Higher Nitrogen Values Research Articles

Relationship between mineral fertilization, plant macro- and microelement contents and yield of wheat (Triticum aestivum L.)

Abstract. The effectiveness of mineral fertilization on wheat productivity was determined in a field experiment on Alluvial-meadow soil (Fluvisol, FAO 2015) at the experimental field of Tsalapitsa village, Plovdiv region, during 2019-2020. Four increasing rates of nitrogen fertilization along with a constant background of phosphorus fertilization were tested in the following variants: N40P100; N80P100; N120P100; N160P100, and N0P0 (control) – without any fertilization. The influence of these variants on yield and the content of basic macro- and microelements in wheat’s dry biomass were assessed. Plant samples were collected at the full maturity phase of wheat, with each variant sampled in triplicate, to determine the concentrations of N, P, K, Ca, Mg, Cu, Zn, Mn, and Fe. Correlation analysis and analysis of variance (ANOVA) were employed to identify dependencies between observed variables. Significant differences between the variants for N% content in grain, chaff and straw of wheat were established. The highest nitrogen values were observed in the grain of the N160P100 and N120P100 variants, at 2.10% and 2.02%, respectively. The applied fertilization had a significant positive effect on the accumulation of potassium, calcium, copper, manganese and iron in wheat biomass. This finding was supported by the correlation coefficients between fertilizer rates and N (R = 0.948), Ca (R = 0.854), Cu (R = 0.681), Mn (R = 0.735), and Fe (R = 0.769) in the wheat grain. Significant yield differences were observed among the variants, with the highest yield recorded for N120P100 (7123.0 kg/ha), more than tripling that of the control variant. The uptake of nitrogen, phosphorus and potassium by the total biomass of wheat increased depending on the fertilization rates and it was the highest in the N120P100 variant.

Isotopic niche of New Jersey terrapins suggests intraspecific resource partitioning, and little variability following a major hurricane

Diamondback terrapins (Malaclemys terrapin) are sexually dimorphic generalist turtles that inhabit salt marshes and estuaries along the Atlantic and Gulf coasts of the United States. On October 29th, 2012, Hurricane Sandy made landfall in New Jersey, USA, directly impacting terrapin populations inhabiting central and southern Barnegat Bay. To examine potential food web mediated impacts to the terrapin population and their foraging dynamics we examined carbon and nitrogen stable isotope values collected from terrapin tissues (2011, 2015, 2019) and resource taxa (2015, 2019) within Barnegat Bay. Isotopic analysis revealed that mature females had lower carbon and higher nitrogen values than immature females and males with almost no isotopic niche overlap, whereas males and immature females had statistically similar values with overlapping niches. Terrapins and resources collected from island habitats contained higher carbon and nitrogen values than those from mainland habitats, with little overlap in niche between habitats. There were no significant temporal variations detected in either carbon or nitrogen values from terrapins between years, or within each habitat pre- and post-Hurricane Sandy. These findings suggest long-term terrapin foraging dynamics have remained relatively stable, signifying resilience to disturbance events within the study site.

Identification of nutritional composition and antioxidant activities of fruit peels as a potential source of nutraceuticals.

