Organic C

This paper seeks to summarize the present state of organization theory. It takes as its starting-point the work of early organization theorists and demonstrates that their work has been challenged in basically four different ways, i.e. regarding the view on (a) individuals in organizations, (b) the interaction among individuals in organizations, (c) the relationship between organizations and their environments and (d) the technology of organizations. The implications of these qualifications are discussed with reference to recent literature. These discussions led to the conclusion that the number of research questions have increased rather than decreased over the years. Thus, a unified organizatinn theory may be less valid today than at the beginning of the century. This circumstance, however, it is argued, should not he considered a regression but rather a sign of increasing insilzht.

Farmers are increasingly using zero tillage in Central Argentina to replace other tillage systems. Intensive tillage decreases soil organic matter content and causes physical degradation. The objective of this work was to evaluate changes in some soil biological properties induced by different tillage systems. A 6 year experiment in which continuous maize (Zea mays L.) was grown using three tillage systems (conventional tillage, reduced tillage and zero tillage) was carried out at C6rdoba Province, Argentina, on a Typic Argiudoll. Variations in total organic C content, microbial biomass C, metabolic quotient (qC0,) and the proportion of the organic C present in the microbial biomass were evaluated at two sampling depths (O-5 and 5-15 cm). Additional samples from a nearby site (undisturbed grassland) were also taken and considered as a control. Concentrations of soil organic C and microbial biomass C were higher under zero tillage as compared with conventional tillage, at the O-5 cm soil depth. Differences were not evident among tillage systems at the 5-15 cm soil depth. An analysis of the microbial biomass C content, in relation to the organic C, revealed higher values at the O-5 cm soil depth only for those systems which provoke less disturbance of the soil (i.e. reduced tillage and zero tillage). Significantly greater amounts of CO,-C were released from zero tillage and reduced tillage soils than from conventionally tilled soils. This release was positively correlated with microbial biomass C. qC0, values were not significantly different between tillage systems. Zero tillage proved to be more

N-mineralization and nitrification rates were studied, during May 1996 to June 1997, at six sites in Vindhyan region (four forest and two savanna sites) differing in terms of dominant vegetation, nutrient status, topography and soil moisture regime. During an annual cycle the maximum N-mineralization and nitrification rates were recorded in rainy season and minimum in summer season in all study sites. The annual N-mineralization and nitrification rates were highest at Hathinala forest moist site having maximum moisture content, organic-C, N and water holding capacity of soil than other study sites. N-mineralization and nitrification rates differ significantly across the sites and seasons. These rates were significantly correlated with soil moisture and mineral-N contents. The result suggested that variations in rates of N-mineralization and nitrification in the studied dry tropical ecosystems are related to differences in soil moisture content, nutrient status and vegetational cover in combination with other environmental factors. Resumen: Las tasas de mineralización de N y de nitrificación fueron estudiadas de mayo de 1996 a junio de 1997, en seis sitios de la región Vindhyan (cuatro sitios de bosque y dos de sabana) que difieren en términos de la vegetación dominante, el estatus de los nutrientes, la topografía y el régimen de humedad del suelo. Durante un ciclo anual las tasas máximas de mineralización del N y de nitrificación fueron registradas durante la estación lluviosa, y las mínimas en el verano, en todos los sitios de estudio. Las tasas anuales de mineralización de N y de nitrificación tuvieron sus picos en el sitio húmedo del bosque Hathinala, el cual tiene mayores contenidos de humedad, C orgánico, N y capacidad de retención de agua en el suelo que los otros sitios de estudio. Las tasas de mineralización del N y de nitrificación fueron significativamente diferentes entre sitios y estaciones. Estas tasas estuvieron correlacionadas significativamente con los contenidos de humedad en el suelo y de N mineral. El resultado sugiere que las variaciones en las tasas de mineralización de N y de nitrificación en los sistemas tropicales secos estudiados están relacionadas con las diferencias en el contenido de humedad en el suelo, el estatus de los nutrientes y la cobertura vegetal, en combinación con otros factores del ambiente.

An Inceptisol A-horizon from Hawaii was subjected to a series of reduction-oxidation cycles-14 d cycle length over a 56 d duration-across the ''soil-Fe'' [Fe(OH) 3 .Fe 2+ (aq) , log K o = 15.74] equilibrium in triplicate redox-stat reactors. Each reducing event simulated the flush of organic C and diminished O 2 that accompanies a rainfall-induced leaching of bioavailable reductants from the forest floor into mineral soil. The soil contained considerable amounts of short-range ordered (SRO) minerals (e.g., nano-goethite and allophane) and organic matter (11% org-C). Room temperature and cryogenic 57 Fe Mo ¨ssbauer spectroscopy showed that the iron-bearing minerals were dominated by nano-to micro-scale goethite, and that ferrihydrite was not present. Over the four full cycles, fluctuations in E h (from 200 to 700 mV) and pFe 2+ (from 2.5 to 5.5) were inversely correlated with those of pH (5.5 to 4). Here, we focus on the solubility dynamics of the framework elements (Si, Fe, Ti, and Al) that constitute 35% of the oxygen-free soil dry mass. Intra-cycle oscillations in dissolved (<3 kDa) metals peaked during the reduction half-cycles. Similar intra-cycle oscillations were observed in the HCl and acid ammonium oxalate (AAO) extractable pools. The cumulative response of soil solids during multiple redox oscillations included: (1) a decrease in most HCl and AAO extractable metals and (2) a transformation of SRO Fe (as nano-goethite) to micro-crystalline goethite and micro-crystalline hematite. This may be the first direct demonstration that Fe oxide crystallinity increases during redox oscillationsan a priori unexpected result.

