首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 348 毫秒
1.
This study reports distribution of uranium (U) and thorium (Th) in soil samples and the roots and shoots of some plants grown around an abandoned lead (Pb)–zinc (Zn)–copper (Cu) mining area. The plants Euphorbia macroclada, Verbascum cheiranthifolium Boiss, and Astragalus gummifer were examined. The determinations of U and Th were carried out by inductively coupled plasma‐mass spectrometry (ICP‐MS). Uranium and Th levels of the studied soil samples were found to be in the range of 1.1–70.3 mg kg?1 and 2.1–62.1 mg kg?1, respectively. Some results obtained from this study were higher than the mean U and Th concentrations of soils reported around the world. Uranium and thorium concentrations in studied plant roots were in the range of 0.04–16 and 0.08–14.57 mg kg?1, whereas in plant shoots they were 0.02–2.76 and 0.07–12.3 mg kg?1, respectively. It was concluded that the shoots of Astragalus and roots of Euphorbia and Verbascum can be used as both a biomonitor for environmental pollution and biogeochemical indicator because of their higher U and Th concentrations.  相似文献   

2.
The physic nut tree (Jatropha curcas) is an oilseed species with potential for biodiesel production. We evaluated the effect of soil acidity indices on nutrient uptake for optimal growth in physic nut plants grown on acidic soils under greenhouse conditions. Two soils were used in the experiment. Maximum growth was obtained with the application of 1.05 g lime kg-1 for both soils. Maximum growth of the physic nut plants occurred under the following conditions: pH of water = 6.1, calcium (Ca2+) = 17.0 mmolc kg?1, magnesium (Mg2+) = 5.7 mmolc kg?1, acidity saturation = 10.3%, base saturation = 52.3%, Ca saturation = 36.0%, Mg saturation = 12.0% and potassium (K) saturation = 3.8%. Furthermore, the nitrogen (N) requirement of physic nut trees was shown to be high, and to a lesser degree, Ca and Mg requirements were also high, suggesting that liming is very important in crop cultivation of this species.  相似文献   

3.
Abstract

Greenhouse experiment was conducted to evaluate the effect of arbuscular mycorrhizal fungi (AMF) on plant growth, and nutrient uptake in saline soils with different salt and phosphorus (P) levels. The following treatments were included in this experiment: (i) Soil A, with salt level of 16.6 dS m?1 and P level of 8.4 mg kg?1; (ii) Soil B, with salt level of 6.2 dS m?1 and P level of 17.5 mg kg?1; and (iii) Soil C, with salt level of 2.4 dS m?1 and P level of 6.5 mg kg?1. Soils received no (control) or 25 mg P kg?1 soil as triple super phosphate and were either not inoculated (control) or inoculated with a mixture of AM (AM1) and/or with Glomus intraradices (AM2). All pots were amended with 125 mg N kg?1 soil as ammonium sulfate. Barley (Hordeum vulgar L., cv. “ACSAD 6”) was grown for five weeks. Plants grown on highly saline soils were severely affected where the dry weight was significantly lower than plants growing on moderately and low saline soils. The tiller number and the plant height were also lower under highly saline condition. The reduced plant growth under highly saline soils is mainly attributed to the negative effect of the high osmotic potential of the soil solution of the highly saline soils which tend to reduce the nutrient and water uptake as well as reduce the plant root growth. Both the application of P fertilizers and the soil inoculation with either inoculum mixture or G. intraradices increased the dry weight and the height of the plants but not the tiller number. The positive effect of P application on plant growth was similar to the effect of AM inoculation. Phosphorus concentration in the plants was higher in the mycorrhizal plant compared to the non mycorrhizal ones when P was not added. On the other hand, the addition of P increased the P concentration in the plants of the non mycorrhizal plants to as high as that of the mycorrhizal plants. Iron (Fe) and zinc (Zn) uptake increased with AM inoculation. The addition of P had a positive effect on micronutrient uptake in soil with low level of soil P, but had a negative effect in soil with high level of soil P. Micronutrient uptake decreases with increasing soil salinity level. Inoculation with AMF decreases sodium (Na) concentration in plants grown in soil of the highest salinity level but had no effect when plants were grown in soil with moderate or low salinity level. The potassium (K) concentration was not affected by any treatment while the K/Na ratio was increased by AM inoculation only when plant were grown in soil of the highest salinity level.  相似文献   

