Contents Of Nt Research Articles

κ-Opioid Receptors Improve Vascular Endothelial Dysfunction in Salt-Sensitive Hypertension via PI3K/Akt/eNOS Signaling Pathway.

κ-Opioid receptors (κ-OR) are widely used to regulate the activity of the cardiovascular system. To explore the effect and mechanism of κ-OR on salt-sensitive hypertensive endothelial dysfunction, we used Dah1 rats to construct a rat model of salt-sensitive hypertension on a high-salt (HS) diet. Then, the rats were treated with κ-OR activators U50,488H (1.25 mg/kg) and inhibitor nor-BNI (2.0 mg/kg) for 4 weeks, respectively. The rat aortas were collected to detect the contents of NO, ET-1, AngII, NOS, T-AOC, SO, and NT. Protein expression was determined for NOS, Akt, and Caveolin-1. In addition, the vascular endothelial cells were extracted, and the levels of NO, TNF-α, IL-1, IL-6, IL-8, IL-10, p-Akt, and p-eNOS in cell supernatants were detected. In vivo results showed that compared with the HS group, treated with U50,488H promoted rats' vasodilation by increasing the NO content and decreasing ET-1 and AngII contents. U50,488H reduced endothelial cell apoptosis and attenuated vascular, smooth muscle cell and endothelial cell injury. U50,488H also enhanced the rats' response to oxidative stress by increasing the NOS and T-AOC contents. Moreover, U50,488H increased the eNOS, p-eNOS, Akt, and p-AKT expression and decreased the iNOS and Caveolin-1 expression. In vitro results showed that U50,488H promoted NO, IL-10, p-Akt, and p-eNOS levels in endothelial cell supernatants versus the HS group. And U50,488H reduced the adhesion of peripheral blood mononuclear cells and polymorphonuclear neutrophils to endothelial cells and the migration function of polymorphonuclear neutrophils. Our study suggested that κ-OR activation may improve vascular endothelial dysfunction in salt-sensitive hypertensive rats through the PI3K/Akt/eNOS signaling pathway. This may be a potential therapeutic approach in the treatment of hypertension.

Effect of green alder (Alnus viridis) and black alder (Alnus glutinosa) on chemical and microbial properties of sandy mine soils

Various alder species may be used in the reforestation of post-mining barrens in order to supply developing mine soils with nitrogen, increase their organic matter content and biological activity. The objective of this study was to compare the effect of green alder (Alnus viridis) and black alder (Alnus glutinosa) on chemical and microbiological properties of sandy mine soils. The samples of O horizon and mineral soil (0–5 cm) were taken under the equal-aged green and black alder stands growing on extremely poor sands and measured for the contents of organic C (Corg) and total contents of N (Nt), P (Pt), K, Ca and Mg. In the mineral soil, additionally available and water soluble P (Pavl and PH2O) was measured. The measured microbial properties included microbial biomass (Cmic), basal respiration rate (RESP), N mineralization rate (Nmineralization) and the activities of urease (URE), alkaline and acid phosphatase (PHOalk and PHOacd, respectively). The O horizon under black alder contained significantly more nutrients (Nt, Pt, K), harbored higher microbial biomass and exhibited higher basal respiration rate than the O horizon under green alder. In the mineral soil differences between the two alder species were less pronounced. The contents of Corg, Nt, Pt, K and Ca were similar under both alder species. The Cmic and RESP values also did not differ between the alder species. Nevertheless, higher Nmineralization, PHOacd and PH2O content under black alder suggest that this species increases N and P availability in the mine soils to a greater extent than green alder. We conclude that although both alder species contribute to development of mine soils the positive influence of green alder is less compared with black alder.