Soil organic matter (SOM) has a key role in maintaining soil fertility in weathered soils in the tropics. This study was conducted to determine the contribution of different SOM fractions to the cation exchange capacity (CEC) of a tropical soil as influenced by organic matter inputs of different biochemical composition. Soil samples were collected from a 16-yr old arboretum established

Microbial community composition may be an important determinant of soil organic matter (SOM) decomposition rates and nutrient turnover and availability in agricultural soils. Soil samples were collected from six long-term tillage comparison experiments located along two climatic gradients to examine the eects of no-tillage (NT) and conventional tillage (CT) management on bacterial and fungal abundance and biomass and to examine potential controls on the relative abundances of bacteria and fungi in these two systems. Samples were divided into 0±5 and 5±20 cm depth increments and analyzed for bacterial and fungal abundance and biomass, total C and N, particulate organic matter C and N (POM-C and N), soil water content, texture, pH, and water-stable aggregate distributions. Soil moisture, which varied by tillage treatment and geographically with climate, ranged from 0.05 to 0.35 g g À1 dry soil in the surface 0±5 cm and 0.15 to 0.28 g g À1 dry soil at 5±20 cm. Measured organic matter C and N fractions and mean weight diameter (MWD) of water-stable aggregates were signi®cantly higher in NT relative to CT at three of the six sites. Fungal hyphal length ranged from 19 to 292 m g À1 soil and was 1.9 to 2.5 times higher in NT compared to CT surface soil across all sites. Few signi®cant tillage treatment dierences in soil physical and chemical properties or in fungal abundance and biomass were observed at 5±20 cm. Bacterial abundance and biomass were not consistently in¯uenced by tillage treatment or site location at either depth. The proportion of the total biomass composed of fungi ranged from 10 to 60% and was signi®cantly higher in NT compared to CT surface soil at ®ve of six sites. Proportional fungal biomass was not strongly related to soil texture, pH, aggregation, or organic C and N fractions, but was positively related to soil moisture (r = 0.67; P < 0.001). The relationship between soil moisture and the degree of fungal dominance was due to the positive response of fungal biomass and the lack of response of bacterial biomass to increasing soil moisture across the range of measured soil water contents. Tillage treatment eects on fungal biomass and proportional fungal abundance were not signi®cant when the data were analyzed by analysis of covariance with soil moisture as the covariate. These results suggest that observed tillage treatment and climate gradient eects on fungi are related to dierences in soil moisture. Further research is needed, however, to determine how tillage-induced changes in the soil environment shape microbial community composition in agroecosystems.

Microbial community composition may be an important determinant of soil organic matter (SOM) decomposition rates and nutrient turnover and availability in agricultural soils. Soil samples were collected from six long-term tillage comparison experiments located along two climatic gradients to examine the eects of no-tillage (NT) and conventional tillage (CT) management on bacterial and fungal abundance and biomass and to examine potential controls on the relative abundances of bacteria and fungi in these two systems. Samples were divided into 0±5 and 5±20 cm depth increments and analyzed for bacterial and fungal abundance and biomass, total C and N, particulate organic matter C and N (POM-C and N), soil water content, texture, pH, and water-stable aggregate distributions. Soil moisture, which varied by tillage treatment and geographically with climate, ranged from 0.05 to 0.35 g g À1 dry soil in the surface 0±5 cm and 0.15 to 0.28 g g À1 dry soil at 5±20 cm. Measured organic matter C and N fractions and mean weight diameter (MWD) of water-stable aggregates were signi®cantly higher in NT relative to CT at three of the six sites. Fungal hyphal length ranged from 19 to 292 m g À1 soil and was 1.9 to 2.5 times higher in NT compared to CT surface soil across all sites. Few signi®cant tillage treatment dierences in soil physical and chemical properties or in fungal abundance and biomass were observed at 5±20 cm. Bacterial abundance and biomass were not consistently in¯uenced by tillage treatment or site location at either depth. The proportion of the total biomass composed of fungi ranged from 10 to 60% and was signi®cantly higher in NT compared to CT surface soil at ®ve of six sites. Proportional fungal biomass was not strongly related to soil texture, pH, aggregation, or organic C and N fractions, but was positively related to soil moisture (r = 0.67; P < 0.001). The relationship between soil moisture and the degree of fungal dominance was due to the positive response of fungal biomass and the lack of response of bacterial biomass to increasing soil moisture across the range of measured soil water contents. Tillage treatment eects on fungal biomass and proportional fungal abundance were not signi®cant when the data were analyzed by analysis of covariance with soil moisture as the covariate. These results suggest that observed tillage treatment and climate gradient eects on fungi are related to dierences in soil moisture. Further research is needed, however, to determine how tillage-induced changes in the soil environment shape microbial community composition in agroecosystems.

Agriculture currently contributes significantly to the increase of CO2 in the atmosphere, primarily through the conversion of native ecosystems to agricultural uses in the tropics. Yet there are major opportunities for mitigation of CO2 and other greenhouse gas emissions through changes in the use and management of agricultural lands. Agricultural mitigation options can be broadly divided into two categories: (I)

Irrigation of agricultural land with wastewater will increase crop production, but also heavy metal concentrations and the rate of infection of farmers with pathogens. The risks associated with the use of wastewater are reduced by treating the wastewater, but treatment also reduces organic material, phosphorus and inorganic N for crops. We investigated characteristics, e.g. heavy metal concentrations, of soils of the valley of the Mezquital (Mexico)

The distribution of fertilizer phosphorus (P) in the soil profile affects its plant availability and the risk of P loss. We examined the P distribution and sorption in soil profiles of a field experiment initiated in 1942 on coarse sandy soil with four rates of lime (0, 4, 8 or 12 t ha -1 every 5-9 years) and two rates of P (no P or 15.6 kg P ha -1 annually). In 2016, intact soil cores were retrieved to 100 cm depth and divided into five depth intervals (0-20, 20-30, 30-50, 50-70 and 70-100 cm). Soil samples were analyzed for total P, P extracted with sodium bicarbonate (Olsen P) and water (P w ), oxalate-extractable P (P ox ), iron (Fe ox ) and aluminum (Al ox ), pH, carbon (C), and single point sorption index (PSI). Liming raised soil pH significantly at all depths. Addition of P increased total P, Olsen P, P w and P ox in the upper 30 cm only. In the topsoil the extractability of P in bicarbonate (Olsen P to total P ratio) and water (Pw to total P ratio) declined with liming. Below 30 cm, soil P pools were unaffected by lime and P application. PSI increased with depth until 50-70 cm and related strongly to content of Al ox , but not to Fe ox , Olsen P, soil C and pH. We conclude that Al ox plays a dominating role for retention of P in this sandy soil profile, formed by melt-water during the Weichsel glaciation period. The retention of P in soil below 30 cm depth was strong and unaffected by addition of lime.