4.
Potassium (K) is one of the major essential nutrient elements whose application of organic or nano-chelate-fertilizers has received increased attention recently. Cadmium (Cd) contamination in agricultural soils and environment is increasing due to the over-application of Cd-containing phosphate fertilizers. But few studies have been carried out on the environmental influences of K-nano-chelate fertilizers especially on Cd-polluted soils. Therefore, the effects of K-fertilizer application in different rates (0, 100 and 200 mg kg?1 soil) and forms (KCl, K2SO4 and K-nano-chelate) on Cd content and partitioning in Ocimum basilicum grown on an artificially Cd-contaminated calcareous soil (with 40 mg Cd kg?1 soil) were studied under greenhouse conditions. Cadmium decreased shoot dry weight (SDW), but did not affect root dry weight (RDW) and no consistent trend was observed with applied K. Cadmium increased shoot and root Cd concentration or uptake. KCl and K2SO4 increased shoot Cd concentration compared to that of control, whereas K-nano-chelate did not affect it. In Cd-treated soils the mean value of Cd translocation factor (ratio of Cd concentration in shoots to that of roots) decreased by 60% as compared to that of the control. Application of 100 mg K-K2SO4 and 100 and 200 mg K-nano-chelate increased the Cd translocation factor by 49, 59 and 112% in Cd-treated soils, respectively. In Cd-treated soils, greater amounts of Cd accumulated in roots. K-nano-chelate could mitigate the adverse effect of Cd on SDW and Cd accumulation in plants grown on Cd-polluted soils, so the risk of Cd entrance to the food chain is reduced (however, in Cd-untreated soils, K-nano-chelate increased the Cd translocation factor higher than other K sources). In Cd-polluted soils KCl was the most inappropriate fertilizer that may intensify Cd accumulation in plants. However, it may be useful in the phytoremediation of Cd-polluted soils.  相似文献   

5.
The effects of inoculating arbuscular mycorrhizal (AM) fungi on the growth, phosphorus (P) uptake, and yield of Welsh onion (Allium fistulosum L.) were examined under the non-sterile field condition. Welsh onion was inoculated with the AM fungus, Glomus R-10, and grown in a glasshouse for 58?days. Non-inoculated plants were grown as control. Inoculated and non-inoculated seedlings were transplanted to a field with four available soil P levels (300, 600, 1,000, and 1,500?mg P2O5?kg?1 soil) and grown for 109?days. AM fungus colonization, shoot P concentration, shoot dry weight, shoot length, and leaf sheath diameter were measured. Percentage AM fungus colonization of inoculated plants was 94% at transplant and ranged from 60% to 77% at harvest. Meanwhile, non-inoculated plants were colonized by indigenous AM fungi. Shoot length and leaf sheath diameter of inoculated plants were larger than those of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Shoot P content of inoculated plants was higher than that of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Yield (shoot dry weight) was higher for non-inoculated plants grown in soil containing 1,000 and 1,500?mg P2O5?kg?1 soil than for those grown in soil containing 300 and 600?mg?P2O5 kg?1 soil. Meanwhile, the yields of inoculated plants (200?g plant?1) grown in soils containing the four P levels were not significantly different. Yield of inoculated plants grown in soil containing 300?mg P2O5 kg?1 soil was similar to that of non-inoculated plants grown in soil containing 1,000?mg P2O5?kg?1 soil. The cost of AM fungal inoculum for inoculated plants was US$ 2,285?ha?1 and lower than the cost of superphosphate (US$ 5,659?ha?1) added to soil containing 1,000?mg P2O5 kg?1 soil for non-inoculated plants. These results indicate that the inoculation of AM fungi can achieve marketable yield of A. fistulosum under the field condition with reduced application of P fertilizer.  相似文献   

6.
Copper/zinc bioaccumulation and the effect of phytotoxicity on the growth of lettuce (Lactuca sativa L.) were studied in plastic vessels containing (i) non-contaminated soil, (ii) copper-contaminated soils at concentrations of 75.0 and 125.0 mg kg?1, (iii) zinc-contaminated soils at concentrations of 1200 and 2400 mg kg?1, and (iv) soil enriched with swine manure. Copper and zinc concentrations in lettuce leaves were determined by flame atomic absorption spectrometry during 42 days of growth. Copper concentrations from 0.92 to 13.06 mg kg?1 were found in lettuce leaves grown in copper-contaminated soils and zinc concentrations from 58.13 to 177.85 mg kg?1 were found in lettuce leaves grown in zinc-contaminated soils. Copper and zinc concentrations in lettuce leaves grown in swine manure-enriched soils ranged from 0.82 to 8.33 and 0.68 to 13.27 mg kg?1, respectively. Copper and zinc bioaccumulation caused a decrease in lettuce growth in metal-contaminated soils and an increase in phytotoxicity effects when compared to growth in non-contaminated and manure-enriched soils. These findings were confirmed by measuring leaf areas and biomasses. Copper was less toxic to lettuce than zinc due to the different concentrations in the soil. Lettuce growth and development was better in the swine manure-enriched soil than non-contaminated soil, which indicates that swine manure is a safe agricultural biofertilizer when used in appropriate amounts to avoid metal bioaccumulation in soil and plants.  相似文献   