Fruit peels comprise several biologically active compounds, but their nutritional composition and antioxidant potential of different fruit varieties are limited. This study aimed to determine the nutritional composition and antioxidant properties of 12 peels of different fruit varieties such as apples, pomegranates, guavas, strawberries, grapes, and citrus fruits using a ultraviolet-visible (UV-Vis) spectrophotometer, an inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and an amino acid analyzer. The highest values of TPC, TFC, lycopene, ascorbic acid [total carotenoids and total antioxidant capacity (TAC)], reducing sugars, non-reducing sugars, and total soluble proteins were reported in grapes (Black seedless) 54,501.00 ± 0.82 μM/g dry wt., guava (Gola) 198.19 ± 0.46 Rutin equivalent dry wt., strawberry (Candler) 7.23 ± 0.33 mg/g dry wt., citrus (Mausami) 646.25 ± 0.96 ug/g dry wt., apple (Kala kulu-Pak) 14.19 ± 0.38 mg/g dry wt. and 12.28 ± 0.39 μM/g dry wt., strawberry (Candler) 25.13 ± 0.40 mg/g dry wt., pomegranate (Badana) 9.80 ± 0.43 mg/g dry wt., apple (Kala kullu-Irani) 30.08 ± 0.11 mg/g dry wt., and guava (Gola) 638.18 ± 0.24 mg/g dry wt. compared with its opponent peels of fruits, respectively. All 12 peels of the fruit verities had 20 amino acids and presented as dry matter basis%. The highest trend of glutamic acid + glutamine, glycine, and aspartic acid + asparagine was observed in pomegranate (Badana) 1.20 DM basis%, guava (Surhai and Gola) 1.09 and 1.09 DM basis%, and strawberry (Desi/local and Candler) 1.15 and 1.60 DM basis% in response to other fruit peels, respectively. Regarding the mineral profile, the highest values of nitrogen (764.15 ± 0.86 mg/100 g), phosphorus (53.90 ± 0.14 mg/100 g), potassium (3,443.84 ± 0.82 mg/100 g), ferric (1.44 ± 0.00 mg/100 g), magnesium (1.31 ± 0.00 mg/100 g), and manganese (0.21 ± 0.00 mg/100 g) were found in pomegranate (Badana), grapes (Black seedless), apple (Kala kulu-Pak), and pomegranate (Badana), respectively, in context to other fruit peels' extract. Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were analyzed for determining the correlation among different peels of fruits. Significantly, high levels of variation were noticed among different variables of peels of fruit. Fruit variety and its peels have been distinctive variables in selecting genotypes. The dendrogram obtained from cluster analysis was distributed into two groups and consisted of eight varieties in the same group, and four fruit varieties were in second group. Overall, the results conclude that fruit peels have the abundant antioxidants and some minerals, which can effectively be utilized for nutraceuticals as well as for food security.

Effects of leaf quality and colonization time on the abundance of bacteria in an experimental design

Small rivers, henceforth streams, depend on organic matter (nutrients and energy) from riparian vegetation. The quality of such allochthonous debris is determinant for the transformation of organic matter compounds, where the bacterial community has a crucial role in the final decomposition of the substrate. During bacterial colonization, debris with higher concentration of nutrients (more palatable) is prioritized, which accelerates the process. This study investigated the effects of leaf palatability of two native trees on bacterial colonization (abundance) over time, through a laboratory experiment that lasted 60 days. Values of C, N, P, C:N, C:P, polyphenols, tannins, lignin, lignin:N and leaf toughness of both species were compared. Bacterial abundance was higher in species with higher nitrogen values, although they had higher leaf toughness and more polyphenols, which differs from studies indicating that high leaf toughness represents low nutritional quality. The colonization time did not influence bacterial abundance. Therefore, processes degrading riparian vegetation and reducing nutritional quality can affect local decomposition, decreasing bacterial abundance.

THE EFFECT OF CHLORELLA SOROKINIANA UTEX 1230 AS A BIOFERTILIZER ON TOMATO CULTURE ROMEC 554J VARIETY CULTIVATED ON SANDY SOILS AT RDSPCS DĂBULENI

In the context of climate change, the use of microalgae is an alternative to meet the requirements of agriculture, food and renewable energy. A major area of application is the use of microalgae as biofertilizers in agriculture. The aim of this paper is to study the influence of the application of Chlorella sorokiniana UTEX 1230 inoculum on the evolution of soil chemical composition, as well as the ability of microalgae, as a biofertilizer, on the growth and development of tomato plants, including the influence on plant physiological indices. Ground determinations, at 60 days after application of Chlorella sorokiniana UTEX 1230 inoculum indicated higher values of nitrogen, phosphorus, potassium and organic carbon content in the soil, The results regarding the growth and development of the plants obtained in the protected area (solar greenhouse), for the Romec 554j tomato variety showed differences between the variants studied. The Romec 554j tomato variety recorded a higher rate of photosynthesis in the version treated with the inoculum of Chlorella sorokiniana UTEX 1230, compared to the control version and the technologically fertilized version (12,66 µmol CO2 / m2 / s, compared to 11,82 µmol CO2 / m2 / s in the control version and 12,48 µmol CO2 / m2 / s in the technologically fertilized version), but the values were not statistically assured.