The present publication is a compilation of the abstracts for the NJF seminar 438: Sensors for soil and plant mapping and terrain analysis, in Skara, Sweden, 27-28 October 2010. The objective of the seminar is to present a variety of measurement techniques and their applications to provide an opportunity for knowledge exchange and discussion concerning the use of sensors for soil and plant mapping, terrain analysis and other related subject areas.

Pimple mounds are circular to elliptical domes with basal diameters ranging from 3 to more than 30 m, and heights of 30 cm to more than 2 m above intermound levels. For almost two centuries, the origin of these features has been speculated upon by scientists without general consensus as to one of over 30 different mechanisms suggested for their origin. These soil microfeatures can be observed throughout portions of East Texas as well as Louisiana, Arkansas, Oklahoma, and Missouri. Pimple mounds have been extensively mapped throughout East Texas as complexes covering over 1.0 million ha in 47 soil survey areas. About 600,000 ha are on Pleistocene-age geological formations. This study focused on 5,500 ha in Leon County, Texas, mapped as Rader-Derly complex and Derly-Rader complex. Rader (Aquic Paleustalfs) is on mounds and Derly (Typic Glossaqualfs) in the low intermounds. These soils are mapped primarily on terraces of the Trinity River system within the survey area. Using elevation levels published for the various fluviatile terrace deposits of the Trinity River, six groups (five terrace level groups and an upland group) were identified for analysis of mounds within

The methods and procedures to be employed in meeting the objectives of this study have been extensively used in the field and in various soil laboratories. The project area was located in the southwest portion of Payne County, Oklahoma. It was bounded by the Cimarron River to the south, State highway 177 to the east, the RlW line to the west, and to the north by a line running east-west about six miles north of Perkins (Figure ).

Difficulties inherent in working with anaerobic microorganisms and mixed cultures have hampered efforts to detect and identify metabolites of anaerobic degradation of monoaromatic compounds. Isotope-trapping experiments and analysis using a high-performance liquid chromatograph equipped with a flow-through radioactivity detector were used to detect very low concentrations of metabolites. Data obtained by this method suggest that toluene was degraded via methyl hydroxylation by a mixed methanogenic culture.

Traditional models of software development like waterfall model fails to cope up with the rapid changes in business, process and technology. Hence many software organizations are now moving from traditional process models to Agile methodologies for their projects. There are many frameworks under agile umbrella, popular frameworks being Scrum, eXtreme Programming, Crystal and Kanban. Scrum is the most popular framework followed in Indian companies. Many times organizations find it difficult to identify a suitable tool for managing their agile projects and many of them uses excel based templates.

A long-term experiment (LTE) on a rice-wheat system was initiated in 1963 at the Kyushu National Agricultural Experiment Station, in Fukuoka, Japan, to determine the effects of continuous application of rye grasshheat straw, rice straw and rice straw compost, alone or in combination with inorganic N on crop yields. Increase in rice yields and enhancement of total soil C and N contents with the application of organic residues in this LTE have been reported earlier. However, evaluation of the changes in the soil microbiological properties and the decomposable C fraction of soil organic matter that is needed for soil quality assessment is still lacking. Soil samples were collected after rice harvest in 2003 from the organic residue treatments and unfertilized control, airdried and incubated for 1 month

In NW Patagonia, Argentina, poor regeneration after fires of Nothofagus pumilio (Poepp. and Endl.) Krasser forests located in drier environments has been attributed to probable edaphic changes. We studied the long-term effects of wildfire on the mineralogical, physical, chemical and biological properties of a soil developed from volcanic-ashes under N. pumilio forests. Soils from six small patches burned in January 1996 and of undisturbed forest were sampled at a depth of 0-10 cm in March 1996March , 1997March , 1998March and 2000. . As biological soil indicators we assessed N in microbial biomass (N-MB) and potential N mineralization (pNmin). Chemical properties were analyzed for all 4 years in dry samples, N-BM and pNmin in rewetted samples in 1996 and 1997, and in field-moist samples in 1998 (pNmin) and 2000 (N-MB). Additionally, we measured soil moisture twice during the growing seasons of 1998 and 2000 at 0-16 cm, and mineralogical and physical properties once in 1998. The main effects of fire were: (i) a significant increase in pH, electrical conductivity, extractable P and cations (Ca, Mg, Na, K) and a significant decrease in organic C and total N; 4 years after the fire, C and N were still, respectively, 52 and 20% lower, pH was one unit higher, and electrical conductivity and extractable P were twice as high as in the unburned control; (ii) a considerable decrease in N-MB (>90%), without significant recovery in subsequent years; (iii) an increase of pNmin at the beginning of the incubation period, decreasing afterwards to only 4-44% the levels in the unburned soil; and (iv) a decrease of 31% in field capacity and 56% in soil moisture. No mineralogical changes in the amorphous soil components were observed. Although volcanic soils show a high capacity to stabilize organic matter, buffer pH, retain P and store water, the magnitude of the changes of all soil properties indicated that the intensity of the fire was very high, and might have a powerful effect on seedling emergence and survival.

This study investigated microbial biomass-N (MB-N) and N-mineralization in soils of four different vegetation systems including forest (sal), mixed forest, savanna and cropland ecosystems in the Vindhyan region, India. A change was noted in the above region due to physiographic differences and anthropogenic disturbances. Annually the soil moisture (SM) content across the different study sites ranged from 7.5 to 24.3% being maximum in forest sites compared to savanna and cropland sites. The NH 4 + -N, NO 3 --N and MB-N concentrations varied from 4.3 to 10.2 µg/g, 1.1 to 5.8 µg/g and 21.3 to 90.2 µg/g dry soil, respectively, with minimum values in the wet and maximum values in the dry season. The trend of seasonal variation in net N-mineralization was similar to that of moisture content but counter to the concentrations of inorganic-N and MB-N. The net N-mineralization rates at different investigated sites ranged from 4.5 to 37.6 µg/g month. Cultivation reduced the N-mineralization and MB-N by 58.5% and 63.5%, respectively. Experiments showed that the percentage contribution of MB-N to total-N was 8.01 to 19.15%. MB-N was positively correlated with the inorganic-N (n = 180, r = 0.80, p < 0.001) but negatively with soil moisture (n = 180, r = 0.79, p < 0.001) and net N-mineralization rates (n = 180, r = 0.92, p < 0.0001). The higher N-mineralization and MB-N in the soil of forest ecosystem was reported compared to savanna and cropland and the order of soil MB-N levels and net N-mineralization followed the sequence: forest (sal) > mixed forest > savanna > cropland.

