Concentration and stock of carbon in the soils affected by land uses and climates in the western Himalaya,India

Soils are the third biggest sink of carbon on the earth. Hence, suitable land uses for a climatic condition are expected to sequester optimum atmospheric carbon in soils. But, information on how climatic conditions and land uses influence carbon accumulation in the soils on the Himalayan Mountains is not known. This study reports the impact of four climatic conditions (sub-tropical, altitude: 500–1200 m; temperate 1200–2000 m; lower alpine 2000–3000 m; upper alpine, 3000–3500 m) and four land uses (forest, grassland, horticulture, agriculture) on the concentrations and stocks of soil organic carbon (SOC) in upper (0–30 cm) and deeper (30–100 cm) soil depths on the western Himalayan Mountains of India. The study also explored the drivers which influenced the SOC stock build up on the mountains. Rainfall and soil moisture showed quadratic relations, whereas temperature declined linearly with the altitude. SOC stock as well as concentration was the highest (101.8 Mg ha^− 1 in 0–30 cm, 227.97 Mg ha^− 1 in 0–100 cm) in temperate and the lowest in sub-tropical climate (37 Mg ha^− 1 in 0–30 cm, 107.04 Mg ha^− 1 in 0–100 cm). Pattern of SOC stock build up across the altitude was: temperate > lower alpine > upper alpine > sub-tropical. SOC stocks in all land uses across the climatic conditions, except agriculture in lower alpine, was higher (0.7 to 41.6%) in the deeper than upper soil depth. SOC stocks in both the depths showed quadratic relations with soil temperature and soil moisture. Other factors like fine soil particles, land-use factor and altitude influenced positively whereas slope and pH, negatively to the SOC stocks. In all climatic conditions, other than temperate, SOC stocks were greater in natural ecosystems like forests and pastures (112.5 to 247.5 Mg ha^− 1) than agriculture (63 to 120.4 Mg ha^− 1). In temperate climate, SOC stock in agriculture (253.6 Mg ha^− 1) on well formed terraces was a little higher than forest (231.3 Mg ha^− 1) on natural slope. These observations, suggest that land uses on temperate climate may be treated as potential sinks for sequestration of the atmospheric carbon. However, agriculture in subtropical climate need to be pursued with due SOC protection measures like the temperate climate for greater sequestration of the atmospheric carbon.     

营林措施对沙地樟子松人工林土壤养分、酶活性及微生物量碳的影响

在科尔沁沙地南缘章古台地区,对采用3种营林措施的樟子松人工林土壤养分、酶活性和微生物量碳进行测定分析,结果表明:2001围封处理区除速效钾外其它测定指标都低于对照区和同龄2007年围封处理区,2001围封+间伐处理区与其它处理相比,除全磷、速效钾和中性磷酸酶外,其它指标显著提高;32年生林分已修枝7年的樟子松人工林,随修枝强度的增大,土壤脲酶活性和微生物量碳增加,土壤过氧化氢酶和中性磷酸酶活性及土壤养分含量下降;40年生左右的樟子松人工林,通过卫生伐改造成疏林处理区与对照区相比,土壤养分含量、酶的活性和微生物量碳显著提高。研究认为沙地樟子松人工林地力衰退可通过营林措施加以控制,关键要合理经营。     

锡林河流域羊草群落春季CO2排放日变化特征分析

利用静态暗箱法对具有代表性的典型温带草原的羊草群落CO2排放进行了昼夜观测。结果表明,CO2排放通量日变化与气温和地表温度呈明显的正相关关系,相关系数分别为0.7475和0.7604,而与5cm和10cm地温相关性较小,说明在干旱半干旱草原地区气温和地表温度是影响羊草群落CO2排放的关键性因子。研究还发现,羊草群落排放的CO2的近80%来自土壤呼吸、根呼吸和凋落物分解,并且春季露水对羊草草原CO2排放通量日变化特征影响显著,特别是日出前后露水的大量形成,使上午7～8时出现一次CO2排放峰值,而后CO2排放通量变化趋于与气温一致。     

High Temperature Influence 14CO2 Assimilation and Allocation of 14C into Different Biochemical Fractions in the Leaves of Indian Mustard

Influence of high temperature stress on photosynthesis and allocation of carbon into different biochemical fractions in mature leaves of Indian mustard [ Brassica juncea (L) Czern] was investigated. Heat stress reduced ¹⁴CO₂ fixation and inhibited the translocation of carbon from the leaves. Allocation of ¹⁴C into starch and residue fractions was significantly lower in heat stressed plant leaves. Starch content was significantly reduced in heat stressed plants.     

