Josef Kozák

Impact of varying soil structure on transport processes in different diagnostic horizons of three soil types

When soil structure varies in different soil types and the horizons of these soil types, it has a significant impact on water flow and contaminant transport in soils. This paper focuses on the effect of soil structure variations on the transport of pesticides in the soil above the water table. Transport of a pesticide (chlorotoluron) initially applied on soil columns taken from various horizons of three different soil types (Haplic Luvisol, Greyic Phaeozem and Haplic Cambisol) was studied using two scenarios of ponding infiltration. The highest infiltration rate and pesticide mobility were observed for the Bt(1) horizon of Haplic Luvisol that exhibited a well-developed prismatic structure. The lowest infiltration rate was measured for the Bw horizon of Haplic Cambisol, which had a poorly developed soil structure and a low fraction of large capillary pores and gravitational pores. Water infiltration rates were reduced during the experiments by a soil structure breakdown, swelling of clay and/or air entrapped in soil samples. The largest soil structure breakdown and infiltration decrease was observed for the Ap horizon of Haplic Luvisol due to the low aggregate stability of the initially well-aggregated soil. Single-porosity and dual-permeability (with matrix and macropore domains) flow models in HYDRUS-1D were used to estimate soil hydraulic parameters via numerical inversion using data from the first infiltration experiment. A fraction of the macropore domain in the dual-permeability model was estimated using the micro-morphological images. Final soil hydraulic parameters determined using the single-porosity and dual-permeability models were subsequently used to optimize solute transport parameters. To improve numerical inversion results, the two-site sorption model was also applied. Although structural changes observed during the experiment affected water flow and solute transport, the dual-permeability model together with the two-site sorption model proved to be able to approximate experimental data.

Pesticide adsorption in relation to soil properties and soil type distribution in regional scale.

Study was focused on the evaluation of pesticide adsorption in soils, as one of the parameters, which are necessary to know when assessing possible groundwater contamination caused by pesticides commonly used in agriculture. Batch sorption tests were performed for 11 selected pesticides and 13 representative soils. The Freundlich equations were used to describe adsorption isotherms. Multiple-linear regressions were used to predict the Freundlich adsorption coefficients from measured soil properties. Resulting functions and a soil map of the Czech Republic were used to generate maps of the coefficient distribution. The multiple linear regressions showed that the K(F) coefficient depended on: (a) combination of OM (organic matter content), pH(KCl) and CEC (cation exchange capacity), or OM, SCS (sorption complex saturation) and salinity (terbuthylazine), (b) combination of OM and pH(KCl), or OM, SCS and salinity (prometryne), (c) combination of OM and pH(KCl), or OM and ρ(z) (metribuzin), (d) combination of OM, CEC and clay content, or clay content, CEC and salinity (hexazinone), (e) combination of OM and pH(KCl), or OM and SCS (metolachlor), (f) OM or combination of OM and CaCO(3) (chlorotoluron), (g) OM (azoxystrobin), (h) combination of OM and pH(KCl) (trifluralin), (i) combination of OM and clay content (fipronil), (j) combination of OM and pH(KCl), or OM, pH(KCl) and CaCO(3) (thiacloprid), (k) combination of OM, pH(KCl) and CEC, or sand content, pH(KCl) and salinity (chlormequat chloride).

Comparing Different Data Preprocessing Methods for Monitoring Soil Heavy Metals Based on Soil Spectral Features

Gholizadeh A., Borůvka L., Saberioon M.M., Kozak J., Vasat R., Němecek K. (2015): Comparing different data pre processing methods for monitoring soil heavy metals based on soil spectral features. Soil & Water Res., 10: 218–227. The lands near mining industries in the Czech Republic are subjected to soil pollution with heavy metals. Ex cessive heavy metal concentrations in soils not only dramatically impact the soil quality, but also due to their persistent nature and indefinite biological half-lives, potentially toxic metals can accumulate in the food chain and can eventually endanger human health. Monitoring and spatial information of these elements require a large number of samples and cumbersome and time-consuming laboratory measurements. A faster method has been developed based on a multivariate calibration procedure using support vector machine regression (SVMR) with cross-validation, to establish a relationship between reflectance spectra in the visible-near infrared (Vis-NIR) region and concentration of Mn, Cu, Cd, Zn, and Pb in soil . Spectral preprocessing methods, first and second derivatives (FD and SD), standard normal variate (SNV), multiplicative scatter correction (MSC), and continuum removal (CR) were employed after smoothing with Savitzky-Golay to improve the robustness and performance of the calibration models. According to the criteria of maximal coefficient of determination ( R 2 cv ) and minimal root mean square error of prediction in cross-validation ( RMSEP cv ), the SVMR algorithm with FD preprocessing was determined as the best method for predicting Cu, Mn, Pb, and Zn concentration, whereas the SVMR model with CR preprocessing was chosen as the final method for predicting Cd. Overall, this study indicated that the Vis-NIR reflectance spectroscopy technique combined with a continuously enriched soil spectral library as well as a suitable preprocessing method could be a nondestructive alternative for monitoring of the soil environment. The future possibilities of multivariate calibration and preprocessing with real-time remote sensing data have to be explored.

