Heavy metals accumulation in crops and soils poses a significant threat to the human health. A study was carried out in 2016 in order to assess hemp (Cannabis sativa L.) ability to accumulate heavy ...metals and to reveal its possibility as a phytoaccumulator or phytostabilizer. Two soil types from Croatia were used in experimental pots: Gleysoils (alkaline soil) and Stagnic Luvisol (acid soil). Majority of the varieties accumulated more heavy metals in roots than in above-ground biomass. Removal of Cd, Ni, Pb, Hg, Co, Mo and As was higher in acid soil. Potential ability for phytostabilization was observed in alkaline soil in order Cu > Cr > Cd > Mo > Hg > Zn > Ni > Co > As > Pb, while for acid soil in order Zn > Cd > Cr > Ni > Hg > Cu > Mo > As > Co > Pb. Some varieties exhibited a translocation coefficient (TC) more than 1 and shown the ability of hyper-accumulation for Zn, Hg, Mo and Cd. Higher accumulation of heavy metals in some varieties could lead to their general application for phytoaccumulation of heavy metals from polluted soils.
Accumulated copper (Cu) in agricultural soils is non-biodegradable and persists in the environment, which imposes the need for its regular monitoring by selective, rapid, simple, and low-cost ...analytical techniques. The performance of portable X-ray fluorescence spectrometers (pXRF) has significantly improved in the last ten years, and they are increasingly applied for environmental, agronomic, and soil science purposes. This study aims to compare the total Cu content determined in agricultural soil samples using three analytical methods (inductively coupled plasma mass spectrometry, (ICP-MS), atomic absorption spectrophotometry (AAS), and pXRF). The research was based on analyses of thirty-five soil samples collected from two vineyards, arable land, and a meadow located in North-West Croatia. In air-dried, milled, and homogenized soil samples, Cu content was detected using a hand-held XRF analyzer under laboratory conditions, while ICP-MS and AAS analysis were performed after open digestion by aqua-regia. Determined Cu content varied in very similar ranges from 51.2 mg/kg to 444.3 mg/kg with an average of 138.9 mg/kg for AAS; from 48.6 mg/kg to 446.4 mg/kg and an average of 139.7 mg/kg for ICP-MS and from 54.0 mg/kg to 435.3 mg/kg with an average of 141.3 mg/kg for pXRF. A high positive correlation between Cu content determined by pXRF and ICP-MS (R2 = 0.996), as well as between pXRF and AAS (R2 = 0.997), along with the results of Bland-Altman statistical analysis indicate that pXRF can be applied as a reliable tool for analyses of Cu-contaminated agricultural soil.
Pipeline spills and pollution of the environment by crude oil pose a threat to natural resources, especially soil and water. One such incident occurred on 25 September 2018 in the area of Budrovac ...(Croatia; 46°00′14.6″ N 17°04′16.8″ E) on agricultural land as a pipeline spill. Bioremediation of the contaminated soil was carried out with organic pollutants using an environmentally safe absorbent Spill-Sorb (Canadian Sphagnum Peat Moss) and a mineral fertilizer—nitrogen. The experiment was conducted in the greenhouse of the Faculty of Agriculture, Croatia, during a six-month (October 2018–April 2019) study. Samples of agricultural soils contaminated with total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) were taken after the rupture of the local gas condensate pipeline. The experiment was conducted in five treatments in triplicate: I-control (clean soil); II-100% contaminated soil + organic absorbent + nitrogen; III-100% contaminated soil + organic absorbent; IV-50% clean soil + 50% contaminated soil + organic absorbent + nitrogen; and V-50% clean soil + 50% contaminated soil + organic absorbent. The soil properties studied were pH, organic matter content, carbon and nitrogen content and ratio, and changes in the concentration of potential organic contaminants—TPHs and individual PAHs. The results demonstrated that the mixture of organic absorbent and nitrogen efficiently removed organic pollutants from the contaminated soil within six months. However, the application of Spill-Sorb alone was more effective for the degradation of hydrocarbons. The effectiveness of the absorbent studied was dependent on the concentration of organic pollutants and nitrogen application.