7.
The phytoremediation potential for Pb of Buddleja asiatica (a wild species) and a closely related cultivated species, B. paniculata, was investigated by means of field survey, hydroponic and pot experiments, and field trial experiments. Field surveys showed that B. asiatica had an extraordinary accumulation capacity and tolerance for Pb. Plants grown in soil with 2,369.8–206,152 mg kg?1 total Pb accumulated 1,835.5–4,335.8 mg kg?1 Pb in their shoots. Under hydroponic conditions (10, 20 mg l?1 Pb), both B. asiatica and B. paniculata showed unusually high concentrations of Pb in their roots (12,133–21,667 mg kg?1) and increased biomass production. A pot experiment in a greenhouse without any soil amendments was conducted on three different soils with various Pb contents (10,652, 31,304, 89,083 mg kg?1) for 3 months. The results showed that both species of Buddleja had an increase in the biomass similar to the control plants. There was a slight decrease in survival rates of plants grown in soil with 89,083 mg kg?1 Pb content. A field trial experiment was conducted for 6 months at three sites around the Pb mine area in which plants were provided with Osmocote fertilizer. Both Buddleja species showed 100% survival, increased biomass production and phytoextraction capacity (TF 1.1–2.3) when grown in soil with Pb content of 94,584–101,405 mg kg?1. Plants accumulated 2,273–3,675 mg kg?1 Pb in their shoots. The results suggest these Buddleja plants are suitable for use in the phytoremediation of Pb-contaminated soil.  相似文献   

8.
Leaching of nutrients in soil can change the surface and groundwater quality. The present study aimed at investigating the effects of raw and ammonium (NH4+)-enriched zeolite on nitrogen leaching and wheat yields in sandy loam and clay loam soils. The treatments were one level of nitrogen; Z0: (100 kg (N) ha?1) as urea, two levels of raw zeolite; Z1:(0.5 g kg?1 + 100 kg ha?1) and Z2: (1 g kg?1 + 100 kg ha?1), and two levels of NH4+-enriched zeolite; Z3: (0.5 g kg?1 + 80 kg ha?1) and Z4: (1 g kg?1 + 60 kg ha?1). Wheat grains were sown in pots and, after each irrigation event, the leachates were collected and their nitrate (NO3?) and NH4+ contents were determined. The grain yield and the total N in plants were measured after four months of wheat growth. The results indicated that the amounts of NH4+ and NO3? leached from the sandy loam soil were more than those from the clay loam soil in all irrigation events. The maximum and minimum concentrations of nitrogen in the drainage water for both soils were observed at control and NH4+-zeolite treatments, respectively. Total N in the plants grown in the sandy loam was higher compared to plants grown in clay loam soil. Also, nitrogen uptake by plants in control and NH4+-zeolite was higher than that of raw-zeolite treatments. The decrease in the amount of N leaching in the presence of NH4+-zeolite caused more N availability for plants and increased the efficiency of nitrogen fertilizers and the plants yield.  相似文献   

9.
Sodium (Na) and calcium (Ca) in brackish water differentially affects boron (B) nutrition of plants grown on calcareous and salt-affected soils. A glasshouse experiment was conducted to evaluate the effect of brackish irrigation water with different sodium adsorption ratio (SARiw) [distilled-water control, 8, and 16 (mmolc L?1)1/2] on B nutrition of maize. Plants were grown for 40 days with 5 levels of B (0, 1.29, 2.30, 3.22, and 4.46 mg kg?1 soil). Boron application significantly improved plant growth at lower rates. High B rates and application of high SARiw decreased plant growth independently, and the reduction in growth was further aggravated due to combined effect of both B and high SARiw. Decreased growth was attributed mainly to increased shoot B and Na concentration, while decreased Ca concentration. These ionic changes also altered internal and external B requirements. Yield decrease was observed at lower B concentration in soil solution B and plants shoot grown with high SARiw than in plants grown with distilled water and low B application rates.  相似文献   

