Values Of Organic Matter Research Articles

Vis/NIR spectroscopic measurement of selected soil fertility parameters of Cuban agricultural Cambisols

The conventional methods frequently used in Cuba to determine some fertility parameters important for sugarcane production, such as organic matter (OM), available phosphorus (P) and potassium (K2O), are difficult, costly, and time-consuming procedures. This study was undertaken to build and validate Visible/Near Infrared Reflectance (Vis/NIR) calibration models of these parameters at landscape level and within a field, by taking into consideration their correlation coefficients with the OM. The parameters P and K2O, which are not spectrally active in the Vis/NIR range should be better predicted when are highly correlated with OM. Also, the wavelength intervals to simplify this methodology were selected. Samples were air-dried before scanning using a diode array spectrophotometer covering the wavelength range from 399 to 1697 nm. The regression models were built by using the linear multivariate regression method Partial Least Squares (PLS), and the nonlinear multivariate regression methods Support Vector Machines (SVM) and Locally Weighted Regression (LWR). At landscape level the best correlations between soil spectra and OM (0.90 ≤ R2 ≤ 0.93; 0.12 ≤ RMSEP≤0.14) were obtained with LWR, followed by K2O with LWR (0.77 ≤ R2 ≤ 0.79; 3.47 ≤ RMSEP≤3.62), Olsen P (0.69 ≤ R2 ≤ 0.81; 0.27 ≤ RMSEP≤0.35) and Oniani P (0.64 ≤ R2 ≤ 0.65; 3.31 ≤ RMSEP≤3.61) both with SVM. Also, the nonlinear regression models gave the best results within a field. The higher values for OM (R2 = 0.92; RMSEP = 0.14) and Olsen P (0.68 ≤ R2 ≤ 0.83; 0.27 ≤ RMSEP≤0.34) were observed with SVM, while for K2O (0.16 ≤ R2 ≤ 0.63; 5.13 ≤ RMSEP≤5.88), and Oniani P (0.70 ≤ R2 ≤ 0.72; 2.32 ≤ RMSEP≤2.52) were obtained with LWR. The soil fertility parameters studied at landscape level and within a field were best estimated by using nonlinear regression models.

Canopy influences of five range plant species on the redistribution of chemical forms of iron in a calcareous soil

Iron (Fe) deficiency is common in calcareous soils of southern Iran. Chemical forms of Fe in a calcareous soil were studied in the beneath and the interspace soils of five common range plant species. Results showed that electrical conductivity (EC) and organic matter (OM) content was significantly higher in the soil beneath canopies as compared to interspace soil. The reverse was true for pH of the soil except in case of Salvia compressa. Among different forms of Fe, soluble and exchangeable Fe (SolEx-Fe) form was higher in the soil beneath canopy of all plant species as compared to interspaces. Similar results were recorded for Fe bound to organic materials (Om-Fe) but only in the case of Convolvulus argyracanthus, Echinops glanduloso-punctatus, and Centaurea intricata.In the soil beneath Convolvulus argyracanthus and Centaurea intricata canopies Fe bound to manganese (Mn) oxides (Mnox-Fe) was significantly higher but the amount of residual Fe (Res-Fe) was lower compared to the interspace soil. A reverse trend was, however, observed in the case of Teucrium polium, demonstrating differential distribution of Fe forms at the two locations. The summation of reactive Fe forms [SolEx-Fe, Fe bound to carbonates (Car-Fe), and Om-Fe] known as readily or potentially available Fe was higher in the soil under canopies than in interspace soils. It is assumed that the higher contents of OM and lower values of pH enhanced Fe availability in the soil under plant canopies in comparison with interspace soil.