Land use changes such as transformation of natural landscapes, forest degradation and increase in croplands due to human activities are considered amongst the most influential ecological disturbances affecting soil, ecosystems and environmental sustainability. The previous works from India are limited to show that soil disturbances influence abiotic and biotic factors along a rural-urban gradient. However, variations in soil microbial biomass (SMB) -C, -N and -P quantity due to land use changes at different soil depths across different land use types remain poorly understood on comparative ground. We investigated the impact of land use types on soil properties and SMB -C, -N and -P levels across different soil depths (0-10, 10-20 and 20-30 cm) in dry tropical uplands. Four land use types/covers (natural forest, mixed forest, savanna and agriculture land) were selected. The present study is based on two hypotheses: i) different land use types affect SMB levels in top surface soil (0-10 cm), but have less effects in deeper soil profiles (20-30 cm); and ii) SMB levels in top surface soil are highest in natural forest, followed by mixed forest and then savanna and agriculture lands. ANOVA showed significant differences in SMB values due to land use covers (P < 0.001), soil depths (P < 0.001) and land use types × soil depths interaction (P < 0.001). Although, there had no effect of land use types on SMB levels in deeper soil profiles (20-30 cm) but soil parameters (soil pH, soil moisture, soil temperature, total-N, C/N ratio and organic-C) significantly affect SMB levels in top surface (0-10 cm) soil. The study suggests that SMB may be considered as a key indicator of soil fertility index, while land use practices are a major cause for loss of microbial community composition/biomass in dry tropical upland soil.

A field study was conducted at a dry-land agricultural farm during paddy crop season to assess the effect of fly ash (FA) and farmyard manure (FYM) amendments on the dynamics of inorganic-N (NH 4 + and NO 3 -), N-mineralization and nitrification rates and paddy yields. Four treatments, each consisted of three replicates, were established in completely randomized block design. The treatments were: control, 50 t ha -1 FA, 50 t ha -1 FYM, and FA + FYM (each 50 t ha -1 ). The variations in soil physico-chemical properties due to treatments were statistically significant. Across different treatments, FA + FYM treated plot had significantly higher organic-C, total-N, total-P, water-holding capacity, but lower bulk density compared to control plot. The effect of various amendments and months was significant for soil inorganic-N (NH 4 + and NO 3 -) concentrations, soil moisture (SM) content, N-mineralization and nitrification rates. Across various amendments and sampling months, inorganic-N, SM, N-mineralization and nitrification rates were greatest in FA + FYM treated plot in August month. An exponential positive relationship existed between gravimetric SM content and N-mineralization (R 2 = 0.865) and nitrification (R 2 = 0.633) rates. The SM content was negatively correlated with NH 4 + (R 2 = 0.841) and NO 3 -(R 2 = 0.920). The various selected paddy agronomic parameters and yields differed significantly due to treatments. The most effective treatment noted for paddy grain yield was the combination of FA + FYM (92% increase over control) followed by FYM and FA. Significant correlation was noted among soil physico-chemical properties (except soil pH) and paddy productivity. The results suggested that FA and FYM amendments enhance the rates of Ntransformation processes, plant available-N and paddy productivity. Thus, FA and FYM can be used as potential amendments to enrich soil productivity and crop yields for dry tropical nutrient poor soils.

Intensive agricultural practices can determine a decline in soil fertility which represents the main constraint to agricultural productivity. In particular, the progressive reduction in soil organic matter, without an adequate restoration, may threaten soil fertility and agriculture sustainability. Some soil management practices can improve soil quality by adding organic amendments as alternative to the sole use of mineral fertilizers for

The present study investigates the impact of fire (low and high severity) on soil fungal abundance and microbial efficiency in C assimilation and mineralisation in a Mediterranean maquis area of Southern Italy over 2 years after fire. In burned and control soils total and active fungal mycelium, microbial biomass C, percentage of microbial biomass C present as fungal C, metabolic quotient (qCO 2) and coefficient of endogenous mineralisation (CEM) were assayed together with several chemical properties of soil (i.e. pH and contents of organic C, total and mineral N, available K, Mg, Mn and water). Fire significantly decreased the fungal mycelium, whereas it stimulated microbial growth probably through the enhancement of bacterial growth because of the increase in organic C and nutrient contents in burned plots. This shift in microbial community composition might explain the observed reduction in soil microbial efficiency of C assimilation (high qCO 2) and the increase in C mineralisation rate (CEM) in the first 84 days after fire. Therefore, fire might increase CO 2 input to the atmosphere not only during combustion phase but also in the post-fire period.

We examined the medium-term (3 year) effects of no-tillage, reduced tillage (subsoil-bedding and shred-bedding) and water regime on the soil profile distribution of organic matter and physical and microbiological soil quality indicators in a maize field under subtropical conditions. Soil carbon sequestration was evaluated as well. Residue on the soil surface was about 17-21-fold increased in the no-tillage plots over the mouldboard plough plots, with intermediate increases in the reduced tillage plots. In the surface 0-5 cm, organic matter decreased with increasing tillage and was increased by irrigation. The no-tilled soil had increased values of water-soluble C, dehydrogenase, urease and acid phosphatase activities, aggregate stability and glomalin compared to tilled soils, especially in the shallowest (0-5 cm) layer. The water regime had no effect on soil structural stability or total microbial activity.