Influencia de la cobertura, pendiente y profundidad, sobre el carbono y nitrógeno del suelo

El estudio conjunto del carbono orgánico del suelo (COS) y el nitrógeno total del suelo (Nt) es importante debido a que sus ciclos interaccionan, además de que son considerados parámetros de fertilidad, calidad e impacto. Sus contenidos en el suelo inciden en la productividad de los bosques y tienen relación con la mitigación del cambio climático cuando el suelo se conserva. Se realizó un muestreo de suelos en la Estación Forestal Experimental de Zoquiapan, con el objetivo de obtener y analizar el contenido de COS y Nt del suelo a las profundidades de 0 a 10, 10 a 20 y 20 a 30 cm, con tres grados de pendiente donde se desarrollan bosques de oyamel, pino y pino-aile. Los mayores almacenes de COS y Nt se ubicaron en los primeros 10 cm. El suelo con la cobertura de oyamel, pendiente mayor y profundidad menor presentó el mayor contenido de COS y Nt (132.20 y 14.19 Mg ha-1 respectivamente). El suelo con cobertura de pino, pendiente y profundidad mayor tuvo los contenidos más bajos de COS y Nt (30.86 y 3.37 Mg ha-1, respectivamente). Se concluye que los contenidos de COS y Nt mostraron diferencias por tipo de cobertura, por pendiente y por profundidad. Aunque fue con relación a la profundidad que los contenidos de COS y Nt tuvieron un comportamiento más regular, que disminuye a medida que la profundidad se incrementó, independientemente de la cobertura y pendiente.

Efecto del cambio de uso de suelo en el contenido del carbono orgánico y nitrógeno del suelo

Los suelos son el mayor reservorio de carbono, contienen casi tres veces más que la biomasa aérea. Los cambios de uso de suelo representan la segunda fuente antrópica de emisiones a la atmósfera. Se evaluó el contenido de carbono y nitrógeno en cuatro sistemas de uso de suelo: matorral espinoso tamaulipeco, cultivo agrícola, pastizal y plantación de eucaliptos. Se recolectaron cuatro muestras de suelo por sitio, a dos profundidades (0-5 y 5-30 cm); se analizó el contenido de carbono orgánico del suelo (COS), nitrógeno total (Nt) y se estimó la relación C/N. Los resultados del contenido de COS y Nt para la profundidad 0-5 cm fueron de 1.4-0.16 % (agrícola), 2.4-0.27 % (plantación), 3.41-0.33 % (pastizal) y 4.1-0.43 % (matorral), respectivamente. Para la profundidad 5-30 cm, los valores disminuyeron. La relación C/N presentó registros de 8.7 a 10.4, en ambas profundidades; lo que indica una buena humificación de la materia orgánica. Las pérdidas de COS y Nt por los cambios de uso del suelo de matorral a otro sistema fluctuaron de 2.4 % hasta 66 %, el COS se redujo, principalmente, en la profundidad de suelo 0-5 cm; mientras que el Nt tuvo las mayores reducciones en la profundidad de 5-30 cm. Al sistema agrícola le correspondió una pérdida más alta de COS y Nt, en las dos profundidades. Los resultados evidencian que los cambios de uso de suelo ocasionan una disminución en la fertilidad, lo que se refleja en el sistema agrícola, donde los contenidos de C y Nt fueron más bajos, respecto a lo estimado en la vegetación de matorral.

Relación de vegetación ribereña y propiedades del suelo en un afluente del río Tacotalpa, Tabasco, México

La vegetación ribereña ha sido fuertemente fragmentada por acciones antrópicas modificando su estructura y sus funciones ecosistémicas. Se analizaron las variables de vegetación ribereña y su relación con las propiedades del suelo en un afluente del río Tacotalpa, Tabasco. A lo largo del cauce se seleccionaron tres zonas: baja, media y alta; en cada zona se establecieron ocho unidades de muestreo de 5 m × 50 m y se censaron todos los árboles y arbustos con DAP ≥ 1 cm. Se identificaron las especies y se generó información sobre el índice de valor de importancia (IVI), diversidad de especies (H') e índice de similitud (IS). En cada unidad de muestreo se colectó una muestra de suelo a una profundidad de 0 cm -30 cm y se analizaron las propiedades textura, pH, materia orgánica (MO), nitrógeno total (Nt), fósforo asimilable (P) y potasio (K). Las variables se analizaron con los paquetes estadísticos SPSS y PAST. En las tres zonas de vegetación ribereña se registraron 1681 individuos, 38 familias y 131 especies; las familias Fabaceae, Euphorbiaceae y Moraceae fueron las más representativas. La diversidad fue similar en las tres zonas y la similitud osciló entre 31.3% y 53.3%. Los contenidos de Nt, MO y P fueron mayores en suelos de la zona alta con vegetación más conservada y menores en las zonas baja y media con vegetación secundaria; estas variables edáficas se correlacionaron positivamente con la altura de los árboles (p < 0.01), siendo evidente el efecto benéfico de la interacción planta-suelo.