Stable carbon isotope biogeochemistry of propionate and acetate in methanogenic soils and lake sediments

In anoxic environments, degradation of organic matter (OM) results in strong fractionation of carbon isotopes, with formation of 13C-depleted CH4. Propionate and acetate are important products of OM fermentation. Propionate is further fermented to acetate. Acetate is a direct precursor of CH4, the remainder usually being produced from H2-mediated CO2 reduction. There is a paucity of data for the turnover of acetate and, even more so, propionate. We therefore analyzed the δ13C values of organic carbon, propionate, acetate and the methyl (Me) group of acetate (acetate-Me) during the production of CH4 in anoxic incubations of various flooded and non-flooded soils and various lake sediments. Incubation in the presence of CH3F, which inhibits CH4 production from acetate, allowed exclusion of isotope effects during aceticlastic methanogenesis. Despite the variation inherent in the wide diversity of sample type and origin, the data collectively showed that the δ13C value of acetate was only marginally different (−2±5‰) from that of OM, while propionate was depleted in 13C relative to total acetate (−6±5‰). Acetate-Me was generally depleted in 13C relative to total acetate (−8±5‰). Thus, isotopic enrichment factors during the degradation of OM to total propionate and acetate were much smaller than those during hydrogenotrophic and aceticlastic methanogenesis or the intramolecular difference in δ13C between the carboxyl (CO2H) and Me of acetate, so that the δ13C value of OM may be used as a proxy when data for acetate are not available.

Stable Nitrogen Isotopes (<i>δ</i><sup>15</sup>N) in Podetias of Lichenized Fungi <i>Cladonia pocillum</i> from Different Altitudes of Habitats

The δ15N values of stable nitrogen isotopes were determined in samples of organic matter (OM) of podetias of lichen Cladonia pocillums (Ach.) Grognot, collected across 10 altitudinal levels within the range of 1550 - 2900 m.a.s.l. of both steppes and highland meadows of the Khangai Mountains (Mongolia). No correlation between the δ15N values of lichen OM and the altitude range was detected at the regional scale. However, there is a positive correlation δ15N values in OM C. pocillums with of the nitrogen content in the podetias.

Environmental controls on organic matter production and transport across surface-subsurface and geochemical boundaries in the Edwards aquifer, Texas, USA

Karst aquifer phreatic zones are energy limited habitats supported by organic matter (OM) flow across physical and geochemical boundaries. Photosynthetic OM enters the Edwards Aquifer of Central Texas via streams sinking along its northeastern border. The southeastern boundary is marked by a rapid transition between oxygenated freshwaters and anoxic saline waters where OM is likely produced by chemolithoautotrophic microbes. Spatial and temporal heterogeneity in OM composition at these boundaries was investigated using isotopic and geochemical analyses. δ13C values for stream fine particulate OM (FPOM) (−33.34‰ to −11.47‰) decreased during regional drought between fall 2010 and spring 2012 (p<0.001), and were positively related to FPOM C:N ratios (r2=0.47, p<0.001), possibly due to an increasing contribution of periphyton. Along the freshwater-saline water interface (FWSWI), δ13CFPOMvalues (−7.23‰ to −58.18‰) correlated to δ13C values for dissolved inorganic carbon (δ13CDIC) (−0.55‰ to −7.91‰) (r2=0.33, p=0.005) and were depleted relative to δ13CDIC values by 28.44‰, similar to fractionation values attributed to chemolithoautotrophic carbon fixation pathways using DIC as the substrate. δ13CFPOMvalues also became enriched through time (p<0.001), and δ13CDIC values (r2=0.43, p<0.001) and δ13CFPOM values (r2=0.35, p=0.004) at FWSWI sites increased with distance along the southwest-northeast flowpath of the aquifer. Spatial variability in FWSWI δ13CDIC values is likely due to variable sources of acidity driving carbonate dissolution, and the temporal relationship is explained by changes to recharge and aquifer level that affected transport of chemolithoautotrophic OM across the FWSWI.Keywords: Carbon stable isotopes, spatial and temporal variability, chemolithoautotrophic production, allochthonous input, karst.DOI: 10.3986/ac.v42i2-3.666

Nutritional value and chemical composition of pastures of peanut forage or red clover