The objective of the paper is to present information concerning sources if heavy metals to waste, harmful effects of heavy metals, the problems posed by the disposal and recycling of heavy metals and heavy metal containing products, and to assess the options for substituting the heavy metals. In recent years, some heavy metals such as cadmium, lead, zinc, nickel, copper and chromium (III) or their compounds have been used extensively by various industries thus leading to sharp increase in the contamination especially of water. Because of their toxicity, the presence of any of these metals in excessive quantities will interfere with many beneficial uses of the water. As a result, the standard B discharge limit of these metals under Environmental Quality Act 1974 of Malaysia, (Sewage and Industrial Effluents) 1979 are kept below 1.0 mg/l in which the standard for Cd is 0.02 mg/l, 0.50 mg/l for Pb, 1.0 mg/l each for Zn, Ni, Cu and Cr (III). Despite of their potential toxicity, many of these metals are widely used, particularly by industries, which rely on solutions of the metallic ions. This paper reviews heavy metals pollution in Malaysia and potential removal techniques, which may be suitable to overcome the problem.

Concentrations of major nutrients (C, N, P) and acid soluble metals (Ca, Mg, K, Al, Fe, Mn, Pb, and Zn) were determined in modern (0–1 cm) and pre-acidification (5–10 cm) sediment layers collected from 37 alpine and 3 forest lakes in the Tatra Mountains (Slovakia, Poland) in 1996–1998. Sediment composition reflected catchment characteristics and productivity of lakes. In the sediments of alpine lakes, C and N concentrations decreased and Mg increased with a decreasing proportion of vegetation and soil in the catchment. Decreasing Ca:Mg ratios in sediments along the vegetation gradient was inverse to that in water, and could be associated with different ratios of cations in water leachate from catchments and in solids which enter the lake due to soil erosion. Phosphorus concentrations increased with the proportion of moraine areas, with till soils rich in P. Concentrations of C, N, P, and Ca in sediments positively correlated to their concentrations in water. Sediment concentrations ...

ABSTRACTCertain organic C moieties of soil origin in drinking source waters of Sacramento–San Joaquin Delta (Delta) can react with chlorine to form trihalomethanes (THMs) during the disinfection process. Isolation and characterization of them and quantitation of their THM formation potential (THMFP) is necessary for developing effective strategies to reduce their influxes in Delta waters and for removing them during drinking water treatment. In this study, organic C from two Delta soils was extracted using deionized H2O and four Na‐ or Ca‐based electrolytes of varying electrical conductivity values. Extracts were filtered into particulate, colloidal, fine colloidal, and soluble organic C for quantitation and THMFP determination. Results suggested that &lt;1.5% of soil organic C was electrolyte‐extractable. The soluble organic C fraction from both soils dominated in quantity and THMFP. Electrolyte effects were cation dependent. Sodium‐based electrolytes at either conductivity level d...

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Land use has the possibility of changing how much carbon is accumulated in the soil. The carbon balance of terrestrial ecosystems is impacted by rapid urban and agricultural expansion, which highlights the necessity of stepping up environmental protection. This research work was carried out at the Department of Crop, Soil and Pest Management, FUTA, to access the effect of concretionary nodules on nutrient composition, carbon forms and variation of soil carbon as affected by landuse and soil depth in Owu-Isin, Southern Guinea Savannah of Nigeria. Collection of samples for the study was from three forest lands and three intensively cultivated farmlands (both with visible presence of concretion nodules) at depths of 0-15 cm, 15-30 cm and 30-45 cm each. Physical properties of the soil under the influence of concretions as affected by the land use and depths, effect of landuse and depth on selected chemical properties of soil and interactive effects of different carbon forms on soil (SOL), concretion (CON) and soil + concretion (SCN) was recorded. The result shows that the sand particles in intensively cultivated land was not significantly different (p>0.05) from that of forest. Forest landuse recorded higher silt (8.44%) than intensively cultivated land use (8.01%) but the difference was not significant (P>0.05). The highest clay fraction was obtained in forest land use (19.47%) but it was not significantly (P>0.05) different from 18.78 % recorded in intensive land-use. The influence of depth on sand, silt and clay particles was not significant different (P>0.05). The interactive effect of both landuse and depth was not significantly different (P>0.05). There were significant differences in soil nutrient status amongst the landuse and soil depth. Soil (SOL) pH and Mg are significantly (P<0.05) higher in forest landuse than in intensive landuse with no significant difference in Mg. In contrast, soil P, exchangeable bases (K, Na & Ca) and exchangeable acidity (H + & Al 3+) are significantly (P<0.05) higher in intensively cultivated land than forest landuse with no significant differences. The result showed that intensively cultivated soil was significantly higher than forest soil in CEC. Furthermore, the result reflected that organic carbon (OC) and organic matter (OM) in this study were affected by land use and were significantly different (p<0.05). organic carbon (OC) and organic matter (OM) was affected by soil depth but not significantly different (p>0.05). The particulate organic matter (POC) in forest soil was the same with intensively cultivated soil and not significantly different from each other. However, the result shows that for the microbial biomass carbon (MBC), Forest soil was lower than intensively cultivated land use but not significantly different (p>0.05) from each other. These research works suggested that, if farmers can effectively optimised land use structure and management, biomass and soil carbon pools may be expanded, which will promote the capacity of terrestrial ecosystems to store carbon. Land use regulations that guarantee stable regions of various land-use categories, notably forested and arable land, would be advantageous for the carbon sequestration process.

Dissolved organic C (DOC) plays important roles in nutrient cycling and methane production in flooded rice ecosystem. The microcosm experiment was carried out to measure directly the contribution of photosynthates to DOC by using a 13 C pulse-chase labeling technique. DOC was operationally divided into water-extractable organic C (WEOC) and salt-extractable organic C (SEOC) by successive extraction firstly with deionized water and then with 0.25 M K 2 SO 4 . Total WEOC increased with plant growth, whereas SEOC concentration did not change significantly over the growing season. About 0.037-0.36% (mean 0.16%) of the assimilated 13 C was incorporated into WEOC immediately after 13 CO 2 assimilation (Day 0), but only 0-0.025% (mean 0.01%) was incorporated into SEOC. At the end of the growing season, the 13 C amounts of WEOC substantially decreased, while those of SEOC slightly increased. The estimated net plant C contribution was 21 mg C plant À1 to WEOC and 6 mg C plant À1 to SEOC, corresponding to 33.8% of total WEOC and 20.2% of total SEOC at the end of the growing season, respectively. The results suggest that the incorporation and decomposition of the photosynthesized C occurred rapidly in rice soil which significantly affected the WEOC dynamics, but SEOC appeared to be in equilibrium with the native soil organic matter, receiving less effect from the plant growth.