According to the Scopus database, over the last five years, 91 scientific papers with the keyword “pXRF” (portable X-ray fluorescence) were published in indexed journals in the domain of ...environmental science and agricultural science, which indicates more frequent applications of this technique in scientific research. The pXRF method is characterized by speed, precision, accuracy, and the possibility of a simultaneous analysis of a large number of elements, albeit with higher limits of detection (LODs) as a major disadvantage. The presence of metals in certain phosphate fertilizers is well established, though not to the same extent as in mineral nitrogen fertilizers. The aim of this research was to determine the metal content (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Si, Sr, Th, U, Zn, Zr, and Y) in thirteen commercial mineral nitrogen fertilizers via the pXRF method. Six straight fertilizers (ammonium nitrate, ammonium sulphate nitrate, limestone ammonium, nitrate, and urea) and seven complex fertilizers (various NPK formulations), which are different even according to their production technology, produced in Croatia were analyzed using the handheld Vanta C (Olympus) XRF analyzer according to the loose powder method and “point and shoot” technique. Data quality control was performed by analyzing the reference fertilizer samples and certified and reference soil samples. The results revealed that the determined contents of Cd, Mn, and Th were relatively higher in the single-component fertilizers, while the contents of As, Cr, Fe, Ni, Si, Sr, Zn, Zr, Y, and U were relatively higher in the complex fertilizers. Due to the higher LODs of Co and Pb (3 mg/kg) and Mo (2 mg/kg), the pXRF method was not appropriate for the determination of these metals in the analyzed fertilizers. The quantified metal content in the analyzed fertilizers varied as follows: 2.0–8.0 mg As/kg; 11.5–31.3 mg Cd/kg; 29.8–118.5 mg Cr/kg; 7.8–26.3 mg Cu/kg; 16.5–2209 mg Fe/kg; 20.3–5290 mg Mn/kg; 6.2–27.8 mg Ni/kg; 1156–4581 mg Si/kg; 2.0–469.8 mg Sr/kg; 3.0–35.3 mg Th/kg; 2.0–82.8 mg U/kg; 1.4–166 mg Zn/kg; 9.7–15.3 mg Zr/kg; and 16.5–128.0 mg Y/kg. The results indicated that the pXRF method is particularly suitable for measurement and metal detection in complex nitrogen mineral fertilizers with higher amounts of metals, but it is not suitable for the detection and quantification of the lower amounts of As, Zr, Y, Cu, Ni, and Cr in single-component nitrogen fertilizers. Compared to all of the investigated fertilizers, the highest amounts of As, Cr, Cu, Fe, Ni, U, Zn, and Zr were quantified in the NPK 7-20-30 formulation.
Little is known about the bonfire impact on microbial properties in soil. This work aimed to study moderate- to high-severity experimental burning (250 °C) compared to unburned Cambisol in a natural ...Mediterranean environment (Croatia) on selected soil properties. The soil was sampled immediately and 1, 2, 4, and 6 months after the fire. The fire increased the mean weight diameter, water stable aggregates, and water repellence in different soil fractions, and the observed effect was the strongest immediately after the fire. It also altered soil pH, electrical conductivity, total nitrogen carbon, and sulphur content, and completely destroyed carbapenem-resistant bacteria, but did not significantly affect the soil’s mineralogical properties. Six months after the fire, most microbial properties (save for pH) returned to near control values. Heterotrophic, sporogenic, and phosphate-solubilising bacteria started to recover after a month, whereas the population of carbapenem-resistant bacteria was destroyed initially, but recovered by the fourth month after the fire. Dehydrogenase activity was not significantly affected, but proper recovery started four months after the fire. Even though Cambisol showed some resilience to fire and its properties mostly returned to normal by the sixth month, and a full recovery is expected to occur later, as vegetation returns.
Soil and water loss due to traditional intensive types of agricultural management is widespread and unsustainable in Croatian croplands. In order to mitigate the accelerated land degradation, we ...studied different cropland soil management strategies to obtain feasible and sustainable agro-technical practices. A rainfall simulation experiment was conducted at 58 mm h–1 over 30 min on 10 paired plots (0.785 m2), bare and straw covered (2 t ha−1). The experiment was carried out in maize cultivation (Blagorodovac, Croatia) established on Stagnosols on slopes. Measurements were conducted during April (bare soil, after seeding), May (five-leaves stage), and June (intensive vegetative growth) making 60 rainfall simulations in total. Straw reduced soil and water losses significantly. The highest water, sediment loss, and sediment concentrations were identified in tillage plots during May. Straw addition resulted in delayed ponding (for 7%, 63%, and 50% during April, May and June, respectively) and runoff generation (for 37%, 32%, and 18% during April, May and June, respectively). Compared with the straw-mulched plot, tillage and bare soil increased water loss by 349%. Maize development reduced the difference between bare and straw-mulched plots. During May and June, bare plots increase water loss by 92% and 95%, respectively. The straw mulch reduced raindrop kinetic energy and sediment detachment from 9, 6, and 5 magnitude orders in April, May, and June, respectively. Overall, the straw mulch was revealed to be a highly efficient nature-based solution for soil conservation and maize cultivation protection.