Effect of Whole Season CO2 Enrichment on the Cultivation of a Medicinal Plant, Digitalis lanata

A versatile method was developed for the application of 1000 ppm CO₂ during the whole growth period of plants. Temperature controlled water cooling and ventilation of the greenhouse resulted in a monthly CO₂ enrichment time of 60 to 90 % of the total light period. Digitalis lanata , grown in greenhouses with CO₂ enrichment during the whole growth phase from April to November, produced twice as much biomass as field cultivated plants.
The relative yield of the glycoside digoxin per gram Digitalis drug dry weight was 0.4% in field grown and 0.7% in greenhouse cultivated plants. The production of digoxin per hectare in the greenhouse at 1000 ppm CO₂ was almost 3.5-fold that by field cultivation. Drug yield and secondary metabolite production in D. lanata were remarkably influenced by increased temperature and elevated CO₂ partial pressure in the greenhouse.     

The role of field studies in landscape-scale applications of process models: an example of soil redistribution and soil organic carbon modeling using CENTURY

Field studies on soil properties and processes in southern Saskatchewan have clearly indicated the need to account for both lateral and vertical transfers of components in the landscape for a better understanding of soil dynamics at a given point. Extrapolation of these studies requires greater integration of the site-specific field results with the current generation of process models. In this paper, we use the results of a field study to assess the ability of the CENTURY model to describe the influence of soil redistribution on soil organic carbon (SOC) dynamics. After modifying the erosion input of CENTURY to account for soil deposition, the results from CENTURY were compared to measured SOC levels from a chronosequential study of cultivation effects on SOC levels in southern Saskatchewan. CENTURY closely simulated the effects of soil loss on SOC levels in landform segments with dominantly convex profile (i.e., downslope) curvature. CENTURY estimates of SOC changes for landform segments experiencing soil gain are less comparable to the field results; it overestimated SOC loss after 80 years by 16 Mg ha⁻¹ for depressional complexes and 10 Mg ha⁻¹ for footslope complexes. This leads to a 14% difference in total SOC loss on a landscape-weighted basis (estimated loss based on field data of 36 Mg ha⁻¹ versus a CENTURY-simulated loss of 41 Mg ha⁻¹).     

Alteration of serum free fatty acids during the carbon tetrachloride-induced fatty liver in rats

AIM: To investigate the alteration of serum free fatty acids in the carbon tetrachloride-induced fatty liver. METHODS: Drug-induced fatty liver rat models were built by injection 40% CCl₄. Serum free fatty acids were analyzed by gas chromatography. RESULTS: In the composition of serun free fatty acids, polyunsaturated fatty acids[oleic acid C18:1,(28.672±7.332/mg·L^-1 vs 41.373±2.180/mg·L^-1),linoleic acid C18:2(16.739±0.871/mg·L^-1 vs 24.959±5.325/mg·L^-1),arachidonic acid C20:4(6.105±2.656/mg·L^-1 vs 9.802±0.779/mg·L^-1),P<0 05], were decreased significantly, but saturated fatty acids [lauric acid C12：0(3.368±0.330/mg·L^-1 vs 2.742 0.351/mg·L^-1),myrist ic acid C14:0(27.136 3.158/mg·L^-1 vs 16.152±0.638/mg·L^-1),palmitic acid C16:0(51.731±9.561/mg·L^-1 vs 34.522±1.401/mg·L^-1),P<0 05] increased. CONCLUSION: Serum polyunsaturated fatty acids were decreased and saturated fatty acids increased in the drug-induced fatty liver.     

乌拉苔草湿地土壤CO2和CO的变化特征

对乌拉苔草湿地生长季节内土壤CO2和CO的变化特征进行了模拟研究。结果表明:生长季节的乌拉苔草湿地土壤释放CO2,并消耗CO。化学反应CO H2O→CO2 H2对于CO2和CO的动态变化起主要作用,CO2和CO之间存在显著的负相关。温度对CO2和CO体积分数的影响存在一定差异,但差异不显著。     

Tomato Fusarium wilt suppressiveness. The relationship between the organic plant growth media and their microbial communities as characterised by Biolog

Fusarium wilts are economically important diseases for which there are no effective chemical control measures. Biological control strategies are becoming efficient alternatives for controlling this disease. The suppressiveness to Fusarium oxysporum f. sp. lycopersici race 1 of grape marc compost and cork compost was evaluated in comparison to peat by using a susceptible cultivar of tomato (Lycopersicon esculentum cv. Marmande). Based on community level physiological profiles, different community structures were evident among the plant growth media evaluated. The peat microbial community, growth medium conducive to wilt, used mostly sugars, while those associated with both composts, the very suppressive grape marc and the moderately suppressive cork, used mostly carboxylic acids, amino acids, amines, phenolic compounds and polymers.     

锥形喷管出口结构对热烟雾机动力性能的影响

通过对不同出口直径喷管出口燃气压力与流速、燃油消耗等参数的测试、对比与分析，研究了喷管出口结构对烟雾机工作性能的影响，结果表明：将直喷管出口段改为渐放型锥形喷管后，烟雾机动力性能没有降低，且有利于减小积炭。