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21.
Aggregate associated carbon, nitrogen and sulfur and their ratios in long-term fertilized soils 总被引:3,自引:0,他引:3
Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka−1 and high level of 60 Mg ka−1) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1–2 mm) and microaggregates (<0.106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5–1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5–1 and <0.106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher C/N, C/S and N/S ratios were found both in large dry aggregates (>20 and 6–20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0.106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered. 相似文献
22.
Borbála D. Harrach József Fodor Miklós Pogány Jutta Preuss Balázs Barna 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(1):21-33
Leaves of powdery mildew-susceptible barley (Hordeum vulgare cv. Ingrid) and related near-isogenic lines bearing various resistance genes (Mla12, Mlg or mlo5) were inoculated with Blumeria graminis f. sp. hordei race A6. Fungal attack induced several-fold increases in ethylene emission and electrolyte leakage in leaves of susceptible
Ingrid beginning 3 days after inoculation. Activities of peroxidase, superoxide dismutase, glutathione S-transferase, ascorbate peroxidase and glutathione reductase enzymes were induced markedly in susceptible leaves 5–7 days
after inoculation. Similar, but less pronounced pathogen-induced changes were detected in inoculated leaves of Mla-type resistant
plants that show hypersensitive cell death upon inoculation, and, to an even lesser extent, in the Mlg and mlo lines, where
no visible symptoms accompanied the incompatible interaction. Glutathione content increased only in susceptible barley 7 days
after inoculation. Catalase activity, total ascorbate content and redox state were not influenced by inoculation in any of
the genotypes. The activity of dehydroascorbate reductase was significantly reduced 3–5 days after inoculation in the susceptible
parental plants and after 5 days in Mla and Mlg lines, while it was stable in the mlo barley. Slightly elevated levels of
H2O2 were observed in the inoculated resistant plants. In contrast, H2O2 content decreased in the susceptible line 7 days after pathogen attack. These data indicate that high levels of antioxidants
are involved in the compatible interaction of susceptible barley and powdery mildew by protecting the pathogen from oxidative
damage. 相似文献
23.
Soil pH, soil organic matter (SOM), dissolved organic carbon (DOC) and total trace metal concentration (M(tot)) control the solubility of metals in the soil. Several regression models have included these soil chemical variables for the prediction of metal solubility and free metal ion (FMI) concentrations in contaminated soils. We hypothesize that models developed on contaminated soils (after optimization of the coefficients) can be used on samples from uncontaminated sites. Soil samples were collected from unpolluted agricultural and forest soils located in Eastern Croatia and extracted with water to determine the concentrations of Cd, Cu, Pb and Zn. We used these data to test the applicability of three regression models on existing conditions under different land uses. The same predictors issued in the three models and the same regression coefficients were utilized in the present study. The results showed a good correlation between the observed and predicted values of metal solubility. However, the models overestimate the total solution concentration (M(sol)) and the concentrations of free metal ions (FMI) in solution, and therefore the same regression coefficients were optimized to fit our own observations. This was found to be very successful. The results showed that pH and DOC played a very important role in controlling metal solubility, while SOM and CEC were somewhat less significant. The impact of total soil concentration of metals (M(tot)) was rather minor. However, we feel that to carry out good predictions of M(sol) and FMI, the M(tot) is needed in such regression models. 相似文献
24.
Traditional seed management and genetic diversity in barley varieties in high-hill agro-ecosystems of Nepal 总被引:1,自引:0,他引:1
Jwala Bajracharya Anthony H. D. Brown Bal K. Joshi Dipak Panday Bimal K. Baniya Bhuwon R. Sthapit Devra I. Jarvis 《Genetic Resources and Crop Evolution》2012,59(3):389-398
Chawali and Lekali are two common farmer’s barley varieties or landraces in Jumla, Nepal (2,240–3,000 m) with small to bold
grains and wide adaptation from irrigated low lands to high hills. This study was undertaken to test whether features of the
traditional seed system can significantly influence the diversity of a crop and its conservation on-farm. In Jumla (high-hill),
the barley seed system is completely informal and is mainly from farmer to farmer. In the present study, the seed flows and
the pattern of genetic diversity in barley were investigated to detect differences between the two varieties and test the
divergence among populations of each variety These data suggested that Chawali, the more common variety, was less subject
to homogenising gene flow between farms than was Lekali. A total of 128 farming households were surveyed for seed supply information
and 128 populations for each landrace from two villages: Kartikswami and Talium were collected for SSR diversity analysis.