Mineralization of nitrogen (N) and sulfur (S) were examined over a 31-week incubation period under aerobic conditions in 13 soils selected from the mountainous district of Pertouli, central Greece. The main native plant species are turf, forage crops, forest trees, herbs, and shrubs. Net mineralization and immobilization of N and S by indigenous plants were estimated. Most soils are acidic in this xeric, mesic climatic regime, and organic carbon (C), organic nitrogen (N), and sulfur (S) appreciably varied in soils and plant species. The cumulative net mineralization of N is much higher in comparison to the amount of mineralized S. Release of N is curvilinear with time and associated with a declining mineralization in the later stages of the incubation. Close relationships exist between soil organic S and N and between organic C and N, indicating that these elements are mainly bound in the organic matter. The cumulative net mineralization from soils varies greatly and ranges between 36.6 and 212.8 (average 104.8) mg/kg for N and between 21.4 and 45.2 (average 31.8) mg/kg for S. Immobilization occurs in most soils amended with indigenous plant residues, with the amount of immobilized N varying between 14.8 and 49.5 mg/kg and that of immobilized S ranging from 2.6 to 30.7 mg/kg. However, the estimated rates of N and S mineralization are not negligible and can be taken into account as potential sources in the management of the upland soils.

This paper aims at understanding the effect that shrub encroachment into mesic mountain grasslands has on soil organic carbon (SOC) stocks. Thus we compared organic C and N contents in contiguous soil profiles under a conifer shrub, a legume shrub, and grasses (mesic grasslands) on 21 sites. Soil C and N recalcitrance indexes (RIC and RIN) were estimated as the ratio of unhydrolyzable C and N to total C or N. Contrary to our hypothesis, shrub encroachment did not cause a well‐defined change in soil C stocks. Only a slight increase in C was detected in the top 15 cm soil layer under both shrubs. The C accretion rate in this soil layer was estimated to be approximately 28–42 g m−2 per annum. Legume shrub encroachment also produced a slight decrease in the C/N ratio in the top 15 cm soil layer. No significant changes in the RIC were detected as a result of encroachment; however, slight decreases in the RIN were found at medium depths. Both RIC and RIN showed a negative relationship wit...

Field experiments were conducted at Owo, southwest Nigeria to select organic fertilizer treatments most suitable for sustaining high soil fertility and yam productivity on a nutrient-depleted tropical Alfisol. Eight organic fertilizer treatments were applied at 20 t ha 71 with a reference treatment inorganic fertilizer (NPK 15-15-15) at 400 kg ha 71 and natural soil fertility (control), laid out in a randomized complete block design with three replications. Results showed that organic fertilizers significantly increased (p ¼ 0.05) tuber weight and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and organic C concentrations compared with the NSF (control). The oil palm bunch ash þ poultry manure treatment increased tuber weight, vine length, number of leaves and leaf area of yam by 66, 25, 21 and 52%, respectively, compared with inorganic fertilizer (NPK) and 37, 22, 19 and 44%, respectively, compared with poultry manure alone. Sole or mixed forms of organic fertilizers showed significant improvement in soil physical conditions compared with IF (NPK) and NSF (control). Synergistic use of oil palm bunch ash þ poultry manure at 10 t ha 71 each was most effective for sustainable management of soils and for improving agronomic productivity of yam.

The discovery of natural 210 Po enrichment at levels exceeding 500 mBq/L in numerous domestic wells in northern Nevada, USA, led to a geochemical investigation of the processes responsible for its mobilization. 210 Po activities in 63 domestic and public-supply wells ranged from below 1 mBq/L to 6590 ± 590 mBq/L, among the highest reported levels in the USA. There is little spatial or depth variability in 210 Pb activity in study-area sediments and mobilization of a few percent of the 210 Po in the sediments would account for all of the 210 Po in water. Stable-isotope measurements indicate SO 4 reduction has occurred in all 210 Po contaminated wells. Sulfide species are not accumulating in the groundwater in much of Lahontan Valley, probably because of S cycling involving microbial SO 4 reduction, abiotic oxidation of H 2 S to S 0 by Mn(IV), followed by microbial disproportionation of S 0 to H 2 S and SO 4 . The high pH, Ca depletion, MnCO 3 saturation, and presence of S 0 in Lahontan Valley groundwater may be consequences of the anaerobic S cycling. Consistent with data from naturally-enriched wells in Florida, 210 Po activities begin to decrease when aqueous sulfide species begin to accumulate. This may be due to formation and precipitation of PoS, however, Eh-pH diagrams suggest PoS would not be stable in study-area groundwater. An alternative explanation for the study area is that H 2 S accumulation begins when anaerobic S cycling stops because Mn oxides are depleted and their reduction is no longer releasing 210 Po. Common features of 210 Po-enriched groundwater were identified by comparing the radiological and geochemical data from Nevada with data from naturally-enriched wells in Finland, and Florida and Maryland in the USA. Values of pH ranged from <5 in Florida wells to >9 in Nevada wells, indicating that pH is not critical in determining whether 210 Po is present. Where U is present in the sediments, the data suggest 210 Po levels may be elevated in aquifers with (1) SO 4 -reducing waters with low H 2 S concentrations, or (2) anoxic or oxic waters with extremely high Rn activities, particularly if the water is turbid.

2-Keto-4-methylthiobutyric acid (KMBA) has been identified as an intermediate in methionine-derived ethylene (C 2 H 4) biosynthesis by microbial cultures. This study was designed to assess the effectiveness of KMBA as an C 2 H 4 precursor in soil. Gas chromatographic analysis indicated that amendment with KMBA (up to 10 mM) stimulated the biosynthesis of C 2 H 4 in two Pakistani soils. Results also revealed that substrate-(KMBA)-dependent C 2 H 4 production was inhibited when the soils were amended either with glucose (as a C source), NH 4 NO 3 (N source) or antibiotics. The KMBAderived C 2 H 4 biosynthesis in both soils was maximum when the soil suspension was amended with 10 mM substrate and incubated at pH 7.5 for a period of 120 h at 35C with shaking. Comparison of soils revealed that C 2 H 4 production was relatively greater in a silty clay loam S 1 (containing 1.15% organic C) soil compared to a loamy S 2 (containing 0.54% organic C) soil. KMBA was found to be an equally effective substrate of C 2 H 4 when compared with another intermediate, 1-aminocyclopropane-1-carboxylic acid (ACC), whereas, a-ketglutaric acid failed to serve as an C 2 H 4 substrate in soil. As far as we know, this is the first study reporting KMBAdependent C 2 H 4 production in soil.