Dynamics of humus forms and soil characteristics along a forest altitudinal gradient in Hyrcanian forest

Humus forms are good indicators of environmental conditions and thus important in forest ecological processes. Altitudinal gradients are considered as natural laboratory for evaluating soil ecological processes and humus form distribution. The objective of this study was to evaluate the macromorphology of humus forms along an altitudinal gradient (0-2000 m a.s.l.) covered with plain forest, mixed and pure forests and forest-grassland ecotone, in Alborz Mountains in northern Iran. In total, 225 humus profiles were evaluated. Forest stand variables including tree density, basal area, crown density, and height, forest floor and soil physico-chemical properties along with biological features were measured. We found that altitudinal gradients influence both humus forms distribution and soil properties but with different mechanisms. While soil properties (i.e., temperature, pH, CaCO3, soil N content, soil C/N and microbial biomass N) were significantly correlated with altitude, the forest floor properties were more influenced by tree species composition. Particularly, the abundance of Mull was decreased in plain mixed forests compared to mountain pure forests, whereas the frequency of Amphi was increased. Moreover, Oligomull and Leptoamphi were abundant in mixed beech forests, while Eumacroamphi, Eumesoamphi and Pachyamphi were only observed in pure beech forests. Such a distribution influenced soil fertility where higher values of nitrogen (N), microbial biomass nitrogen (MBN) and pH were observed at lower altitudes under mixed forests compared to pure forests at higher altitudes.

Evaluation of almond young trees growth and nutritional status under different slow-release compound fertilizer types and doses at Nubaria region

BackgroundSlow-release fertilizers (SRF) are quite numerous, and diverse group of materials are involved in the improvement of the effectiveness of fertilization, mitigation of the negative impact of fertilizers on the environment, and the reduction of labor and energy consumption connected with the application of conventional fertilizers. The objective of the experiment was to measure vegetative growth parameters and nutritional status of Nonpareil almond young trees under two types of slow-release compound fertilizers: Matador at 30, 60, and 120 kg/Feddan and Nitrophoska at (25, 50, and 100 kg/Feddan. The experiment was conducted in the Experimental Research Station of National Research Centre at Nubaria, El Behera governorate, Egypt, during successive growing seasons 2018 and 2019.ResultsThe results indicated that increasing doses of slow-release fertilizer significantly improved vegetative growth of trees. The highest dose of Nitrophoska had significantly higher stem length, diameter, numbers of branches and leaves/trees, leaf area, leaf chlorophyll content, leaf fresh and dry weight while the highest significant of specific leaf dry weight was obtained by applying the highest dose of Matador compared with control trees that received the fast-release fertilizer NPK 19:19:19 at 200 kg/Feddan. Leaf mineral contents of some macro (N, P, K and Mg) and micro elements (Fe, Mn, Zn, and Cu) were significantly increased as a result of application with slow-release fertilizers. Nitrophoska at 100 kg/Feddan gave the highest values of nitrogen, potassium, magnesium, and iron while Matador at 120 kg/Feddan gave the highest value of manganese. Matador at all doses resulted in a significant increment in phosphorus concentration in leaves in both seasons. Nitrophoska at 100 kg/Feddan and Matador at 120 kg/Feddan recorded the highest values of zinc and copper without significant differences between them.ConclusionsIt could be concluded that application with slow-release fertilizers resulted in a positive and significant influence on most investigated vegetative growth measurements and leaf mineral contents of Nonpareil almond trees, since the application with Nitrophoska at 100 kg/Feddan was the most effective treatment for increasing growth measurements and improving leaf nutritional status of Nonpareil almond trees grown under Nubaria condition.