With this study, we aimed at evaluating the nutritional value and chemical composition of forage legume intercropping with elephant grass (EG) + spontaneous growth species (SGS) + annual ryegrass (AR) + peanut forage (PF), as treatment T1; and EG + SGS + AR + red clover (RD), as T2. The EG was planted in 4- m spaced rows. The annual ryegrass was planted between the EG rows during the cool season; the RC was sowed and the PF was preserved. The experiment was performed between October 2009 and April 2010, with six grazing cycles. Samples of forage legume was collected, under simulated the grazing, to determine the levels of organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), organic matter in situ digestibility (OMISD), total phenols (TF), total tannins (TT), and condensed tannins (CT). The mean values of OM, CP, NDF, OMISD, TF, TT and TC were 90.8, 20.96, 48.38, 86.68, 1.92, 1.42 and 1.39%; and 91.84, 21.41, 41.36, 85.18, 1.90, 1.31 and 0.17% for peanut forage and red clover, respectively. Higher values (p ≤ 0.05) were observed in the level of CT of peanut forage.

Spread of Alsidium corallinum C. Ag. in a Tyrrhenian eutrophic lagoon dominated by opportunistic macroalgae

In 2007, the Rhodophyceae Alsidium corallinum C. Ag., a marine taxon, bloomed in the eutrophic lagoon of Orbetello (Tuscany, Italy) for the first time, becoming the dominant species in spring and summer. In November, its biomass collapsed. The hypothesis examined in this study is that the bloom expressed a relatively low eutrophic level of the ecosystem after intense disposal of accumulated sedimentary organic matter (OM) by dystrophic processes in the two years preceding the bloom. To verify the hypothesis, we compared water physical–chemical variables, sediment redox (Eh) and OM, and standing crops of macroalgae and seagrass from the database of routine monitoring between 2005 and 2008. We also used dissolved nutrient data obtained in 2007 and 2008, as well as data on chlorophyll and total suspended matter in the water column during the microalgal bloom of 2007, and C, N and P content in thalli of the Chlorophycea Chaetomorpha linum and the Rhodophyceae Gracilariopsis longissima and A. corallinum obtained in 2007.In 2007, unusually low values of dissolved inorganic nitrogen (DIN) were recorded. Combined with stable values of soluble reactive phosphorus (SRPs), low DIN led to a reduction of about one order of magnitude in the DIN:SRP atomic ratio with respect to the past and to 2008. G. longissima accumulated C, N and P more than the other species and A. corallinum proved to be less demanding. Sediment OM was lower in the autumn of years characterized by dystrophy, confirming that summer dystrophic events coincided with maximum energy dissipation in this ecosystem. However, as soon as OM and DIN values increased (2008), the vegetation shifted towards blooms of G. longissima and C. linum, while A. corallinum almost disappeared. The results sustain the hypothesis that the bloom of A. corallinum was due to a decline in DIN that limited G. longissima, and to intense turbidity of the water caused by microphytes that developed after the dystrophic event of summer 2006. The latter probably limited the development of C. linum, which could only develop at the edges of the lagoon.

KECERNAAN IN SACCO HIJAUAN LEGUMINOSA DAN HIJAUAN NON- LEGUMINOSA DALAM RUMEN SAPI PERANAKAN ONGOLE

<p>This study was aimed to explore the optimum potential of forage and the degradation rate the rumen of nutrient of forage (legume and non legume) derived different forage fodder used farmers. Seven forages i.e. Gliricidia (GL),<br />Manilkara (SW), Sesbania (TP), Ficus (BR), Calothyrsus (KL), Jackfruit (NG), and Cacao leaves (CO), were used in this experiment. Samples were incubated in the rumen of fistulated cattle with different time intervals, namely 2, 4, 8,<br />12, 16, 24, 36, and 48 hours. The collected data were the nutrient digestibility residues in rumen, including dried matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Data<br />were analyzed using Completely Randomized Design (CRD). From the calculation of in sacco rumen, it was obtained the degradation theory (DT) values of DM : GL 60.06%; SW 34.78%; TP 73.96%; BR 41.40%; KL 43.80%; NG 43.67%; and CO 28.67%. From in sacco rumen calculation, it was obtained the DT values of OM : GL 59.13%; SW 32.74%; TP 73.07%; BR 42.83%; KL 44.18%; NG 45.04%; and CO 26.80%. Calculation of in sacco rumen showed the DT values of CP : GL 66.14%; SW 32.49%; TP 81.46%; BR 42.89%; KL 31.84%; NG 47.05%; and CO 29.46%. The calculation of in sacco rumen, it was obtained the DT values of NDF: GL 46.84%; SW 46.59%; TP 56.69%; BR 44.18%; KL 23.01%; NG 30.07%; and CO 55.43%. From the calculation of in sacco rumen, it was obtained the DT<br />values of ADF: GL 61.27%; SW 43.95%; TP 56.53%; BR 40.11%; KL 21.08%; NG 44.66%; and CO 69.15%. There were significant differences (P<0.05) on the degradation of DM, OM, CP, NDF, and ADF. It is concluded that not all of legume has higher DT values of DM, OM, CP, NDF, and ADF fraction than non-legume. There is a tendency that the longer retention time in the rumen, the higher degradation rate.</p><p>(Keywords: Legume, Non-legume, In sacco rumen)<br /><br /></p>