10.
Environmental concern due to plant accumulation of natural radionuclides is a major concern in uranium mining areas. To evaluate the risk associated with the transfer of radionuclides to edible plants, the uptake of 238U, 226Ra, and 210Pb by Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) grown in soils contaminated with uranium-mill tailings (UMT) was investigated. Test plants were grown under controlled conditions in substrate composed of soil and UMT in different ratios. Activity concentrations of 238U, 226Ra, and 210Pb in substrate, leaves, and roots were measured and the concentration ratios determined. Soil characteristics were determined, since they directly affect bioavailability of radionuclides. Concentration ratios of 238U, 226Ra, and 210Pb in leaves varied from 0.001 to 0.006, 0.024 to 0.172, and 0.004 to 0.011, respectively, and in roots from 0.020 to 0.126, 0.015 to 0.241, and 0.033 to 1.460, respectively. Concentrations of 238U, 226Ra, and 210Pb in leaves and roots were found to correlate with the amount of 238U, 226Ra, and 210Pb in the substrate. A higher amount of 226Ra accumulated in aboveground parts (57–877 Bq kg?1 d. m. for leaves) compared to 238U (0.6–4.7 Bq kg?1 d. m. for leaves) and 210Pb (8–53 Bq kg?1 d. m. for leaves), which were mainly stored in the roots. The relationships between the amount of radionuclides in plants and soil characteristics and their role in radionuclide uptake are discussed and critically evaluated.  相似文献   

11.
The distribution in soil and plant uptake of zinc (Zn) and lead (Pb) as influenced by pine bark-goat manure (PBG) compost additions were investigated from the soils artificially contaminated with Zn or Pb ions using maize (Zea mays L.) as a test crop. Soils were amended with four rates of pine bark-goat manure compost (0, 50, 100, and 200 tons ha?1) and four rates (0, 300, 600 and 1200 mg kg?1) of Zn or Pb. Maize was planted and grown for 42 days. At harvest, plants samples were analyzed for Zn and Pb concentration. Soils samples were analyzed for pH, extractable and diethylene triamine pentaacetic acid (DTPA) extractable Zn and Pb. Extractable Zn and Pb was lower in PBG compost amended soils than in unamended soils and steadily declined with increasing amount of compost applied. The extractable fraction for Zn dropped by 62.2, 65.0 and 44.6% for 300, 600 and 1200 mg Zn kg?1, respectively when 200 t ha?1 of PBG compost was applied. Metal uptake by maize plants were directly related to the rate of applied heavy metal ions with greater concentrations of metals ions found where metal ions were added to non-amended soils.  相似文献   

12.
High levels of phosphorus (P) often induce zinc (Zn) deficiency in plants grown on Zn-poor soils. We investigated P-induced Zn deficiency in durum wheat (Triticum durum L. ‘Carpio’) grown on 16 noncalcareous and 31 calcareous soils differing in levels of available (Olsen) P and available (diethylenetriaminepentaacetic acid (DTPA)-extractable) Zn using micropots. A completely randomized factorial design with two levels of P (0 and 40 mg P kg?1 soil) and Zn (0 and 3 mg Zn kg?1 soil), i.e. four treatments (‘control’, + P, + Zn, and + PZn), were used. Grain yield of control plants depended mainly on the Olsen P level. Phosphorus had a negative effect on yield in 6 soils with Olsen P/ZnDTPA > 25, and Zn a positive one in 5 soils with Olsen P/ZnDTPA > 50; and the + PZn treatment generally resulted in the highest yield. Grain Zn concentration of control plants was negatively correlated with growth and Olsen P. Calcareous soils were less sensitive to P-induced Zn deficiency than noncalcareous soils because phosphate is sorbed by calcite rather than being co-adsorbed with Zn on the Fe oxides. Co-application of P and Zn to soil at low and application of Zn at high Olsen P ensured both maximum yield and grain Zn bioavailability.  相似文献   