FEATURES OF THE CHEMICAL COMPOSITION OF TOP HUMUS ACER NEGUNDO L. (SAPINDACEAE) IN CONDI-TIONS OF BREACHED BOTTOMLAND PHYTOCENOSES

Abstract: The article analyzes the results of the biochemical composition of top humus of various phytogenic zones of Acer negundo L. under the conditions of breached bottomland plant communities. Sampling was carried out on trial plots in various conditions of crown density, taking into account the zones of influence of trees. The outer zone of single trees was chosen as a control. Ash content was determined by dry ashing; the content of nitrogen and phosphorus - from one sample after wet ashing: nitrogen - according to the Kjeldahl method, phosphorus – according to the Murphy and Riley method; lignin accumulation – using 72% sulfuric acid solution. Statistical data processing and graphing were performed using the standard software package StatSoft STATISTICA 8.0. for Windows and Microsoft Office Excel 2007. Some features of the chemical composition of the top humus A. negundo in the conditions of breached bottomland phytocenoses are revealed. In single trees in unclosed stands in the subcrown and near-gutted zones, the largest amount of ash was found, while in trees with a crowns density of 50–60%, higher values of nitrogen, phosphorus and lignin were found in comparison with other groups of trees and with control. The most strongly differing indicator of the chemical composition of top humus at test sites was the content of ash and lignin, to a lesser extent the content of nitrogen and phosphorus varied. Experimental data can be used to assess the state of the ground cover and the formation of soil organic matter in forest communities.

EFFECT OF PLANTING DATES AND NITROGEN SOURCES ON DRY WEIGHT, YIELD AND NITROGEN USE EFFICIENCY OF GARLIC PLANTS GROWN UNDER SOUTH SINAI GOVERNORATE CONDITIONS

A field experiment was carried out during the two successive winter seasons of2014/2015 and 2015/2016 at a private farm in El-Tour region, South Sinai Governorate, Egypt, tostudy the effect of planting dates, nitrogen sources and their interactions on dry weight, yield and itscomponents and nitrogen use efficiency (NUE) of garlic (Balady cultivar) grown in sandy soil conditionsusing drip irrigation system. The obtained results could be summarized as follows: The interactionbetween planting dates on 15th Oct. or 1st Nov. and fertilizing plants with 100% of the recommendedrate (RR) of N as poultry manure (PM) or and 50% RR of N as ammonium sulphate (AS)+50% RR ofN as PM gave the highest values of each of dry weight of bulbs, leaves, and total dry weight/plant at135 days after planting (DAP), N and P uptake by bulbs and leaves and total uptake of them by plant,yield of grades 1,2, exportable, marketable, total yield, average bulb weight and the highest values ofnitrogen use efficiency (NUE). Whereas, the interaction between planting on 15th Oct. and fertilizingplants with 50% RR of N as AS + 50% RR of N as PM gave the highest values of K uptake by bulbsand leaves as well as K total uptake by plant.

Resveratrol Improves the Energy Sensing and Glycolipid Metabolism of Blunt Snout Bream Megalobrama amblycephala Fed High-Carbohydrate Diets by Activating the AMPK-SIRT1-PGC-1α Network.