Composition and activity of soil microbial communities in different types of temperate forests

The composition and diversity of forest soil microbial communities may be affected by the composition of plant communities and characteristics of soils. The objective of our study was to compare microbial properties of soils under various types of temperate forests. The samples were taken from soil A horizons under dry and mesic pine forests, acidophilus and fertile beech forests, hornbeam and oak dominated deciduous forests and ash dominated riparian forest. The samples were analysed for pH and the contents of organic C and total N, P, K, Ca, Mg and Mn. Microbial analyses included determination of microbial biomass, basal respiration, community level physiological profiles (CLPPs) measured by MicroResp™ method and phospholipid fatty acid (PLFA) profiles. The soil microbial communities under the pine forests were lower, less active and exhibited different CLPPs and PLFA profiles than those under deciduous forests. The PLFA profiles and CLPPs were correlated to each other revealing that the observed different metabolic abilities under the pine and deciduous forest types resulted from differences in taxonomic composition of soil microbial communities. The CLPPs and PLFA profiles depended on soil texture and the contents of Corg, Nt, and Pt indicating that in the temperate forests the taxonomic and functional composition of soil microbial communities are shaped by both the soil properties and the vegetation. The functional diversity of soil microbial communities was not related to plant diversity indicating that in temperate forests the number of plant species has little effect on the ability of soil microorganisms to degrade different organic compounds.

How Fertilisation Affects Distribution Of Carbon And Nutrients In Vineyard Soil?

Abstract The effect of fertilisation on C and N, P, K nutrients distribution in the Rendzic Leptosol in locality Nitra-Dražovce was studied. We evaluated the following treatments of fertilisation: (1) G (non-fertilised), (2) FYM (farmyard manure – dose 40 t/ha), (3) G+NPK3 (grass + 3rd intensity of fertilisation for vineyards), and (4) G+NPK1 (grass + 1st intensity of fertilisation for vineyards). The soil samples were taken in spring during the years 2008–2015. Obtained results showed that the content of organic carbon (Corg) decreased in the following order: G+NPK1 > FYM > G > G+NPK3 and content of total nitrogen (Nt) decreased in the following order: FYM > G+NPK3 > G+NPK1 > G. The application of NPK in the 1st intensity of fertilisation for vineyards and added FYM build up a Corg at an average rate of 370 and 229 mg/kg/year, respectively. On the other hand, contents of Nt due to fertilisation declined in FYM, G+NPK3 and G+NPK1 at an average rate of 53, 22 and 20 mg/kg/year, respectively. Available P and K contents were also increased after the fertilisation of FYM and NPK. Added fertilisers (G+NPK3) significantly build up a P at an average rate of 10.2 mg/kg/year.

Soil chemical properties affect the reaction of forest soil bacteria to drought and rewetting stress.

Reaction of soil bacteria to drought and rewetting stress may depend on soil chemical properties. The objectives of this study were to test the reaction of different bacterial phyla to drought and rewetting stress and to assess the influence of different soil chemical properties on the reaction of soil bacteria to this kind of stress. The soil samples were taken at ten forest sites and measured for pH and the contents of organic C (Corg) and total N (Nt), Zn, Cu, and Pb. The samples were kept without water addition at 20 – 30 °C for 8 weeks and subsequently rewetted to achieve moisture equal to 50 – 60 % of their maximum water-holding capacity. Prior to the drought period and 24 h after the rewetting, the structure of soil bacterial communities was determined using pyrosequencing of 16S rRNA genes. The drought and rewetting stress altered bacterial community structure. Gram-positive bacterial phyla, Actinobacteria and Firmicutes, increased in relative proportion after the stress, whereas the Gram-negative bacteria in most cases decreased. The largest decrease in relative abundance was for Gammaproteobacteria and Bacteroidetes. For several phyla the reaction to drought and rewetting stress depended on the chemical properties of soils. Soil pH was the most important soil property influencing the reaction of a number of soil bacterial groups (including all classes of Proteobacteria, Bacteroidetes, Acidobacteria, and others) to drought and rewetting stress. For several bacterial phyla the reaction to the stress depended also on the contents of Nt and Corg in soil. The effect of heavy metal pollution was also noticeable, although weaker compared to other chemical soil properties. We conclude that soil chemical properties should be considered when assessing the effect of stressing factors on soil bacterial communities.Electronic supplementary materialThe online version of this article (doi:10.1007/s13213-014-1002-0) contains supplementary material, which is available to authorized users.