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

Sediment cores from Lone Spruce Pond (60.007°N, 159.143°W), southwestern Alaska, record paleoenvironmental changes during the global Last Glacial Maximum (LGM), and during the last 14,500 calendar years BP (14.5 cal ka). We analyzed the abundance of organic matter, biogenic silica, carbon, and nitrogen, and the isotope ratios of C and N, magnetic susceptibility, and grain-size distribution of bulk sediment, abundance of alder shrub (Alnus) pollen, and midge (Chironomidae and Chaoboridae) assemblages in a 4.7-m-long sediment sequence from the depocenter at 22 m water depth. The basal unit contains macrofossils dating to 25–21 cal ka (the global LGM), and is interpreted as glacial-lacustrine sediment. The open water requires that the outlet of the Ahklun Mountain ice cap had retreated to within 6 km of the range crest. In addition to cladocerans and diatoms, the glacial-lacustrine mud contains chironomids consistent with deep, oligotrophic conditions; several taxa associated with relatively warm conditions are present, suggestive of relative warmth during the global LGM. The glacial-lacustrine unit is separated from the overlying non-glacial lake sediment by a possible disconformity, which might record a readvance of glacier ice. Non-glacial sediment began accumulating around 14.5 cal ka, with high flux of mineral matter and fluctuating physical and biological properties through the global deglacial period, including a reversal in biogenic-silica (BSi) content during the Younger Dryas (YD). During the global deglacial interval, the δ13C values of lake sediment were higher relative to other periods, consistent with low C:N ratios (8), and suggesting a dominant atmospheric CO2 source of C for phytoplankton. Concentrations of aquatic faunal remains (chironomids and Cladocera) were low throughout the deglacial interval, diversity was low and warm-indicator taxa were absent. Higher production and air temperatures are inferred following the YD, when bulk organic-matter (OM) content (LOI 550 °C) increased substantially and permanently, from 10 to 30 %, a trend paralleled by an increase in C and N abundance, an increase in C:N ratio (to about 12), and a decrease in δ13C of sediment. Post-YD warming is marked by a rapid shift in the midge assemblage. Between 8.9 and 8.5 cal ka, Alnus pollen tripled (25–75 %), followed by the near-tripling of BSi (7–19 %) by 8.2 cal ka, and δ15N began a steady rise, reflecting the buildup of N and an increase in denitrification in soils. Several chironomid taxa indicative of relatively warm conditions were present throughout the Holocene. Quantitative chironomid-based temperature inferences are complicated by the expansion of Alnus and resulting changes in lake nutrient status and production; these changes were associated with an abrupt increase in cladoceran abundance and persistent shift in the chironomid assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.

Stable nitrogen isotopes (d15N) in thalli of arid vagrant lichen Xanthoparmelia camtschadalis across an altitudinal gradient of the Khangai Plateau of Mongolia

The d15N values of stable nitrogen isotopes were determined in samples of organic matter (OM) of thalli of vagrant lichen Xanthoparmelia camtschadalis collected across 13 altitudinal levels within the range of 1550–3250 m above sea level of both steppes and highland meadows of the Khangai Plateau of Mongolia. No correlation between the d15N values of lichen OM and the altitude range was detected at the regional scale. However, at a local scale including vegetation type, botanical-geographical area of Khangai, and mountain slope, the amount of the 15N heavy isotope in lichen OM was found to be decreased with an altitude increase.