Conservation tillage harmonizes soil protection with demands of the crop, soil and climate. The continuous conservation tillage improves soil properties and modifies impact of weather extremes. The ...aim of the paper was to investigate the changes in four soil physical states affected by soil conservation tillage and to evaluate soil water content in a critical period. The study was carried out on Chernozems applying six tillage treatments, that are loosening, ploughing, tine tillage (a deeper, and a shallower), disk tillage and direct drilling. The investigation suggested that soil conservation was the major solution resulting in the balanced water content (SWC) and penetration resistance values in both treatments under peculiar weather conditions. However, the crumb ratio and the crusted area resulted in significant differences between the treatments, presumably due to the level of surface preservation. Soil water content differed significantly between months, with higher contents in spring and lower values in the end of summer. The higher SWC expected at the beginning of the growing season was reliably fulfilled, but the SWC level for workabilty differed from the optimum.
The stationary field experiment on the application of different types and doses of liming was started in Kupres plateu (1.184 m.a.s.l.), Bosnia and Herzegovina in the summer 2017. The aim of this ...three-year research was to determine the effectiveness of liming materials on changes in soil chemical properties and yield of cultivated crops. The used treatments were; control, crude dolomite from Rama, crude dolomite from Kupres, and commercial burnt lime; each applied at lower and higher dosages of 7 and 15 t/ha, respectively. Application of lime materials resulted in desirable reduction in soil acidity, and changes in the soil chemical complex with an increase of exchangeable Ca2+ after limestone application and increase of exchangeable Mg2+ after dolomite application. Commercial burnt lime (BLP) proved to be most effective, followed by crude dolomite Rama (CDR), while crude dolomite Kupres (CDK) proved to be the least effective. All cultivated crops (silage corn > triticale > spring barley) responded positively to the applied lime materials. In terms of investment and yields achieved, silage corn proved to be the most economical.
Agricultural ecosystems can play a significant role in greenhouse gas emissions, specifically, carbon dioxide. Tillage management can increase atmospheric CO2concentrations and contribute to global ...warming but it is uncertain to which extent tillage enhances the transfer of soil CO2 to the atmosphere. Our objectives were (1) to determine short-term, tillage-induced soil CO2 emissions; (2) to determine the effect of different tillage systems and time after tillage operation on soil CO2emissions and soil microclimate and (3) to examine the relations between short-term soil CO2 emissions and microclimate (soil temperature, soil water content; air temperature and relative air humidity). Soil CO2 concentrations were measured on Stagnic Luvisols, in a temperate continental climate of the central lowland Croatia in October 2013 before, zero and three hours after tillage operations with in situ closed static chamber method. The four tillage systems were no-tillage (NT), ploughing to 25 cm (P25), very deep ploughing to 50 cm (P50) and subsoiling to 50 cm (PS50). The study showed that tillage has impact on soil CO2 emissions and soil microclimate. Tillage has accelerated the transfer of soil CO2 to the atmosphere but soil CO2 emissions declined sharply within three hours after tillage operations. Soil temperature has decreased after tillage operation and afterwards continued to rise while soil water content has been decreasing during whole study period. Correlations between soil CO2 emissions and microclimatic factors were mostly weak or modest while best type of studied correlations between soil CO2emissions and microclimate showed to be the second order polynomial correlation.
The sustainability of agroecosystems is closely related to successful soil conservation. Sustainable land use practices are crucial to reduce the impacts of agriculture on land degradation and ...maintain long-term soil productivity. In this context, is important to avoid practices that deteriorate the soil (e.g. soil erosion), and find the most suitable to maintain soil and crops productivity. The objective of this work is to compare the impact of different tillage systems on soil compaction, erosion and crop production on clay loam Stagnosols in Croatia. Three tillage treatments were studied: conventional tillage (CT), no-tillage (NT) and deep tillage (DT). Soil water content, bulk density and penetration resistance were determined in the 0–10, 10–20, 20–30 and 30–40cm soil depths. Soil erosion was measured during rainfall events. The results showed that tillage treatments influenced the soil physical parameters, soil loss and crop yields. During first four years of study NT increased (p<0.05) bulk density in the 0–10cm depth by an average of 8% and 7% in relation to CT and DT. Conventional tillage treatment increased (p<0.05) bulk density in the 30–40cm depth by an average of 6% and 5% in relation to NT and DT. No-tillage treatment had a significantly higher penetration resistance (PR) comparing to CT and DT in 2012 and 2014. During the flowering time of 2013, PR was significantly higher in NT at 20–30cm depth than in the other treatments. This was observed also in 2014 at 20–30 and 30–40cm depth. Average annual soil loss under NT (0.53tha−1year−1) and DT (3.11tha−1year−1) were significantly lower than that under CT (13.11tha−1year−1). No-tillage had lower crop grain yields compared to CT and DT, but higher yields in dry years, as consequence of the high capacity for water retention. We recommended DT treatment for investigation at the field scale to assess its suitability for wider application on clay loam soils on sloped areas.
•No-tillage (NT), conventional tillage (CT) and deep tillage (DT) were investigated.•Topsoil compaction had the followed order NT>CT>DT. Subsoil compaction increased in CT.•Soil erosion rates were lower in NT and DT than in CT.•Crop yields were higher in NT than CT in dry years.
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