Near infrared spectroscopy—A tool for chemical properties and organic matter assessment of afforested mine soils

The objectives of this study were to assess chemical and microbial properties of different post-mining barrens afforested with Scots pine (Pinus sylvestris) and to evaluate the potential of near infrared spectroscopy (NIRS) to predict these properties in the reclaimed soils. The samples were collected from four sites at different substrates and measured for the contents of organic C (Corg), total N (Nt), Corg-to-Nt ratio, dehydrogenase activity, contents of humified C, humic acid C and fulvic acid C, cation exchange capacity, exchangeable acidity, total exchangeable bases (TEB) and base saturation. The spectra of samples were recorded between 400 and 2500nm. A modified partial least squares method with cross-validation was used to develop calibration models for prediction of chemical and microbial properties of the samples from their spectra. There were significant differences in the contents of Corg, Nt, dehydrogenase activity, pH and sorption properties between the mine soils. The samples from the studied sites had different spectral characteristics suggesting differences in chemical composition of their organic matter. “Excellent” predictive models (coefficient of correlation between the predicted and reference values ≥0.90) based on NIR spectra were developed for Nt, Corg-to-Nt ratio, humified C, humic acid C and exchangeable acidity. For other soil properties (except the TEB), “satisfactory” (r=0.80–0.90) models useful for fast screening were developed. The results indicate the potential of NIRS to predict several properties of the reclaimed mine soils.

Tillage-induced changes in the distribution of soil organic matter and the soil aggregate stability under a former short rotation coppice

No-till, perennial cropping in short rotation coppice (SRC) can increase the contents of soil organic carbon (SOC) in arable soils. The return to annual crops will involve an intense tillage, which was hypothesised to accelerate the mineralisation. The impact of tillage on the contents of SOC and of total nitrogen (Nt) and the aggregate stability was investigated at a SRC with 17 years old stools of willows and poplar (Salix and Populus spp.), a tilled former SRC (TFC) and a continuously annually tilled arable soil (TS) at an Eutric Cambisol in Northern Germany in 2010. The contents of SOC and Nt in the topsoil (0–30cm soil depth) decreased in the following order: SOC: SRC (9.1±1.21mgg−1)>TFC (8.2±0.41mgg−1)>TS (6.4±0.0mgg−1) and Nt: SRC (0.94±0.03mgg−1)>TFC (0.86±0.08mgg−1)>TS (0.78±0.07mgg−1). SOC was relatively homogeneously distributed in the topsoil under TFC and TS, but concentrated close to the surface under SRC. The C/N ratio was significantly larger under SRC (9.7±0.40) and TFC (9.5±0.36) than under TS (8.2±0.55). The ratio of water-stable soil aggregates in the size of 2.00–3.15mm decreased in the following order: SRC (60±16%)>TFC (10±5%)>TS (3±1%). Overall the study indicated that tillage of former SRC leads to a fast redistribution of SOC in the topsoil combined with a loss of aggregate stability. The pool size of SOC in the topsoil (SRC 36.7±4.7Mgha−1; TFC 38.1±2.4Mgha−1) remained unchanged after the first year of returned tillage and did not confirm an accelerated mineralisation in the short term. SRC and TFC exceed TS by about 6–8Mgha−1 SOC (TS 30.2±0.0Mgha−1 SOC).