Rumen degradability characteristics of normal maize stover and silage, and quality protein maize silage-based diets offered to cows

Rumen degradability characteristics of dry matter (DM), organic matter (OM) and crude protein (CP) of normal maize (NM) stover (T1)-, NM silage (T2)- and quality protein maize (QPM) silage (T3)-based diets were studied using three rumen-fistulated Boran × Friesian non-lactating cows (371 ± 32.00 kg) in 3 × 3 Latin Square Design. Cows were supplemented with a similar concentrate mix. In sacco degradability of DM and OM indicated that the (a) values of DM (128) and OM (114) for NM stover were lower (P < 0.001) than that for NM silage (268 and 253) and for QPM silage (323 and 303), respectively. The (a) value for CP was lower (P < 0.05) for QPM silage (286) than for NM stover (404) and NM silage (326). The (b) values of DM in NM stover (597) and NM silage (535) were higher (P < 0.05) than in QPM silage (499). The (b) value of CP in NM stover (372) was lower (P < 0.05) than in NM silage (655) and in QPM silage (608). Rate of degradation of OM in NM stover and NM silage, each with 0.03, was faster (P < 0.01) than in QPM silage (0.02). Moreover, QPM silage had higher potentially degradable fraction for DM (821) (P < 0.05) and OM (840) (P < 0.01) than DM (725) and OM (712) in NM stover. The mean rumen ammonia concentration (209 mg/l) of QPM silage was higher (P < 0.05) than that of NM stover (179 mg/l) and NM silage (170 mg/l). The average rumen pH (6.1) in cows fed QPM silage was lowest (P < 0.05) compared to pH (6.3) in cows fed either NM stover or silage. The concentration of total volatile fatty acids (116 mmol/l) in the rumen of cows incubated with QPM silage was higher (P < 0.001) than in those incubated with NM stover (113 mmol/l) and NM silage (110 mmol/l). It was concluded that QPM silage-based diet was superior in DM and OM degradability, and had higher ammonia and VFA concentration than NM stover-based diet. No differences have been observed in all parameters measured between QPM and NM silages.

Chemical composition, rumen degradability and crude protein fractionation of some commercial and improved cowpea (Vigna unguiculata L. Walp) haulm varieties

AbstractSeasonal chemical composition, in sacco organic matter (OM) and crude protein (CP) degradabilities and CP fractions of haulms of three improved (ITA2, ITA6 and ITA8) and three commercial (Oloyin, Peu and Sokoto) cowpea varieties harvested in wet and dry seasons were evaluated in a 2 × 2 factorial arrangement of treatments. Effective degradation of OM and CP was estimated at assumed outflow rates of 2 and 4% h−1. Commercial haulms (all the other parts of the cowpea minus the grains) had greater (P &lt; 0·001) CP than improved varieties, whereas neutral detergent fibre and acid detergent fibre were greater (P &lt; 0·001) in improved vs. commercial haulms. Interactions between variety group (improved vs. commercial) and season were observed for CP (P = 0·002), lignin (P = 0·003) and hemicellulose (P = 0·030) contents of the haulms. Similarly, a group × season interaction was observed for effective degradation of OM at an outflow rate of 2%. The proportion of substrate degraded in the samples harvested in the wet season was generally less (P &lt; 0·001) than in the dry season. Effective degradability values of OM at the assumed passage rates were greater (P &lt; 0·001) for improved vs. commercial cowpea haulms. Interactions between group and season were observed for all but one of the CP fractions. Seasonal differences in the quality of haulms showed that attention must be given to handling of haulms to minimize the amount of leaves lost during the wet season.

