Biochar usually has a large specific surface area, and due to this, it increases the sorption capacity of the soil where it was applied. The objectives of this study were to (i) quantify the effects of biochar and biochar in combination with N fertilizer on the soil sorption parameters and (ii) quantify the effects of soil organic matter on the sorption parameters after application of biochar with and without N fertilizer.
Materials and methods
The experiment was established on Haplic Luvisol at the locality of Dolná Malanta (Slovakia) in 2014. The soil samples were collected once a month from the depth 0–0.2 m during 2014 to 2016. The field experiment included three rates of biochar application (B0?=?no biochar, B10?=?biochar at the rate of 10 t ha?1, B20?=?biochar at the rate of 20 t ha?1) and three levels of N fertilization (N0?=?no nitrogen, N40?=?nitrogen at the rate of 40 kg ha?1, N80?=?nitrogen at the rate of 80 kg ha?1).
Results and discussion
Overall, the decrease of the average values of hydrolytic acidity due to biochar and biochar combined with N fertilization resulted on average in an increase of sum of basic cation (SBC), cation exchange capacity (CEC), and sorption capacity of soil organic matter (CECSOM) in all treatments. However, this effect was the most intensive in B10N40. Despite the fact that the average values of sorption parameters improved, its dynamics during the investigated period were different. A significant decrease in CEC was observed from 2014 to 2016 in all treatments, except B0N0 and B10N0. A stable trend in CECSOM was observed only in B10N40. Humic substances and humic acids had a statistically significant positive effect on the SBC, CEC, and CECSOM only in B20N0 treatment. Negative correlations between the above mentioned parameters were observed in B10N80 treatment.
Conclusions
We conclude that the application of biochar and biochar combined with N fertilization had a positive influence on sorption parameters. However, its effects on SBC, CEC, and CECSOM decreased over time after its application.
The impact of regular application of sewage sludge or farmyard manure on the organic contaminant loads in soil was assessed in a model rhizobox experiment. Two soils originating from a long-term field crop rotation and fertilizer experiment running since 1996 were used. The total polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorinated pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) contents were determined in the rhizosphere and bulk soil. The results showed low but still detectable contents of PCBs and OCPs in the soil, substances which were banned a few decades ago. Among the OCPs, dichlorodiphenyltrichloroethane (DDT) and its metabolites reaching up to 18.2 µg kg?1 of the soil even exceeded the preventive levels for these compounds in agricultural soils, i.e. 7.5 µg kg?1 of soil. For PBDEs, PFOA, and PFOS, their contents in the soil significantly increased with sewage sludge application. The enhancement of the potential biodegradability of the POPs in the rhizosphere was confirmed only for hexachlorocyclohexane (γ-HCH), where, the level of γ-HCH increased significantly in the rhizosphere soil compared to bulk soil. Thus, natural attenuation of POPs in the soil-plant system seems to be insufficient for most of the investigated compounds. 相似文献
Journal of Soils and Sediments - River channel sediments have been widely used to trace current and historical pollution in fluvial systems, although they are not the only media employed for that... 相似文献
Further findings of tip beetles (Malachius; Col., Malachiidae) burdensome in buildings
There came about to the troublesome occurence of theMalachius larvae in two new-built rustic buildings and in the adapted house in the czechoslovakia (Centrral Bohemia, threen districts), just after settling in or in the third year after the outset of adaption works at th most. The larvae occured especially in March and April (the maximum extent November till July inclusively). It was repeated in the second year after the settling in one case. The entomofauna typical for the mouldy materials was ascertained in two investigated localities. The larvae were also at polluted egg crates ascertained (one another locality).The larvae ofCantharis fusca of the akin family Cantharidae infested egg stores of one modern poultry-farm (October 1973). There is a thick ruderal vegatation around the buildings. 相似文献
The field persistence and efficacy of Bacillus thuringiensis formulations
The persistence of spores ofBacillus thuringiensis (commercial formulation Dipel and Bathurin) on oak leaves under different climatic condition in field trials was determined.
The killing activity of these preparations against wintermothOperophthera brumata and green oak tortrix Tortrix viridana was parallely tested. Within the first week after the application of bacterial preparations
the viable spore count on leaves was reduced of two up to three orders. The efficacy of bacterial preparations depends, however,
on the environmental temperature occurring within the first week after the application. The adequate temperature is the primary
deciding for the feeding activity of caterpillars and for the virulence of the preparations. For aerial application doses
of 0.5 to 1.0 kg of the preparation in 50 100 l of water per one ha were sufficient. In the contrary, Dipel WP in oil suspension
was unsufficient for aerial application because of mechanical blocking of the nozzles. The optimal time for the procedure
was the first week of May in our climatic conditions.
相似文献
The importance of copper/amine based preservatives is increasing. Leaching of copper from wood preserved with these solutions
is still higher than leaching from wood impregnated with copper chromium ones. In order to decrease leaching, different carboxylic
acids (octanoic, 2-ethylhexanoic, decanoic) were added to copper/amine/boron aqueous solutions. An experiment of leaching
of copper from Norway spruce was performed according to the modified standard procedure (EN 1250). Results confirmed that
carboxylic acids significantly improve copper fixation. The best fixation was determined in specimens impregnated with the
preservative solutions consisting of copper, ethanolamine, boric acid and octanoic acid. From such wood, only 1.6% of copper
was leached. 相似文献
Gastric acid suppressants frequently are used in cats with acid‐related gastric disorders. However, it is not known if these drugs effectively increase intragastric pH in cats.