Stabilita organickej hmoty cernozeme a hnedozeme rôznych ekosystémov

In this study, the changes in soil organic matter (SOM) and the possibilities of their monitoring in a shorter period of time by means of carbon parameters were followed. The experiment includes four ecosystems (forest, meadow, urban, and agro-ecosystem) on Haplic Chernozem (Mocenok, Horna Kraľova, Trnava) and Haplic Luvisol (Ludanice, Veľke Zalužie, Lovce) of different localities. The objectives of this study were assessment of the differences in the stability of soil organic matter in different ecosystems and in soil types using labile forms of carbon and nitrogen, and also with dependence on particle size distribution. The highest contents of total organic carbon (TOC) and labile carbon (CL) were in a forest ecosystem, but in case of other ecosystems, the differences were determined only in the contents of CL. After forest ecosystem, the highest content of CL was in agro-ecosystem > meadow ecosystem > urban ecosystem. Based on parameter of lability of carbon (LC), the most labile carbon can be evaluated also in the forest ecosystem (0.209) > agro-ecosystem (0.178) > meadow ecosystem (0.119) and urban ecosystem (0.116). In the case of nitrogen, the differences were observed between the soils. Higher contents of NT and NL were recorded in Haplic Chernozen than in Haplic Luvisol. Contents of TOC (P < 0.05; r = -0.480), CNL (P < 0.05; r = -0.480), and NL (P < 0.01; r = -0.545) were in a negative correlation with the content of sand fraction. The values of studied parameters in meadow and urban ecosystems were relatively balanced, because in both cases, the vegetation cover were grass, pointing to a significant influence of vegetation on the parameters of SOM.

Effect of grazing on wind driven carbon and nitrogen ratios in the grasslands of Inner Mongolia

Wind erosion and dust storms are common phenomena in the semi-arid Xilingele grassland (Inner Mongolia) and contribute considerably to matter balances. Dust emission and dust deposition affect particles of the silt and clay fraction and the organic matter predominantly, the carriers for nutrients in soils. Based on wind erosion measurements in spring 2005 and 2006 the organic carbon and total nitrogen contents of dust were analyzed to determine the contribution of wind erosion processes on C- and N-ratios to the grasslands. Dust deposition is important for the C and N balance in semi-arid grasslands. Despite large differences in dust storm intensities, the Corg and Nt contents in the trapped sediments were in the same range for both years with 35.1–39.1 mg g− 1 (Corg) and 3.23–3.60 mg g− 1 (Nt). These contents were significantly higher than the average soil contents of Corg and Nt, which were 24.5 mg g− 1 and 2.53 mg g− 1, respectively. Grazing intensity was the strongest influencing factor on material gains or losses and was reflected strongly in the vegetation conditions (vegetation height and vegetation coverage). A moderate grazing with 1 to 2 ewes per hectare was the grazing practice, in which dust deposition and dust emission were in equilibrium. Heavy grazing (> 2 ewes per hectare) resulted in average organic carbon and nitrogen losses of 4.8 kg ha− 1 (Corg) and 0.4 kg ha− 1 (Nt) in the spring 2005 and 89.8 kg ha− 1 (Corg) and 8.3 kg ha− 1 (Nt) in the spring 2006. Lightly grazed sites (< 1 ewe per hectare) gained between 14.7 and 52.7 kg ha− 1 Corg and 1.4 to 4.8 kg ha− 1 Nt in 2005 and 129 to 243 kg ha− 1 Corg and 11.9 to 22.3 kg ha− 1 Nt in 2006. The largest matter gain was measured at ungrazed sites with on average 238.9 kg ha− 1 Corg and 20.0 kg ha− 1 Nt in 2006.

Microbial C, N, and P relationships in moisture‐stressed soils of Potohar, Pakistan

AbstractIn 11 rain‐fed arable soils of the Potohar plateau, Pakistan, the amounts of microbial‐biomass C (Cmic), biomass N (Nmic), and biomass P (Pmic) were analyzed in relation to the element‐specific total storage compartment, i.e., soil Corg, Nt, and Pt. The effects of climatic conditions and soil physico‐chemical properties on these relationships were highlighted with special respect to crop yield levels. Average contents of soil Corg, Nt, and Pt were 3.9, 0.32, and 0.61 mg (g soil)–1, respectively. Less than 1% of Pt was extractable with 0.5 M NaHCO3. Mean contents of Cmic, Nmic, and Pmic were 118.4, 12.0, and 3.9 µg (g soil)–1. Values of Cmic, Nmic, Pmic, soil Corg, and Nt were all highly significantly interrelated. The mean crop yield level was closely connected with all soil organic matter– and microbial biomass–related properties, but showed also some influence by the amount of precipitation from September to June. Also the fraction of NaHCO3‐extractable P was closely related to soil organic matter, soil microbial biomass, and crop yield level. This reveals the overwhelming importance of biological processes for P turnover in alkaline soils.