Some 92 SSRs were screened in an initial sample of 20 barley populations of both landraces and 2 improved varieties (LG-51
and Soluwa). Of the 81 SSRs that consistently amplified, only 15 SSRs (19%) were polymorphic with gene diversity values ranging
from 0.09 to 0.71. A medium to low diversity was detected among the landrace populations of barley varieties. Chawali populations
were less polymorphic within ecological groups, and more divergent between than were Lekail populations. This result accords
with Chawali having a more conservative local seed system. 相似文献
25.
Abul Kashem Bal Ram Singh 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):134-139
Abstract The distribution of DTPA-extractable Cd, Ni and Zn in four profile samples collected from areas contaminated with wastes from tannery, city sewage, pharmaceutical and paper mills located at different places in Bangladesh was investigated. Soil samples were analysed for the total and their DTPA-extractable metal contents. The total concentration of metals in the soil horizons ranged from 0.07 to 0.62 mg kg?1 for Cd, 31 to 54 mg kg?1 for Ni and 59 to 838 mg kg?1 for Zn, respectively. These metal concentrations were highest in the surface and lowest in the subsurface horizons. This trend was also observed for the DTPA-extractable amounts of these metals. The relative extractability, expressed as the ratio of DTPA to total contents (aqua regia-extractable) was 33 to 46% for Cd, 2 to 10% for Ni and 3 to 28% for Zn, respectively, in the A1 horizon, while in the B and C horizons the ratios decreased gradually as did total concentration, indicating that metal contamination was primarily limited to the surface horizon. For all three metals, the above mentioned ratio was highest in the city sewage soil and the lowest in the paper mill soil. In general, the extent of contamination among the profiles investigated was in the following order: city sewage>tannery>pharmaceutical>paper mill soil. Higher ratios of DTPA-extractable Cd, Ni and Zn in the city sewage soil than the other soils may create a risk for the contamination of agricultural products and ground water. 相似文献
26.
Water, Air, &; Soil Pollution - A study was conducted to investigate the heavy metal contamination of soil and vegetation in the vicinity of industries around Dhaka city in Bangladesh.... 相似文献
27.
Effects of road transportation on metabolic and immunological responses in Holstein heifers 下载免费PDF全文
Hyeok‐Joong Kang In Kyu Lee Min‐Yu Piao Chae‐Won Kwak Min Jeong Gu Cheol Heui Yun Hyun‐Jin Kim Hyeon‐Ju Ahn Hee‐Bal Kim Gyeom‐Heon Kim Soo‐Ki Kim Jong‐Youl Ko Jong K. Ha Myunggi Baik 《Animal Science Journal》2017,88(1):140-148
This study examined the effects of road transportation on metabolic and immunological responses in dairy heifers. Twenty Holstein heifers in early pregnancy were divided into non‐transported (NT; n = 7) and transported (T; n = 13) groups. Blood was collected before transportation (BT), immediately after transportation for 100 km (T1) and 200 km (T2), and 24 h after transportation (AT). The T heifers had higher (P < 0.05) blood cortisol and non‐esterified fatty acid concentrations after T1 and T2 than did NT heifers. By contrast, the T heifers had lower (P < 0.05) serum triglyceride concentrations after T1 and T2 than had the NT heifers. The serum cortisol and triglyceride concentrations returned (P > 0.05) to the BT concentrations at 24 h AT in the T heifers. The granulocyte‐to‐lymphocyte ratio and the percentage of monocytes were higher (P < 0.05) after T2 in the T heifers than in the NT heifers, suggesting that transportation stress increased the numbers of innate immune cells. T heifers had higher (P < 0.01) plasma haptoglobin concentrations than NT heifers 24 h AT. In conclusion, transportation increased cortisol secretion and was correlated with increased metabolic responses and up‐regulation of peripheral innate immune cells in dairy heifers. 相似文献
28.
Steven L Stockham Kerry S Keeton Balázs Szladovits 《Veterinary Clinics of North America: Small Animal Practice》2003,33(6):1335-1357
The four major types of leukocytoses are inflammatory, glucocorticoid-associated, catecholamine-associated, and neoplastic. These leukocytoses are distinguished by leukocyte concentrations, microscopic features of leukocytes, and associations with other laboratory data. All laboratory findings need to be interpreted within the context of the case information, including signalment, history, and physical examination findings. Newer assays are being used to differentiate the different forms of leukocyte neoplasia and to distinguish between hyperplastic and neoplastic proliferations. 相似文献
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