Evidence for bias in C/ N, δ13C and δ15N values of bulk organic matter, and on environmental interpretation, from a lake sedimentary sequence by pre-analysis acid treatment methods

There is a known bias in C/ N, δ 13 C and δ 15 N values of organic matter (OM) due to pre-analysis acid treatment methods. We report here, for the first time, the results of a pre-analysis acid treatment method comparison of measured C/ N, δ 13 C and δ 15 N values in bulk OM from a sedimentary sequence of samples to illustrate this bias. Here we show that acid treatment significantly reduces the accuracy (between method biases) and precision (within method bias) of C/ N, δ 13 C and δ 15 N values of OM, suggesting a differential response of sample OM between methods and sample horizons, and in some cases inefficient removal of inorganic carbon. We show that different methods can significantly influence environmental interpretation in some of our sample horizons (i.e. interpretation of aquatic vs. terrestrial OM source; C 3 vs. C 4 vegetation). Specifically, there are unpredictable and non-linear differences between methods for C/ N values in the range of ∼1–100; δ 13 C values in the range of 0.2–6.8‰ and; δ 15 N values in the range of 0.3–0.7‰. Importantly, these ranges are mostly much greater than the instrument precision (defined as the standard deviation of replicate analysis of standard reference materials; for this study, ±0.5 for C/ N values, ±0.1‰ for δ 13 C values and; ±0.1‰ for δ 15 N). The accuracy and precision of measured C/ N, δ 13 C and δ 15 N values of bulk OM is not just dependent upon environmental variability, but on acid pre-treatment, residual inorganic carbon and organic matter state and composition. Collectively, this makes the correlation between samples prepared in different ways, including those from down-core reconstructions, highly questionable.

Influence of aquatic macrophytes on the stable carbon isotopic signatures of sedimentary organic matter in lakes on the Tibetan Plateau

Using a set of surface sediment samples and corresponding macrophytes from the Tibetan Plateau, we show that aquatic macrophytes strongly influence the carbon isotope values of organic matter (OM), both total organic carbon (TOC) and compound specific, in lake sediments, which is often neglected when these proxies are interpreted in palaeoenvironmental studies. Assessments on the basis of a binary isotopic model revealed an average contribution from submerged macrophytes of up to 60% (mean 40%) to TOC and up to 100% (mean 66%) to mid-chain n-alkanes (C 23 and C 25). Submerged aquatic macrophytes contained typical mid-chain dominated n-alkane patterns in most of the samples, but also synthesized higher relative amounts of long chain homologues in shallower lakes – possibly due to adaptation to partial exposure to air. Macrophytes showed wide ranges of δ 13C values for bulk OM (−18.1 to −5.8‰) and n-alkanes (e.g. −25.2 to −13.3‰ for n-C 25 in Potamogeton) because of bicarbonate metabolism in the alkaline lakes. There is a highly significant correlation between δ 13C values of lipids and bulk biomass in plant samples, but the offset between the two parameters increases with increasing value for the bulk biomass. In most of the sediment samples, the OM was strongly influenced by aquatic macrophytes, with respect to both n-alkane patterns and δ 13C values. Wide ranges of values for TOC were observed (−29.0 to −16.0‰) as well as for mid-chain n-alkanes (e.g. −34.1 to −16.6‰ for n-C 25), while the variability in long chain n-alkanes (C 27, C 29, C 31) was relatively small. Our results further indicate that, in regions where C 4 vegetation is absent, the relative contribution of submerged macrophytes to sediments can, in addition to n-alkane patterns, be assessed quantitatively from sedimentary δ 13C values.