Influence of deer exclusion on soil nutrients in oak forests of a central European low mountain range

High densities of red deer can have severe impacts on soil nutrient status by removing the ground vegetation and enhancing erosion of the fertile soil layers. We compared four fenced deer exclosures with adjacent unfenced sites to evaluate the effect of deer grazing and trampling on the soil nutrient status (Corg, Nt, PO43−, Ca2+, Mg2+, K+) in sloping oak forests of a central European low mountain range. The investigation was set up as a three-factor randomized complete block design (RCBD) with the factors: ‘fencing’ (fenced/unfenced), ‘gradient’ (gentle/steep) and ‘aspect’ (windward/leeward). We hypothesized that exclusion of red deer by fencing would increase soil nutrient contents independent of slope gradient and aspect. Fencing increased the contents of Corg, Nt, Ca2+ and PO43−, but only at the windward sites. This effect was less pronounced at the gently sloping site than at the steep site, which exhibited the lowest contents of Corg, Nt and PO43− of all sites. We did not find increased soil nutrients in the fenced exclosures at the leeward sites, neither at the steep nor at the gently sloping site. At both slope aspects nutrient contents (Corg, Nt, PO43−, K+) tended to be higher on the gentle than at the corresponding steep slopes. Our results suggest that red deer trampling and grazing enhance the loss of soil nutrients at predisposed sites such as windward locations with a high slope gradient. Only at such sites did the exclusion of red deer increase several soil nutrients. Copyright © 2005 John Wiley & Sons, Ltd.

Soil microbiological monitoring of a pine forest after partial thinning for stand regeneration with beech seedlings

A 62 year old pine stand located in northeastern Germany (Brandenburg, Ost-Prignitz, Revier Beerenbusch) was studied with respect to a thinned vs. an unthinned variant. Samples of the litter layer and the top mineral horizon of an acid brown earth were collected from five plots at each variant in April and November during 3 years (2000–2002), respectively. Soil microbial biomass (Cmic and basal CO2 respiration were assayed using an infrared gas analysis system. Soil organic carbon (Core) and total nitrogen (Nt) contents were determined using a C/N elemental analyzer. In addition, cellulose decomposition in soil was assayed using a mini-container system. The contents of Corg, Nt, Cmic and basal respiration activity in the humus layer and in the mineral soil horizon did not differ significantly during 3 years shortly after thinning. Furthermore, no difference was detected comparing spring and autumn samplings of 3 years under study. On the other hand, cellulose decomposition in soil was slightly but not yet significantly increased in the thinned variant. Thus, 3 years after thinning no significant actual impacts on soil ecological properties were detected, but first evidence for increased soil biochemical activities in the thinned variant was found. Long-term monitoring and spatially more detailed analyzes are required to reveal lasting impacts of thinning. Special emphasis needs to be directed on the composition of soil microbial communities and on specific activities related to soil organic matter transformation.

Soil microbial biomass C and N along a climatic transect in the Mongolian steppe

The relationships of soil microbial biomass C (Cmic) or N (Nmic) with mean annual precipitation and temperature were studied along a climatic transect in the Mongolian steppe. Soil organic C (Corg) and total N (Nt), respiration rate, Cmic and Nmic at depths of 0−5 and 5−10 cm decreased with increasing aridity. The contents of Corg and Nt in the 0- to 5-cm soil layers decreased linearly with precipitation reduction along the transect. Cmic and Nmic changes with precipitation were not linear, with higher changes between 330 and 128 mm mean annual precipitation. Cmic/Corg and Nmic/Nt increased with increasing aridity. The metabolic quotient qCO2 of 0- to 5-cm soil layers was low between 330 and 273 mm precipitation. The relationship between the qCO2 of the 0- to 5-cm soil layers and the mean annual precipitation was well fitted with a quadratic function y =0.0006x 2 −0.40x +86.0, where y is the qCO2 (µmol CO2-C mmol−1 Cmic) and x is the mean annual precipitation (mm). Corg, Nt, Cmic, Nmic and respiration rate decreased exponentially with increasing mean annual temperature in both the 0- to 5- and 5- to 10-cm soil layers, and change rate was lower when the mean annual temperature was higher than 2.6°C. The close relationships of the mean annual precipitation or temperature with soil Corg, Nt, Cmic, Nmic, Cmic/Corg and qCO2 indicate that each parameter can be calculated by determining the other parameters in this specific climatic range.