Soil-feeding termites transport soil for mound building, and this process can affect soil characteristics. To verify the influence of soil termite activity on soil characteristics, samples were collected from top, bottom and center of termite mounds, and of the adjacent area, to assess chemical and physical properties and mineralogical composition. Four replicates of termite mounds and respective adjacent areas were randomly sampled in Lages, Capão Alto, Painel, São José do Cerrito and Coxilha Rica (State of Santa Catarina, southern Brazil). Results of chemical analyses showed a greater content of K, P, Ca, Mg and organic C in the inner part of termite mounds, accompanied by lower pH in relation to soil of the adjacent area. There were no differences regarding clay mineral composition between termite mounds and adjacent soil, however the proportion of sand and clay differed between them. It is concluded that termites modify soil characteristics due to great volume of soil transporte...

This paper is a synthesis of the use of selected trace elements as proxies for reconstruction of paleoproductivity and paleoredox conditions. Many of the trace elements considered here show variations in oxidation state and solubility as a function of the redox status of the depositional environment. Redox-sensitive trace metals tend to be more soluble under oxidizing conditions and less soluble under reducing conditions, resulting in authigenic enrichments in oxygen-depleted sedimentary facies. This behavior makes U, V and Mo, and to a lesser extent certain other trace metals such as Cr and Co, useful as paleoredox proxies. Some redoxsensitive elements are delivered to the sediment mainly in association with organic matter (Ni, Cu, Zn, Cd) and they may be retained within the sediment in association with pyrite, after organic matter decay in reducing sediment. This particularity confers to Ni and Cu a good value as proxies for organic C sinking flux (frequently referred to as productivity). Elements with only one oxidation state such as Ba and P are classically used to assess paleoproductivity levels but they suffer from the fact that they are solubilized under reducing conditions and may be lost from oxygen-deprived sediments. The combined used of U, V and Mo enrichments may allow suboxic environments to be distinguished from anoxic-euxinic ones. Specifically, these elements tend to be much more strongly enriched in anoxic-euxinic environments and to exhibit weaker covariation with TOC than in suboxic environments.

Data collected over the summer-autumn dry season in Tomales Bay, California, demonstrate that system to be exporting dissolved P and importing dissolved fixed N. A simple explanation for the observed pattern is net system heterotrophy by about 8%, with < 2% of the system primary production of organic C being oxidized by denitrification. The loss of fixed N to denitrification consumes the dissolved inorganic N (DIN) liberated through the 8% excess organic oxidation over organic production. There is a small hydrographic loss of dissolved organic N (DON). The DIN deficit for primary production is therefore caused by the system C metabolism. Thus, C metabolism has profound effect on the N cycle, even though this denitrification rate is trivial to the C cycle. We believe that this pattern of C-controlled N cycling has wide general application. There exists considerable controversy about nitrogen vs. phosphorus as the nutrient exerting primary control on organic production in the sea. Redfield (1958) concluded that P regulates organic production of the global ocean over geological time. River flow is the only significant external source for P. River flow also delivers N, but flux from the atmosphere is potentially also important. Most organisms cannot use N2 who said most of this some time ago:

O objetivo deste trabalho foi examinar o carvao vegetal como condicionador de solo, avaliando especificamente sua influencia sobre a materia orgânica do solo, com enfase nas substâncias humicas (SH) (acidos fulvicos-AF, humicos-AH e humina-HUM). O experimento foi desenvolvido em campo (blocos ao acaso), em Plintossolo Haplico de textura argilo arenosa, localizado em Nova Xavantina-MT.

This article explores why iteration, rather than any specific methodology, is the true cornerstone of modern software development. It discusses the evolution of software practices from traditional linear models to more adaptive and iterative approaches, emphasizing that the essence of successful projects lies in understanding where iteration adds value. While Agile Methodology popularized iteration, it is iteration itself that drives adaptability, learning, and meaningful progress. This piece aims to demystify Agile practices and refocus attention on the real power of iteration across various contexts and methodologies.

SÉDIMENTOLOGIE RÉSUMÉ.-Le remplissage sédimentaire de trois lagunes du Golfe du Lion GÉOCHIMIE (Canet-S'-Nazaire, Salses-Leucate, Bages-Sigean) résulte de la transgression holocène LAGUNE qui a envahi des dépressions naturelles. Leur spécificité morphosédimentaire dépend GOLFE DU LION des structures et paléo-reliefs initiaux, mais également de l'importance des arrivées terrestres et marines qui contrôlent les vitesses de sédimentation et du fort impact des conditions météorologiques propres au climat méditerranéen. Bien que soumises aux mêmes phénomènes généraux, ces lagunes présentent chacune leurs particularités suivant leur degré de confinement et de colmatage, l'importance des apports terrestres et marins. Ces effets restent sensibles au niveau de la nature du remplissage holocène et des caractéristiques du fonctionnement actuel : hydrodynamisme, processus de sédimentation, comportement des éléments minéraux et des composés organiques. Ils influent également sur les caractères des divers gradients granulométriques et géochimiques existant sur toute l'étendue des plans d'eau et dans l'épaisseur des dépôts. SEDIMENTOLOGY ABSTRACT.-The sedimentary filling of the three lagoons of Golfe du Lion GEOCHEMISTRY (Canet-St-Nazaire, Salses-Laucate, Bages-Sigean) can be attributed to the holocène LAGOONS transgression which invaded natural dépressions. Their typical morphosedimentary GOLFE DU LION characters resuit from initial structures and paleoreliefs, the extent of terrestrial and marine supply which control the rates of sédimentation and strong effects of meteorological conditions characteristic of Mediterranean climate. Although subjected to the same gênerai phenomena, each lagoon reveals individual particularities according to the degree of confinement and filling and the extent of terrestrial and marine supply. The nature of the Holocène deposits and the actual working of minerai and organic components resuit from thèse effects. They also influence various granulometric and geochemical trends : vertically throughout the sédiment thickness and horizontally both in water and sédiment ail over the study area.