Objectives
To examine the effects of PO administered ranitidine and omeprazole on intragastric pH in cats and to compare the efficacy of once‐daily versus twice‐daily dosage regimens for omeprazole.
Animals
Eight domestic shorthair cats.
Methods
Using a randomized 4‐way cross‐over design, cats were given enteric‐coated omeprazole granules (1.1–1.3 mg/kg q24h and q12h), ranitidine (1.5–2.3 mg/kg q12h), and placebo. Intragastric pH was monitored continuously for 96 hours using the Bravo™ system1, starting on day 4 of treatment, followed by a median washout period of 12 days. Mean percentage of time pH was ≥3 and ≥4 was compared among groups using repeated measures ANOVA.
Results
Mean ± SD percentage of time intragastric pH was ≥3 and ≥4 was 67.0 ± 24.0% and 54.6 ± 26.4% for twice‐daily omeprazole, 24.4 ± 22.8% and 16.8 ± 19.3% for once‐daily omeprazole, 16.5 ± 9.0% and 9.6 ± 5.9% for ranitidine, and 9.4 ± 8.0% and 7.0 ± 6.6% for placebo administration. Twice‐daily omeprazole treatment significantly increased intragastric pH, whereas pH after once‐daily omeprazole and ranitidine treatments did not differ from that of placebo‐treated cats.
Conclusion and Clinical Importance
Only twice‐daily PO administered omeprazole significantly suppressed gastric acidity in healthy cats, whereas once‐daily omeprazole and standard dosages of ranitidine were not effective acid suppressants in cats. 相似文献
The content of Pb, Cd, Mn, K, Ca, Mg and 206Pb/207Pb isotope ratios in spruce tree rings (Picea abies) and peat cores from the Brdy Hills area (10 km W of the Pb smelter) were compared with those in spruce tree rings in the vicinity of the Pb smelter. Maximum Pb content in tree rings (up to 60 mg kg?1 Pb) corresponds to a peak of metallurgical production in the mid 1970s and highest smelter emissions in the early 1970s. The Pb concentration curves obtained from peat deposit profiles closely correlate with the Pb concentrations in tree rings at both sampling sites. The small differences between the individual tree cores, with the identical general trend, may be attributed to the difference in distance from the smelter and the altitude of each sampling site. Similar behaviour to Pb can be observed for Cd and Ca. Lead isotope composition in tree rings (206Pb/207Pb ~1.143–1.174) is controlled mainly by the smelter emissions (206Pb/207Pb ~1.16–1.17), with the exception of the youngest segments from the more distant locality from the smelter, which yield isotopic signatures corresponding to car-emission Pb (206Pb/207Pb ~1.143–1.150). Higher content of Mn, Mg and Ca in tree rings corresponding to the 1970s and 1980s may be related to soil chemistry changes caused by acid deposition. In addition, an increase in K, Mg (and in some cases also Mn) in the youngest part of wood cores corresponds to the physiological processes in sapwood, and may be influenced by a decrease in Pb in organic soil horizons, which limited the cycling of basic inorganic nutrients. 相似文献
The denitrifying enzyme activity (DEA), denitrification potential (DP) and anaerobic respiration (RESP) together with chemical
characteristics were measured in three contrasting soils collected from experimental arable plots that had been subjected
to long-term (21–23 years) fertilizer treatments. The plots sampled were either unfertilized or had received either annual
inorganic NPK, manure and lime, or inorganic NPK and manure treatments. Addition of inorganic NPK, manure and lime led to
large increases in the DEA for two of the three soils, but in the absence of lime, inorganic NPK and manure caused only small
increases in DEA compared to unfertilized soils. Both DP and RESP were increased by the addition of inorganic NPK, manure
and lime, but were substantially decreased by fertilizer treatments without lime. In most cases there was a simple relationship
between soil pH and either DEA and DP, with those treatments that reduced soil pH also leading to reduced denitrification
and vice versa. The effects of artificially increasing the pH to a value close to the pH in unfertilized soils (6.3) by addition
of NaOH to the soils that had received inorganic NPK, and which had the lowest soil pH values, were to increase substantially
DEA, DP and RESP. In soil from one of the sites that had been stored for 5 weeks, the DP values responded differently between
the fertilizer treatments. The DP value was lowest in the soil that had inorganic NPK and manure, higher in the soil that
received inorganic NPK, manure and lime and it was the highest in unfertilized (control) soil. The soil pH values for these
treatments were 4.47, 5.79 and 6.58, respectively. However, when the soil pHs were adjusted by addition of either H2SO4 or NaOH to give a range between pH 2 and 12, the DP values from all three fertilizer treatments showed almost identical responses.
The optimum pH value for DP was between 7 and 8 for all three fertilizer treatments. Substrate-induced respiration values
from all fertilizer treatments showed a similar trend to DP when the soil pHs were modified. The results show that soil pH
was an important factor which in the studied soils controls the microbial community in general and the community of denitrifiers
in particular. However, denitrifiers showed a high pH resilience leading to no marked change of the pH optimum for potential
denitrification.
Received: 10 September 1998 相似文献