Effect of land management without farmyard manure application on the amount and the ectivity of soil microbial biomass

Four kinds of cereal crops were grown without farmyard manure application. The effect of farmyard manure was supposed to be replaced by post-harvest residues (PH treatment) or by ploughing the total by-product, i.e. straw (PZ treatment) into soil. After seven years of application, this soil farming system did not influence the contents of Cox and Nt in soil. The amount of organic carbon had declined after the first year, but in the following years it remained at the same level (1.2%). The total nitrogen content increased from 0.143 to 0.166% without any considerable difference between the treatments. The amount of microbial biomass (C&lt;sub&gt;mic&lt;/sub&gt;) in PH treatment had been varying and in 2000 it decreased approximately by a half (from 215.96 to 132.00 mg C/kg of soil dry matter). The input of organic matter due to ploughing the whole by-product (PZ treatment) into soil acted favourably and the value of C&lt;sub&gt;mic&lt;/sub&gt; in 2000 was quite comparable with the average values of the individual years of 1994&amp;ndash;1997. This land management and cereal growing caused a reduction of the ratio of microbial biomass carbon to soil organic carbon (C&lt;sub&gt;mic&lt;/sub&gt;/C&lt;sub&gt;org&lt;/sub&gt;). In the year 2000, the values decreased from 2.59 to 1.09% and from 2.88 to 1.82% in PH and PZ treatments, respectively. The amount of the biologically releasable nitrogen (Nbiol) and the intensity of nitrification were the highest in the year 2000. There was a moderate negative correlation (r = &amp;ndash;0.474) between the N&lt;sub&gt;biol&lt;/sub&gt; values and biomass amount values in PZ treatment, and a very close negative one (r = &amp;ndash;0.972) in PH treatment. This relation became strong in both treatments when the values Cmic/Corg and Nbiol were compared, i.e. r&lt;sub&gt;PH&lt;/sub&gt; = &amp;ndash;0.863 and r&lt;sub&gt;PZ&lt;/sub&gt; = &amp;ndash;0.921. The results confirmed that the amount and the quality of organic matter influence microbial biomass and its activity which is responsible for the nutrient release.

Lemon flavonoid, eriocitrin, suppresses exercise-induced oxidative damage in rat liver

To examine the preventive effect of the lemon flavonoid, eriocitrin (eriodictyol 7- O-rutinoside), on oxidative stress during acute exercise in vivo, levels of N ε- (hexanoyl)lysine, HEL; o, o-dityrosine, DT; and nitrotyrosine, NT, as oxidative stress markers, were determined by ELISA in livers of trained rats in addition to thiobarbituric acid-reactive substance (TBARS). Eriocitrin administration prior to exercise significantly suppressed the increases in TBARS caused by lipid peroxidation during acute exercise. The contents of HEL, DT, and NT in rat liver increased dramatically by exercise without eriocitrin administration. However, these increases were significantly suppressed by eriocitrin administration before exercise. Moreover, in this study, to clarify whether eriocitrin influences glutathione metabolite system that is considered to be important for a defense against the damage by oxidative stress, the levels of glutathione in rat liver were determined during exercise. The level of reduced glutathione after exercise was maintained by administration of eriocitrin. The increase in the concentration of oxidized glutathione caused by exercise was significantly suppressed by eriocitrin. This result suggested that eriocitrin might play an important role in the control of the change in glutathione redox status in rat liver during exercise. These findings showed that eriocitrin was effective in the prevention of oxidative damages caused by acute exercise-induced oxidative stress.

Untersuchungen über mikrobiologische, physikalische und chemische eigenschaften türkischer böden und deren beziehungen untereinander

Summary The main part of the analysed 124 Turkish soils are loamy soils with more or less share of sand and clay. All soils contain carbonats (∅ 11.4%). Most of them show a pH value above 7 (∅ 7.34), moderate contents of salts (∅ 0.09%), high contents of K2O (∅ 36mg/100g), lower contents of P2O5 (∅ 15.8 mg/100 g), relative low contents of Nt (∅ 0.116 %) and organic matter (om) (∅ 1.840 %) and a narrow C/N relation (∅ 9.3). Between various properties are found positive correlations: Fig. 1 These correlations are substantially based on the well-known relationships in soil science.