13.
Abstract

Athyrium yokoscense, a type of fern that grows vigorously in mining areas in Japan, is well known as a Cd hyperaccumulator as well as a Cu, Pb and Zn tolerant plant. However, no information is available on As accumulation of A. yokoscense, although it often grows on soils containing high levels of both heavy metals and As. In this study, young ferns collected from a mine area were grown in media containing As-spiked soils or mine soil in a greenhouse for 21 weeks. Athyrium yokosense was highly tolerant to arsenate and survived in soils containing up to 500 mg As (V) kg?1. The addition of 100 mg As (V) kg?1 resulted in the highest fern biomass (1.95 g plant?1) among As-spiked soils. Although the As concentration of the fern was lower than other As hyperaccumulators, such as Pteris vittata, A. yokoscense could hyperaccumulate As in mature and old fronds. Arsenic was accumulated most efficiently in old fronds (922 mg kg?1) in the media containing 5 mg As (III) kg?1. Moreover, higher As accumulation was found in the roots of the ferns, with a range from 506 to 2,192 mg kg?1. In addition, in the mine soil with elevated concentrations of As and heavy metals, A. yokoscense not only hyperaccumulated As (242 mg As kg?1 in old fronds), but also accumulated Cd, Pb, Cu and Zn at concentrations much higher than those reported for other terrestrial plants. Athyrium yokoscense accumulated Cd mostly in fronds in high concentrations, up to 1095 mg kg?1, while it accumulated Cu, Zn and Pb mainly in the roots and the concentrations were 375, 2040 and 1165 mg kg?1, respectively.  相似文献   

14.
A pot experiment evaluated the growth of lettuce (Lactuca sativa L.) and barley (Hordeum vulgar) and accumulation of molybdenum (Mo) in plants and soils following amendments of Mo compost (1.0 g kg?1) to a Truro sandy loam. The treatments consisted of 0 (control), 12.5, 25, and 50% Mo compost by volume. The Mo compost did not affect dry‐matter yield (DMY) up to 25% compost, but DMY decreased at the 50% compost treatment. The 50% compost treatments increased the soil pH an average of 0.5 units and increased the nitric acid (HNO3)–extractable Mo to 150 mg kg?1 and diethylenetriaminepentaacetic acid (DTPA)–extractable Mo to 100 mg kg?1 in the growth medium; the same treatment increased tissue Mo concentration to 569 and 478 mg kg?1 in the lettuce and barley, respectively. Plants grown in the 25% compost produced about 55 mg kg?1 of total Mo in the growth medium; this resulted in tissue Mo concentration of 348 mg kg?1 in lettuce and 274 mg kg?1 in barley without any phytotoxicity. Our results suggested that 55 mg Mo kg?1 soil would be an appropriate limit for Mo loading of soil developed from compost additions, a value which is presently greater than the Canadian Council for Ministers of the Environment (CCME) Guidelines for the use of type B compost in Canada.  相似文献   

15.
A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg?1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg?1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg?1 soil is recommended for maize performance improvement.  相似文献   

16.
Accurate estimation of the available potassium (K+) supplied by calcareous soils in arid and semi‐arid regions is becoming more important. Exchangeable K+, determined by ammonium acetate (NH4OAc), might not be the best predictor of the soil K+ available to crops in soils containing micaceous minerals. The effectiveness of different extraction methods for the prediction of K‐supplying capacities and quantity–intensity relationships was studied in 10 calcareous soils in western Iran. Total K+ uptake by wheat grown in the greenhouse was used to measure plant‐available soil K+. The following methods extracted increasingly higher average amounts of soil K+: 0.025 M H2SO4 (45 mg K+ kg?1), 1 M NaCl (92 mg K+ kg?1), 0.01 M CaCl2 (104 mg K+ kg?1), 0.1 M BaCl2 (126 mg K+ kg?1), and 1 M NH4OAc (312 mg K+ kg?1). Potassium extracted by 0.01 M CaCl2, 1 M NaCl, 0.1 M BaCl2, and 0.025 M H2SO4 showed higher correlation with K+ uptake by the crop (P < 0.01) than did NH4OAc (P < 0.05), which is used to extract K+ in the soils of the studied area. There were significant correlations among exchangeable K+ adsorbed on the planar surfaces of soils (labile K+) and K+ plant uptake and K+ extracted by all extractants. It would appear that both 0.01 M CaCl2 and 1 M NaCl extractants and labile K+ may provide the most useful prediction of K+ uptake by plants in these calcareous soils containing micaceous minerals.  相似文献   

