Jacek Długosz

The impact of a bio-fertilizer on the soil organic matter status and carbon sequestration—results from a field-scale study

PurposeThe application of bio-fertilizers is one of the management practices that can help to maintain or increase the content of organic matter (OM) and improve soil fertility in arable soils. While some results have been obtained in relation to the influence of bio-fertilizers on organic matter content, less in known about the fractional composition of humus.Materials and methodsThe aim of this study was to determine the effects of the bio-fertilizer UGmax on soil total organic carbon (TOC), dissolved organic carbon (DOC), and the fractional composition of organic matter (C of humic acids (CHAs), C of fulvic acids (CFAs), and C in humins) in the humus horizon of an arable field. Measurements were taken in 2005 before the application of UGmax and in 2008, 3xa0years after its application, which was done in 2005, 2006, and 2007. Forty soil samples were taken in 2005 (the control year without UGmax), while 20 samples were taken after UGmax treatment and 20 from the control in 2008. Samples were always collected after the plants were harvested.Results and discussionAfter the 3-year period of the experiment, the TOC content was 6.3xa0% higher in plots on which UGmax was applied in comparison to the control, while the DOC content was 0.19 percentage points lower after 3xa0years of bio-fertilizer use as compared to the initial year of the experiment. The contribution of DOC to TOC decreased significantly after the application of UGmax in comparison with the control. The content of CFAs and its contribution in the TOC pools in soil without UGmax was higher at the end of the experiment compared to the beginning, while there was an inverse relationship in the soil with the bio-fertilizer. In comparison with the control, organic matter in the soil treated with UGmax had a higher content of C of humic acids, C in humins, and higher CHAs/CFAs ratio.ConclusionsWe conclude that the use of a bio-fertilizer that increases the stable fractions of organic matter provides evidence of an increase in the soil OM stability. In turn, the contribution of the organic matter fractions that are more resistant to decomposition is crucial for increasing soil carbon sequestration.

Spatio-temporal variations of soil properties in a plot scale: a case study of soil phosphorus forms and related enzymes

PurposeSpatio-temporal variability in soil properties has long been observed on uniformly managed fields. Understanding the spatial characteristics of soil properties would be helpful in recognizing their relationship and the development of site-specific management techniques. The objective of this study was to determine the spatio-temporal variation of P forms and related enzymes and their relationship with some physico-chemical properties in a plot scale.Materials and methodsA grid soil sampling (10u2009×u200910xa0m) was used to measure the spatial variation of soil properties across a 0.4-ha field. Soil samples were collected at 50 points from the upper 20xa0cm of luvisols in April and August 2007. The total (PT), available (PA), inorganic (PI), organic (PO) phosphorus concentration, and acid (PAC) and alkaline (PAL) phosphatase activity were analyzed. Additionally, total organic carbon (TOC), soil pHKCl, and clay content were determined. Data were evaluated using classical statistical and geostatistical methods.Results and discussionBoth enzyme activities were significantly higher in April than in August, while the PT and PI concentration were significantly lower. The concentrations of PO and PA did not significantly differ between sampling dates. The spherical or mixed (spherical/linear) models with the nugget effect were fitted to the calculated semivariograms. The PA and TOC concentrations on both sampling dates as well as PAC activity in April were situated in the strong variability class, the PI concentration in April revealed a weak spatial variability and the other properties were in the moderate variability class. The clay content revealed a pure nugget effect. The range of the influence that was calculated for the properties ranged from 16.5 to 50.0xa0m. Kriged maps showed that temporal variability was observed in the spatial patterns of the PI and TOC concentrations and PAC activity.ConclusionsResults from this study can help us to understand and predict the contribution of internal factors (i.e., soil type) in the total variability of soil properties that can interfere with the influence of soil management practices. The spatio-temporal variability showed that the studied area was temporally unstable and the implication of these findings is that more frequent sampling, at least several times throughout the growing season, must be included in the sampling strategy in order to better understand whether P forms and related enzymes show any permanent spatial patterns in soil all of the time or whether they are more randomized.

Heavy Metals Bioaccumulation in Tissues of Spiny-Cheek Crayfish (Orconectes limosus) from Lake Gopło: Effect of Age and Sex

The aim of the present work was to assess the concentrations of metals in the abdominal muscle and exoskeleton of 3-year-old males and 4-year-old females and males of spiny-cheek crayfish (Orconectes limosus) collected from Lake Gopło. A total of 93 males and 35 females were collected in autumn (October 2014). The analyzes of heavy metals were conducted by means of atomic absorption spectroscopy with a PU9100X spectrometer. The content of mercury was determined using AMA 254 mercury analyser. As analyses indicated heavy metals accumulated in the muscle and exoskeleton in the following sequence: Znu2009>u2009Cuu2009>u2009Pbu2009>u2009Mnu2009>u2009Niu2009>u2009Hg and Mnu2009>u2009Pbu2009>u2009Znu2009>u2009Niu2009>u2009Cuu2009>u2009Hg, respectively. Statistically significant differences between 3- and 4-year-old males were found for all analyzed metals. Gender dependent differences were calculated only for Ni in the muscle tissue and for Mn and Hg in the exoskeleton. In comparison with the study carried out 2 years ago notably higher concentrations of Pb were found in the muscle and a higher content of Zn, Pb, Mn and Ni was determined in the exoskeleton.

Spatio-temporal heterogeneity of soil microbial properties in a conventionally managed arable field

PurposeKnowledge about the spatio-temporal variability of soil microbial properties is crucial in evaluating their structure-function relationship and their impact on ecosystem functions. The aim of the study was to determine the spatio-temporal variation of the selected microbial properties at the surface horizon in a conventionally managed arable field.Materials and methodsThe area selected for the research, which was mainly covered with typical Luvisols, was a uniformly managed system that was considered to be homogenous in respect to texture (mostly loamy fine sand). Winter wheat was cultivated after winter rape as the forecrop. A grid soil sampling (10xa0mu2009×u200910xa0m) was used to assess the spatial heterogeneity of soil properties across a 0.5-ha field. Soil samples were collected at 50 points from the upper 20xa0cm of soil in April and August 2007. Colony-forming units (CFUs) of bacteria, fungi and actinomycetes, and basal respiration (BR) were analyzed. Data were evaluated using classical statistical and geostatistical methods.Results and discussionFungal CFUs were significantly lower than the bacterial ones with a B/F (bacteria/fungi) ratio of 80.0 in April and 45.1 in August. Bacterial CFUs, B/F ratio, and BR level revealed significantly higher values in April than in August, while fungi showed the opposite trend. Other studied properties did not show significant differences between sampling months. Only some of the properties, such as the bacterial community in August, the number of actinomycetes in April, and qCO2 on both sampling dates, revealed significant spatial autocorrelation (Moran’s I) and were spatially dependent at the scale of sampling grid, whereas the qCO2 revealed a higher differentiation in the spatial pattern between April and August than the other studied properties. Most of the spatially correlated properties were in the weak variability class (a nugget effect >u200975%), while only the qCO2 (August) ratio was in the moderate variability class (a nugget effect between 25 and 75%).ConclusionsMost of the microbial-related properties did not exhibit a spatial structure at the examined scale, thus suggesting that changes in these properties would be detectable at a distance shorter than 10xa0m. More frequent seasonal sampling must be included in the sampling strategy in order to better understand whether studied properties show any permanent spatial patterns in soil over time or whether they are more randomized.