Geostatistical investigation of a reclaimed dumpsite soil with emphasis on aluminum

Abstract Spatial heterogeneity of dumpsite soils differs from that of natural soils due to their anthropogenic origin, which makes description of their properties more complicated. In anthropogenic soil of a reclaimed dumpsite in Northern Bohemia, the spatial distribution and interrelations among basic soil properties and two aluminum forms were studied by a combination of factor analysis and geostatistics. Similar distribution patterns were found for soil pH, exchangeable acidity, oxidizable carbon content, pyrophosphate-extractable organic carbon and labile Al. Humus quality parameter ( A 400 / A 600 ratio) and Al extractable with sodium pyrophosphate showed different spatial distributions. Ranges of variogram models (spherical with nugget) for most of these variables were between 280 and 290xa0m; their distribution patterns were related to topsoil reclamation management. In factor analysis, three factors explaining 83.8% of total variation were selected and their interpretation was facilitated by kriging. The first factor accounted for positive effects of soil reclamation, including decreasing soil acidity and labile aluminum content, whereas the influence of afforestation, especially on humus quality and content, was well pronounced in the second factor. The effect of depositing, indicated by elevation, was probably expressed in the third factor influencing aluminum content extractable with sodium pyrophosphate. Geostatistics proved to be useful for anthropogenic soils on reclaimed areas where spatial distribution of soil properties is determined more by human activity than by natural evolution.

Soil legacy data rescue via GlobalSoilMap and other international and national initiatives

Legacy soil data have been produced over 70 years in nearly all countries of the world. Unfortunately, data, information and knowledge are still currently fragmented and at risk of getting lost if they remain in a paper format. To process this legacy data into consistent, spatially explicit and continuous global soil information, data are being rescued and compiled into databases. Thousands of soil survey reports and maps have been scanned and made available online. The soil profile data reported by these data sources have been captured and compiled into databases. The total number of soil profiles rescued in the selected countries is about 800,000. Currently, data for 117, 000 profiles are compiled and harmonized according to GlobalSoilMap specifications in a world level database (WoSIS). The results presented at the country level are likely to be an underestimate. The majority of soil data is still not rescued and this effort should be pursued. The data have been used to produce soil property maps. We discuss the pro and cons of top-down and bottom-up approaches to produce such maps and we stress their complementarity. We give examples of success stories. The first global soil property maps using rescued data were produced by a top-down approach and were released at a limited resolution of 1km in 2014, followed by an update at a resolution of 250m in 2017. By the end of 2020, we aim to deliver the first worldwide product that fully meets the GlobalSoilMap specifications.

Land use analysis in terms of farmland protection in the Czech Republic.

Janků J., Sekáč P., Baráková J., Kozák J. (2016): Land use analysis in terms of farmland protection in the Czech Republic. Soil & Water Res., 11: 20–28. The agricultural land acreage in Central Europe, including the Czech Republic, rapidly decreases. This study presents the trends of agricultural land acreage reduction in the period 1966–2013, with respect to the 1990 milestone (political changes triggering a rapid loss of agricultural land for construction purposes). The analysis is based on the cadastral register data. Particularly serious is the rapid reduction of arable land – 25 ha per day. Furthermore, the actual built up area seems to be larger than show the records on the construction land in the cadastral register. There is an obvious discrepancy between the real state and the cadastral data, so the actual reduction of arable land in the Czech Republic may be even greater. Unfortunately, some municipalities responsible for the urban planning process are obviously not interested in land protection. Based on their quality, the Czech land protection law classifies the soils into 5 protection classes. The areas with the first and second class soils should not be used for construction purposes. However, the study revealed the law is frequently neglected from the part of municipalities and the areas of best quality soils have often been sealed by construction. The present study also attempted to enumerate the financial losses from crop production associated with the land take. The ineffective land protection is a very serious Europe-wide problem.

Estimation of land loss in the Czech Republic in the near future

Janků J., Jakšík O., Kozák J., Marhoul A.M. (2016): Estimation of land loss in the Czech Republic in the near future. Soil & Water Res., 11: 155−162. The study presents an estimate of how many hectares of soil will be removed from the farmland fund in the coming years around the biggest towns for non-agricultural use, such as for residential purposes and industrial zones. To estimate suburban area spreading, so called “buffers”, i.e. packing zones around towns, were established. For the capital city of Prague the buffer width was set at 3 km, for regional towns at 2 km, and for district towns at 1 km. In this area, as well as on the territory (intravilan) of towns, the estimate of the future acreage removal of farmland for building purposes was calculated. The study also quantifies the changes in acreage of different soil types. The results show a significant decrease in acreage of the best quality soils, primarily because the largest towns are usually built on the best soils, and these towns are spreading much more than small towns. The results were statistically processed for (a) total, (b) each regional town, (c) each district town, and (d) total always separately for urban areas, for suburban areas (buffer zones), and for their combinations. Cambisols represent the soil group with the largest loss of land, followed by Luvisols and Chernosols.

Field Study and Modeled Transport of Chlortoluron in Different Soil Types of the Czech Republic

Chlortoluron transport was studied in five different soil types in five locations in the Czech Republic. There were considerable differences in herbicide transport with varying soil types and locations. The BPS mathematical model (Kozak and Vacek, 1996) was used to simulate chlortoluron transport. The chlortoluron concentrations that were predicted by the model were similar to the measured data except in the Greyic Phaozem, where preferential flow may have greatly influenced solution transport.