Valor nutricional de forragem de pastagens manejadas durante o período hibernal

O objetivo nesta pesquisa foi avaliar o valor nutritivo, determinando-se a matéria orgânica (MO), digestibilidade in vitro da MO (DIVMO), nutrientes digestíveis totais (NDT), digestibilidade in vitro da matéria seca (DIVMS), proteína bruta (PB) e fibra em detergente neutro (FDN), de quatro sistemas forrageiros (tratamentos), pastejados por vacas da raça Holandesa. Os tratamentos foram constituídos por "coastcross" (Cynodon dactylon L. Pers.) sobresemeada com azevém (Lolium multiflorium Lam. cv. 'Comum'); coastcross sobresemeada com azevém e trevo branco (Trifolium repens L., cv. 'Yi'); azevém mais trevo branco e apenas azevém. Entre 15 de maio e 24 de outubro de 2006, foram conduzidos cinco ciclos de pastejo, sendo avaliada a massa de forragem de pré-pastejo (MF), as composições botânica e estrutural e lotação (L). Para análise do valor nutritivo, foram coletadas amostras de pastejo simulado. O delineamento experimental foi inteiramente casualizado com quatro tratamentos e duas repetições (piquetes). Não foram detectadas diferenças entre os tratamentos para as médias de MF e L. Observou-se que os melhores resultados de valor nutritivo estão associados à biomassa de lâmina foliar de azevém em todas as pastagens. Verificaram-se pequenas diferenças no valor nutritivo entre as pastagens sobresemeadas em comparação ao azevém e trevo branco ou azevém. Os valores médios de MO, DIVMO, NDT, DIVMS, PB e FDN das pastagens foram de 89,52; 69,50; 60,95; 70,96; 23,03 e 51,87%, respectivamente.

Nutrient and Chemical Properties of Aging Golf Course Putting Greens as Impacted by Soil Depth and Mat Development

Nutrient and chemical changes in turfgrass sand-based root zones are not well understood. This study was conducted to characterize nutrient and chemical properties in putting greens influenced by root zone mixture and establishment treatment, putting green age, and soil depth. Putting greens were constructed and established with Agrostis stolonifera L. in sequential years from 1997 to 2000. Treatments included root zone mixtures of 80:20 (v:v) sand and sphagnum peat and 80:15:5 (v:v:v) sand, sphagnum peat, and soil, and accelerated versus controlled establishment. In the establishment year, the accelerated treatment received 2.6-, 3.0-, and 2.6-fold more nitrogen, phosphorus, and potassium, respectively, than the controlled treatment. Soil samples were taken in Fall 2001, Spring 2004, and Summer 2004 and were analyzed for nutrient and chemical properties such as pH, cation exchange capacity (CEC), organic matter (OM), total soluble salts (TSS), and 12 nutrients. The root zone mixture and establishment treatments had minimal effects on most nutrient and chemical properties with the exception of phosphorus and pH. Cation exchange capacity, OM, TSS, and all nutrients decreased with soil depth, whereas soil pH increased. The putting green age × soil depth interaction was significant for many of the nutrient and chemical properties, but separating soil samples into mat and original root zone instead of predetermined soil sampling depths eliminated most of these interactions. The mat layer had higher CEC and OM values and nutrient concentrations and lower pH values than the original root zone mixture.

A 35 kyr record of organic matter composition and δ13C of n-alkanes in bog sediments close to Lake Baikal: Implications for paleoenvironmental studies

We characterized the compositions of organic compounds in a Cheremushka bog sediment core (deposited over the last 35kyr), located at the eastern coast of Lake Baikal, to obtain basic information about the terrestrial organic matter (OM) which contributed to Lake Baikal sediments. The bog sediment was analyzed for the molecular composition of n-alkanes, lignin phenols and n-C24 to C30 alkanoic acids, as well as the carbon isotopic composition of plant wax derived n-C27 to C33 alkanes.Concentrations of lignin phenols [vanillyl (V) plus syringyl (S) phenols] normalized to total organic carbon (TOC) in the Holocene are twice those for the last glacial maximum (LGM), while concentrations of TOC-normalized n-C24 to C30 alkanoic acids do not change markedly in this period. Thus, the ratio of lignin phenols to n-C24 to C30 alkanoic acids increases from the LGM to the Holocene. This result is essentially consistent with pollen analysis indicating an expansion of woody plants in the Holocene and a prevailing herb-abundant environment for the LGM. The δ13C values of n-C27 to C33 alkanes (e.g. −29‰ to −33‰ for C31) indicate the presence of C3-dominant plants throughout the core.The contribution of terrestrial OM to Lake Baikal sediments was estimated using the biomarkers, on the assumption that the OM in the bog sediments is a representative of the terrestrial OM around the lake. Hence, the estimation using lignin phenol or n-C24 to C30 alkanoic acid parameters indicates that 11–24% of the TOC in the Academician Ridge sediments is land-derived for both the Holocene and the LGM, which is similar to the estimates from C/N values of bulk OM. However, the estimates for terrestrial OM using the n-C27 to C33 alkane parameter are generally higher than those using lignin phenol or n-C24 to C30 alkanoic acid parameters. The difference is thought to be associated with the difference in source and behavior of these biomarkers.