This study investigated the effects of resveratrol on the growth performance, energy sensing, glycolipid metabolism and glucose and insulin load of blunt snout bream Megalobrama amblycephala fed high-carbohydrate diets. Fish (39.44 ± 0.06 g) were randomly fed three diets: a control diet (30% carbohydrate), a high-carbohydrate diet (HC, 41% carbohydrate), and the HC diet supplemented with 0.04% resveratrol (HCR) for 12 weeks. Fish fed the HC diet had significantly high values of nitrogen and energy retention efficiency, hepatosomatic index, intraperitoneal fat ratio, whole-body lipid content and intraperitoneal fat glycogen and lipid contents compared to the control group, but showed little difference with the HCR treatment. Liver and muscle lipid contents and plasma levels of glucose, glycated serum protein, advanced glycation end products and total cholesterol of fish fed the HC diet were significantly higher than those of the control group, whereas the opposite was found with resveratrol supplementation. Fish fed the HC diet obtained significantly low values of plasma insulin levels and hepatic adenosine monophosphate (AMP) contents and NAD+/NADH ratio compared to HCR treatment, but showed little difference with the control group. The opposite was found for hepatic adenosine triphosphate (ATP) contents and the ATP/AMP ratio. In addition, fish fed the HC diet showed significantly high transcriptions of glucose transporter 2 (GLUT2), glucose-6-phosphate dehydrogenase, glycogen synthase, fatty acid synthetase (FAS), acetyl-CoA carboxylase α (ACCα), peroxisome proliferator-activated receptor γ and PPARα compared to the control group, whereas the opposite was found for protein levels of AMP-activated protein kinase α (t-AMPKα), phosphorylated AMP-activated protein kinase α (p-AMPKα), sirtuin-1 (SIRT1), and p-AMPKα/t-AMPKα ratio as well as the transcriptions of AMPKα1, AMPKα2, SIRT1, PPARγ coactivator-1α (PGC-1α), phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase (FBPase), glucose-6-phosphatase, carnitine palmitoyl transferase I (CPT I) and acyl-CoA oxidase. Resveratrol supplementation significantly up-regulated the protein levels of t-AMPK, p-AMPK, and SIRT1, p-AMPK/t-AMPK ratio as well as the transcriptions of AMPKα1, AMPKα2, SIRT1, PGC-1α, GLUT2, FBPase, and CPT I compared to HC group, while the opposite was found for sterol regulatory element-binding protein-1, FAS and ACCα. Furthermore, resveratrol improved glucose and insulin tolerance of fish fed the HC diet after glucose and insulin load.

EFFECT OF PHOSPHATE FERTILIZATION AND SPRAYING WITH SEAWEED EXTRACT KELP 40 ON QUALITY, MINERAL CONTENT AND BACTERIAL NODULES IN TWO PEA CULTIVARS

This study was conducted in the vegetable farm/Hort. & land scape Dept./College of Agric. & Forestry / Mosul Univ. to study the effect of two levels of phosphate fertilization, zero, 40 kg P2O5/Donum, and spraying with three levels of seaweed extract, kelp 40, Zero, 2,4 ml/l in two pea cultivars namely: "Little Marvel and Fabreca". Plants were sprayed twice, the first one at 3-5 true leaf stage, whereas the second after 15 days from the first spraying. Results indicated that phosphate fertilization & seaweed extract showed a clearly effects in TSS, protein percentage of seeds, nitrogen & phosphorus concentrations of leaves, in addition to number of root nodules/plant. Phosphate treatment gave the highest protein percentage (30.08%), while spraying with 4 ml/l of seaweed extract resulted in the highest values of nitrogen, phosphorus concentrations in leaves, and the large number of root nodules/plant. The results revealed also that cultivars varied between them in all parameters studied.

Horticulturists and oxygen ecozones in the tropical and subtropical forests of Southeast South America

We analyse the isotopic values (δ13C, δ15N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T = 4.21; P = 0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ13Cco = −15.5 ± 1.8‰; δ13Cap −10.4 ± 0.8‰) and a depleted one in the Taquara ones (δ13Cco −18.2 ± 1.7‰; δ13Cap −11.9 ± 0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ15N 11.1 ± 0.6‰) compared to the Taquara samples (δ15N 9.3 ± 1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ18O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ18O −3.7 ± 0.5‰ (CV = 13.5%; CI = −3.83 / −3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ18O −1.5 ± 0.3‰ (CV = 16.5%; CI = −1.69 / −1.29). The isotopic data (δ13C, δ15N and δ18O) suggest human movements between these two ecozones.

