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Net carbon dioxide (CO2) emission from soils is controlled by the input rate of organic material and the rate of decomposition which in turn are affected by temperature, moisture and soil factors. While the relationships between CO2 emission and soil factors are well-studied in non-salt-affected soils, little is known about soil properties controlling CO2 emission from salt-affected soils. To close this knowledge gap, non-salt-affected and salt-affected soils (0-0.30 m) were collected from two agricultural regions: in India (irrigation induced salinity) and in Australia (salinity associated with ground water or non-ground water associated salinity). A subset (50 Indian and 70 Australian soils) covering the range of electrical conductivity (EC) and sodium adsorption ratio (SAR) in each region was used in a laboratory incubation experiment. The soils were left unamended or amended with mature wheat residues (2% w/w) and CO2 release was measured over 120 days at constant temperature and soil water content. Residues were added to overcome carbon limitation for soil respiration. For the unamended soils, separation in multidimensional scaling plots was a function of differences in soil texture (clay, sand), SOC pools (particulate organic carbon (POC) and humus-C) and also EC. Cumulative CO2-C emission from unamended and amended soils was related to soil properties by stepwise regression models. Cumulative CO2-C emission was negatively correlated with EC in saline soils (R2 = 0.50, p < 0.05) from both regions. In the unamended non-salt-affected soils, cumulative CO2-C emission was significantly positively related to the content of POC for the Indian soils and negatively related to clay content for the Australian soils. In the wheat residue amended soils, cumulative CO2-C emission had positive relationship with POC and humus-C but a negative correlation with EC for both Indian and Australian soils. SAR was negatively related (β = −0.66, p < 0.05) with cumulative CO2-C emission only for the unamended saline-sodic soils of Australia. Cumulative CO2-C emission was significantly negatively correlated with bulk density in amended soils from both regions. The study showed that in salt-affected soils, EC was the main factor influencing for soil respiration but the content of POC, humus-C and clay were also influential with the magnitude of influence depending on whether the soils were salt affected or not. 相似文献
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Ambika P. Singh MVSc PhD Gaj Raj Singh MVSc Dwarika N. Sharma MVSc PhD Janki M. Nigam MVSc PhD Amar K. Bhargava MS PhD 《Veterinary radiology & ultrasound》1982,23(6):279-281
Arteriographic anatomy of the major branches of the abdominal aorta of rabbits, dogs, pigs, and goats was investigated. The origin and location of the celiac, cranial mesenteric, right renal, left renal, caudal mesenteric, and external iliac arteries were demonstrated, and their placement was described in relation to the iliac bifurcation and lumbar vertebral bodies. 相似文献
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Water transmission characteristics under saturated and unsaturated conditions were studied in a sandy loam soil with (F1) and without (F0) long-term farmyard manure (FYM) treatments, in relation to sodium adsorption ratios (SAR) and electrolyte concentrations of water. The effect of FYM and ratios of Ca2+ : Mg2+ in water at a given SAR on sodication of the soil was also studied.Saturated hydraulic conductivity (k) and weighted mean diffusivity () were slightly higher for F1 than for F0, whereas sodication indices like Gapon constant (KG), Krishnamoorthy-Davis-Overstreet constant (KKDO) and Vanselow constant (KV) were slightly smaller. The k and decreased with an increase of SAR and decrease of electrolyte concentration, the effect of SAR being more pronounced. There was proportionately a sharper decrease in the k and values at SAR 10 with total electrolyte concentrations of 10–40 meq 1?1. However, with a total electrolyte concentration of 80 meq 1?1, there was a smaller drop at SAR 10.A small difference in the build-up of exchangeable sodium percentage (ESP) in F1 and F0 treatments at a given SAR suggests that, apart from slightly improving water transmission parameters, the use of FYM also reduces the sodication hazard in a soil irrigated with sodic waters. An increase in the Ca2+ : Mg2+ ratio from 25:75 to 75:25 slightly decreased the values of KG, KKDO and KV, thus indicating somewhat more preference for Ca2+ to Mg2+ at a given SAR, which was more so in F1 soil. This fact could also be expressed in terms of a slight shift of thermodynamic exchange constant (K) and standard free energy change of the exchange reaction (ΔG0r). The presence of some unidentified Na+ releasing minerals in the soils studied was observed and correction for exchangeable Na+ determination applied. 相似文献
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A.B.M. Raj 《Research in veterinary science》1994,56(3):81
This study was carried out under commercial conditions to investigate the feasibility of killing turkeys while they were still in their transport containers, with a mixture of gases, and to compare the effects of this method and electrical stunning on the prevalence of carcase downgrading conditions and haemorrhages in the breast muscles. The results showed that turkeys could be readily killed while still in their transport containers by using either anoxia induced with 90 per cent argon in air or hypercapnic anoxia induced with a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, and that the prevalence of carcase-downgrading conditions and haemorrhages in the breast muscles was lower after killing the turkeys with the gases. 相似文献
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Sathyanarayana?Niranjan?Raj Nandini?Prasad?Shetty Hunthrike?Shekar?ShettyEmail author 《Phytoparasitica》2004,32(5):523-527
In an attempt to find a suitable alternative to the otherwise perilous chemical control strategy of disease management, the
amino acid proline was evaluated for its efficiency to elicit resistance in pearl millet (Pennisetum glaucum (L.) R. Br.) against downy mildew disease caused bySclerospora graminicola (Sacc.) Schroet both under greenhouse and field conditions. Proline treatment to seeds at 50 mM concentration for 3 h, significantly
enhanced the seed germination and seedling vigor of pearl millet in comparison with the control. The same concentration and
duration of seed treatment protected the pearl millet plants from downy mildew by offering 58% protection under greenhouse
and 67% protection under field conditions. Studies revealed that 3 days were required for proline-treated plants to develop
resistance, which was systemic and was sustained throughout the life of the plants. Apart from disease protection, proline
was also found effective in enhancing vegetative and reproductive growth of the plants, as evidenced by the increase in height,
fresh weight, leaf area, tillering capacity, 1000-seed weight and grain yield in comparison with the control plants.
http://www.phytoparasitica.org posting Oct. 3, 2004. 相似文献
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Tripathi GR Park J Park Y Hwang I Park Y Hahm KS Cheong H 《Journal of agricultural and food chemistry》2006,54(22):8437-8443
A PVYO virus-resistant potato (Solanum tuberosum L. cv. Golden Valley) was identified, and further, from its tubers, a small (5.57 kDa) antiviral peptide potide-G was isolated. Application of potide-G on virus susceptible potato (cv. Winter valley) expressed robust resistance to PVYO infection and showed no virus infected morphology. We found that PVYO infection spreads up completely within 3 days post inoculation (dpi) in susceptible cultivar. PVYO was more accumulated toward the basal leaves, when infection occurred longer. Combined results of morphology of PVYO infection, ELISA, RT-PCR, and real-time PCR showed the resistance to the PVYO infection depends on the expression of Ry gene. Indeed, the real-time PCR result showed that the Ry gene up-regulated to 3 times higher in PVYO infected cv. Golden valley. Golden crude protein was found to be active against PVYO infection in the in vivo test. In addition, application of potide-G in a virus susceptible potato potently reduced the viral infection actively with 50 times lower concentration than that of the Golden protein. Further identification of a host-specific resistant gene in a plant and the peptide derived from it offers new opportunities for the development of novel bio-pesticides against plant virus. 相似文献
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