Landward changes of soil enzyme activities in a tidal flat wetland of the Yangtze River Estuary and correlations with physico-chemical factors

The landward changes of soil enzyme activities and physico-chemical properties of the surface sediment in Chongming Dongtan of the Yangtze River Estuary, were studied. Along the elevation gradient or succession series, the contents of total phosphorus ( TP), total nitrogen ( TN) and organic matter ( OM) in the sediment increased, but the average grain size ( AGS) of the sediment and the content of the dissolved inorganic phosphorus ( DIP) decreased. The activity of alkaline phosphatase increased gradually along the elevation gradient, and was positively correlated with the values of TP, TN and OM ( P<0.05), but negatively to AGS and DIP ( P<0.05). It was correlated with a mechanism of substrate inductivity and product inhibition. Catalase activity had the similar trend of gradual increase along the elevation gradient, enhancing the fertility of the soil and the oxidative process of OM in the sediment. Along the succession series, from the tidal flat to the bulrush ( Scirpus mariqueter) zone, and then to the reed ( Phragmites australis) zone, the activity of sucrase only changed insignificantly, but there was a higher activity in the bulrush zone than in other zones. The activity of proteinase decreased from the tidal flat to the reed zone, and the activity was negatively correlated with OM and TN ( P<0.05), but positively with DIP ( P<0.05). Through the succession zones a decrease in the number of diatoms resulted in a decline in the concentration of protein, which influenced the proteinase activity, suggesting that the proteinase in the sediment was produced by diatoms.

Tratabilidade da água do reservatório do Guarapiranga: efeitos da ozonização sobre algumas variáveis de qualidade das águas

Ensaios de tratabilidade em bancada tendo cloreto férrico como coagulante foram conduzidos para avaliar efeitos da pré-ozonização e da inter-ozonização sobre variáveis de qualidade de águas em diversas etapas de tratamento: demanda de cloro livre (DCL), absorbância de luz ultravioleta em 254 nm (abs UV254) e concentração de matéria orgânica (MO). Para águas decantadas, a ozonização favoreceu a remoção de MO, mas não pareceu influenciar a redução da DCL, em relação aos ensaios sem ozonização. Para as águas filtradas, os ensaios com ozônio proporcionaram maiores remoções de MO e valores da relação DCL/MO do que os ensaios sem ozônio, porém estes últimos foram mais eficientes na redução da DCL. A ozonização da água bruta reduziu a concentração de MO e a abs UV254 mas não a DCL. A DCL imediata da água bruta foi estimada e pareceu não depender do tempo de contato.

Effect of Soil Organic Matter Content and pH on Toxicity of Cadmium to Paronychiurus kimi (Lee) (Collembola)

The heterogeneous physico-chemical properties of soil make it difficult to normalize the toxicological effects of metals in the Collembolan species Paronychiurus kimi (Lee). Furthermore, the physico-chemical properties of soil themselves can function as limiting factors that affect population fitness. In this study, the effects of soil organic matter (OM) and pH on the biological performance of P. kimi were assessed, and the influence of these properties on cadmium toxicity to P. kimi was also assessed at the individual and population levels. The OM and pH were found to significantly influence offspring production. All toxicological values of cadmium to P. kimi showed consistent patterns of increase with increasing OM and pH values, implying a decreased toxicity. The 28-d LC 50 values varied from 34.9 to 115.9 mg/kg, and the 28-d EC 50 and 28-d r i =0 also varied depending on the OM and pH values. These findings indicate that the OM and pH values themselves are important factors in determining not only the biological performance of P. kimi but also the toxicity of cadmium to P. kimi on the individual and population levels. Therefore, when ecological risk assessments are conducted for a certain soil, pre-examinations of the effects of abiotic factors and the selection of an appropriate endpoint must be accomplished before establishing levels of chemicals of concern (COC) for a certain species.