17.
Inhibition of nitrification as a mitigation tool to abate nitrogen (N) losses and improve N use efficiency (NUE) is a promising technology. Nitrification inhibitor (dicyandiamide, DCD) was evaluated in two consecutive wheat-maize rotations (2015–2017), with two different N fertilizer levels applied in wheat (160, 220 kg N ha?1) and maize (180, 280 kg N ha?1). More NH4+-N contents (101% and 102% in wheat and 74% and 73% in maize) and less NO3–-N contents (37% and 43% in wheat and 46% and 57% in maize) were observed at both N levels treated with DCD compared to without DCD. Higher pH, lower EC and reduced NO3–-N accumulation were the other benefits of DCD. The NO3–-N accumulation within the 0–200 cm soil profile was significantly less at both N levels with DCD (66 mg kg?1 and 121 mg kg?1) compared to without DCD (96 mg kg?1 and 169 mg kg?1). Application of DCD also improved the growth and yield in both crops. Increase in NUE from 38% to 49% in wheat and 27% to 33% in maize with DCD at higher N level was also observed. Overall, the effectiveness of DCD in retarding the nitrification process was higher in wheat than maize.  相似文献   

18.
Interactions between Zn and Cd on the accumulation of these metals in coontail, Ceratophyllum demersum were studied at different metal concentrations. Plants were grown in nutrient solution containing Cd (0.05–0.25 mg l?1) and Zn (0.5–5 mgl?1). High concentrations of Zn caused a significant decrease in Cd accumulation. In general, adding Cd solution decreased Zn accumulation in C. demersum except at the lowest concentration of Zn in which the Zn accumulation was similar to that without Cd. C. demersum could accumulate high concentrations of both Cd and Zn. The influence of humic acid (HA) on Cd and Zn accumulation was also studied. HA had a significant effect on Zn accumulation in plants. 2 mg l?1 of HA reduced Zn accumulation at 1 mg l?1 level (from 2,167 to 803 mg kg?1). Cd uptake by plant tissue, toxicity symptoms and accumulation at 0.25 and 0.5 mg l?1, were reduced (from 515 to 154 mg kg?1 and from 816 to 305 mg kg?1, respectively) by addition of 2 mg l?1 of HA. Cd uptake reached a maximum on day 9 of treatment, while that of Zn was observed on day 15. Long-term accumulation study revealed that HA reduced toxicity and accumulation of heavy metals.  相似文献   

19.
We investigated the potential of soil moisture and nutrient amendments to enhance the biodegradation of oil in the soils from an ecologically unique semi-arid island. This was achieved using a series of controlled laboratory incubations where moisture or nutrient levels were experimentally manipulated. Respired CO2 increased sharply with moisture amendment reflecting the severe moisture limitation of these porous and semi-arid soils. The greatest levels of CO2 respiration were generally obtained with a soil pore water saturation of 50?C70%. Biodegradation in these nutrient poor soils was also promoted by the moderate addition of a nitrogen fertiliser. Increased biodegradation was greater at the lowest amendment rate (100 mg N kg?1 soil) than the higher levels (500 or 1,000 mg N kg?1 soil), suggesting the higher application rates may introduce N toxicity. Addition of phosphorous alone had little effect, but a combined 500 mg N and 200 mg P kg?1 soil amendment led to a synergistic increase in CO2 respiration (3.0×), suggesting P can limit the biodegradation of hydrocarbons following exogenous N amendment.  相似文献   

20.
ABSTRACT

To establish a critical limit in soils and plant, an experiment was conducted in red and lateritic soil (Alfisols) of farmer’s field in tribal-dominated Panchayat Kurum, Palkot block, Gumla district, Jharkhand, India. Based on the results of the field experiment, the critical limits were determined as 0.48, 0.50, 0.47, and 0.42 mg kg?1 in the soil, respectively, for hot water, hot calcium chloride, salicylic acid, and ammonium acetate-extractable B, while a critical limit of 12.00 mg kg?1 was observed in maize tissue using the graphical method. In an analysis of variance method, the critical limits of B in soils were found as 0.45, 0.54, 0.49, and 0.43 mg kg?1 using hot water, hot calcium chloride, salicylic acid, and ammonium acetate extractants, respectively. Maize plants were highly responsive to B application where soil B level was below the critical limit (0.50 mg kg?1). In a field experiment, grain yield of maize increased with increasing levels of B application, while soil application at 1.0 kg ha?1 + two foliar application (at the knee and pre-flowering stages) of borax at 0.2% were showed significantly higher grain yield of the maize crop. The hot water, hot calcium chloride, salicylic acid, and ammonium acetate-extractable B were significantly and positively correlated with organic carbon and negatively correlated with the electrical conductivity of soils.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号