The responses of the continental slope benthos to organic detritus deposition were studied with a multiple tracer approach. Study sites were offshore of Cape Fear (I) and Cape Hatteras (III), NC (both 850 m water depth) and were characterized by different organic C deposition rates, macrofaunal densities (111>1 in both cases) and taxa. Natural abundances of 13Cand 12Cin particulate organic carbon (POC), dissolved inorganic carbon (DIC) and macrofma indicate that the reactive organic detritus is marine in origin. Natural abundance levels of 14Cand uptake of 13C-labeleddiatoms by benthic animals indicate that they incorporate a relatively young component of carbon into their biomass. '3C-labeled diatoms (Dalmsiosirapseudom~) tagged with 219b, slope sediment tagged with 113Snand 228Th-labeledglass beads were emplaced in plots on the seatloor at both locations and the plots were sampled after 30 min., 1-1.5 d and 14 mo. At Site I, tracer diatom was intercepted at the surface primarily by protozoans and surface-feeding annelids. Little of the diatom C penetrated below 2 cm even after 14 months. Oxidation of organic carbon appeared to be largely aerobic. At Site III, annelids were primarily responsible for the initial uptake of tracer. On the time scale of days, diatom C was transported to a depth of 12 cm and was found in animals collected between 5-10 cm. The hoeing of tracer fkom the surface by the maldanid Praxi/le2a sp. may have been responsible for some of the rapid nonlocrd transport. Oxidation of the diatom organic carbon was evident to at least 10 cm depth. Anaerobic breakdown of organic matter is more important at Site HI. Horizontal transport, which was probably biologically mediated, was an order of magnitude more rapid than vertical displacement over a year time scale. If the horizontal transport was associated with biochemical transformations of the organic matter it may represent an important but nearly invisible diagenetic process.

Understanding of crop residue mineralization is imperative for crop residue management in crop production. Carbon (C) and Nitrogen (N) mineralization dynamics of rice and wheat residues under surface applied and soil incorporated conditions were evaluated in the review paper. Both rice and wheat residues either incorporated or surface applied immobilized soil mineral N. Incorporated residues increased soil organic carbon and soil aggregate stability significantly by 18% and 55% over control, respectively. This review study indicated that crop residues incorporated into the soil have higher decomposition rate with a quicker mineral N release, more organic matter build up and soil structure improvement than retaining crop residues at the soil surface. Compost amendment also significantly lowered the specific activities of invertase in macro-aggregates and the silt + clay fraction, and this effect was more pronounced than the addition of fertilizer NPK. In contrast, inorganic fertilize...

Mixtures of organic and inorganic wastes were incubated to examine the changes in organic C (OC) contents. An anaerobic sludge and a CaO-treated aerobic sludge, with OC concentrations of 235 and 129 g kg À1 , were used. The inorganic wastes used-referred to as ''conditioners"-were shot blasting scrap, fettling, Linz-Donawitz slag, foundry sand (FS), and fly ash from wood bark combustion (FA). The total OC (TOC) and KMnO À 4 oxidized OC were determined. DTA-TGA profiles and FTIR spectra were also obtained. Mixtures made with the FS contained significantly lower (P < 0.05) amounts of TOC (45 g kg À1) than the rest of mixtures, which was attributed to the non-existence of reactive surfaces in the conditioner and the increased aeration induced by this material. Those made with FA contained significantly higher (P < 0.05) amounts of TOC (170 g kg À1), which was attributed to: (i) the addition of an extra source of C-black carbon (BC)-in the FA, and (ii) the inhibition of mineralization from the compounds present in this conditioner (e.g., amorphous aluminosilicates, BC). The results highlight the importance of the characteristics of the conditioners on the fate of the OM originating from the sludges.

Mixtures of organic and inorganic wastes were incubated to examine the changes in organic C (OC) contents. An anaerobic sludge and a CaO-treated aerobic sludge, with OC concentrations of 235 and 129 g kg À1 , were used. The inorganic wastes used-referred to as ''conditioners"-were shot blasting scrap, fettling, Linz-Donawitz slag, foundry sand (FS), and fly ash from wood bark combustion (FA). The total OC (TOC) and KMnO À 4 oxidized OC were determined. DTA-TGA profiles and FTIR spectra were also obtained. Mixtures made with the FS contained significantly lower (P < 0.05) amounts of TOC (45 g kg À1) than the rest of mixtures, which was attributed to the non-existence of reactive surfaces in the conditioner and the increased aeration induced by this material. Those made with FA contained significantly higher (P < 0.05) amounts of TOC (170 g kg À1), which was attributed to: (i) the addition of an extra source of C-black carbon (BC)-in the FA, and (ii) the inhibition of mineralization from the compounds present in this conditioner (e.g., amorphous aluminosilicates, BC). The results highlight the importance of the characteristics of the conditioners on the fate of the OM originating from the sludges.

Living biomass contains 45 to 60Vo carbon and 0.05 to 3Vo niftogen, in dry weight. Like throughout Europe, the mount of living biomass in Finnish forests has increased on average over the last decades, largely because of \-zhanges in forest management. The storage of organic C and N in biomass has also increased. Changes in biomass vary between regions. Data were analysed on changes in the last 30-40 years in C and N storage in living trees in Finland, subdivided into 20 regions. Tree biomass increased in 17 regions, and decreased in 3 rigions. The storage rate varied between-170 and + 480 kg C ha-I a-l, and between-0.5 and + I.2kg N ha-I Nitrogen accumulation in trees was less than l5%o of atmospheric N deposition in all regions. Although the eventual increase of the nitrogen concenfration in tree tissues was omitted, it is not possible that living biomass has been the major sink for atmospheric N deposition to forests. A hypothesis is presented that the main sink is litter layer and organic soil. Carbon can also be accumulating in soils essentially faster than hitherto estimated in analyses of carbon budgets of European forests.