stocks in the soil occupied with grassland were greater than those in peat soil previously not used for agriculture. The largest stock of MHA was in fonner unfertilised perennial grasses (0-30 cm)- 78.67% compared with other treatments. MHA content increased with increasing depth. The lower stability of carbon compounds in 0-30 cm layer was determined in the peat previously un-used for agricultural purposes, which had the highest relative share (40.9%) of dissolved organic carbon (DOC), characterized by the highest lability. We concluded that the most efficient way to conserve and sustain organic carbon in peat is to grow perennial grasses under non-intensive management system. [ABSTRACT FROM AUTHOR]

Re-naturalisation was investigated in 2012 on a peat bog (Pachiterric Histosol) with a non-removed peat layer at the former Radviliskis Experimental Station of the Lithuanian Institute of Agriculture in the site of the long-term field experiment, which had been completed 12 years ago. Peat samples were taken from 0-10, 10-20 and 20-30 cm layers in 3 field replicates. Chemical analyses were carried out at the Chemical Research Laboratory of Institute of Agriculture, LRCAF. The previously differently used peat soil contained different stocks of organic carbon (SOC). SOC stocks in the soil occupied with grassland were greater than those in peat soil previously not used for agriculture. The largest stock of MHA was in former unfertilised perennial grasses (0-30 cm)- 78.67% compared with other treatments. MHA content increased with increasing depth. The lower stability of carbon compounds in 0-30 cm layer was determined in the peat previously un-used for agricultural purposes, which had the highest relative share (40.9%) of dissolved organic carbon (DOC), characterized by the highest lability. We concluded that the most efficient way to conserve and sustain organic carbon in peat is to grow perennial grasses under non-intensive management system. [ABSTRACT FROM AUTHOR]

The experiments were designed to estimate the effects of short-lived legume swards. Therefore, the mass of Trifolium pratense L., a mixture of Trifolium repens L. and Lolium multiflorum Lamk. and straw of Triticum aestivum L. were incorporated into the soil, and the effects of changes of soil humic substances and their quality in 0-25 cm soil layer were monitored in a clay loam Cambisol, in two years. In the first year, it was found that incorporation of T. repens and L. multiflorum mass increased the content of mobile humic acids, total humic acids and extractable humic substances (sum of humic and fulvic acids), compared with the respective values before the trial establishment. T. pratense mass increased only the content of mobile humic acids. Conditionally stable humic acid fractions were formed more intensively in the second year of legume mass and straw effect. The best quality of humus was observed using the mass of T. pratense, in combination with cereal straw. Based on our findings, we conclude that the mass of legume swards used as green manure influenced the increase of humic substances only for one year after incorporation. Increases of stable humic substances were determined using the mass of legume swards, in combination with cereal straw. [ABSTRACT FROM AUTHOR]