Differences in Biogeochemical Properties and Microbial Activities in Stream Segments with Changes in Land-use Type

Changes in land-use type can affect soil and water properties in stream ecosystems. This study examined the effects of different land-use types on biogeochemical properties and microbial activities of a stream. We collected water and sediment samples in a stream at three different sites surrounded by varying land-use types; a forest, a radish field and a rice paddy. Nitrogen contents, such as nitrate, nitrite and total nitrogen in the stream water body, showed significant differences among the sampling sites. The highest nitrogen values were recorded at the site surrounded by cropland, as fertilizer runoff impacted the stream. Soil organic matter content in the sediment showed significant differences among sites, with the highest content exhibited at the forest mouth site. These differences might be due to the organic matter in surrounding terrestrial ecosystems. Microbial activities determined by extracellular enzyme activities showed similar values throughout all sites in the water body; however, the activities in the sediments exhibited the highest values near the forest site and mirrored the soil organic matter content values. From these results, we conclude that different land-use types are important factors affecting water and sediment properties in stream ecosystems.

You are not what you eat during physiological stress: Isotopic evaluation of human hair.

Variation in δ(13) C and δ(15) N values can be assessed to understand not only diet, but also the influence of physiological factors on an individual. The metabolic balance of an individual can impact isotopic signals in tissues that are forming during the periods of metabolic stress. Fluctuating δ(15) N values are associated with physiological stressors that alter an individual's metabolism such as infection, injury, or pregnancy. This study examines variation in δ(13) C and δ(15) N values along sequentially segmented hair in both modern and archaeological individuals. Subjects with an observable skeletal pathology, known chronic illness, or evidence of pregnancy were compared with controls exhibiting no evidence of physiological stress. The results on hair samples from individuals from 19(th) century Belleville, Ontario, four modern cadavers (two with cancer and two sudden deaths), and two living pregnant women indicate that δ(15) N values are approximately 1‰ higher in individuals with a pathological condition (e.g., infection, fracture, or cancer) and are 1‰ lower during pregnancy, whereas δ(13) C values show less variability. Higher nitrogen values may represent the recycling of nitrogen derived from the breakdown of existing proteins in the body (catabolism), whereas lower δ(15) N values are related to increased utilization of dietary and urea nitrogen for tissue synthesis during pregnancy. These findings suggest that short-term fluctuations of δ(15) N values may be the result of changes in an individual's metabolic balance, and that metabolic imbalance poses a confounding factor to ancient dietary studies when using rapidly growing tissues such as hair.

Crevice Interments Deconstructed

The discovery of two well preserved human crania in a crevice overlooking a spring fed creek near Austin, Texas, led to medico legal, archeological, and bioanthropological investigations aimed at understanding the context and biological affinity of the crania. Archeological excavations uncovered no evidence that the crania were interred in the crevice during prehistoric times. Skeletal analysis showed they were of Native American ancestry. Radiocarbon dating indicated they are contemporary to one another and probably date to the seventh or eighth century A.D. Measured stable isotopic rations of carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N) derived from human bone collagen samples from the crania are not consistent with other burial populations from the region, having higher nitrogen values than all other comparative samples. The crania also showed polish from repeated handling and several of the molars in one cranium had been glued in place. Taken together, these lines of evidence suggest the crania were removed from an unknown locality outside the Central Texas region, kept in a private collection, and placed in the crevice recently.

Bulk electrical conductivity as an indicator of spatial distribution of nitrogen and phosphorous at feedlots

The increasing demands of producing beef for domestic and international consumption is leading to the development of feedlots in Argentina. Unfortunately, the great amount of manure produces leachate of nitrates and other ions which may affect groundwater quality. The objective of this paper was to identify the spatial distribution of bulk electrical conductivity (ECb) of non-saturated zone and its association with variability of nitrates and bioavailable phosphorous, water content, topography and electrical conductivity of saturated paste extract (EC).The analysis of the impact was done at two pens with different time of confinement of the animals (Pen1 and Pen 2, with 16months and 7years of animal occupation, respectively). The initial exploration phase was done by electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys were subsequently performed at a subarea for studying the spatial distribution of ECb. A grid of soil sampling up to 1m depth was done at the same subarea of the EMI survey. A geostatistical interpolation of data was performed in order to map ECb, water content, nitrogen, bioavailable phosphorous and EC.Anomalies of higher conductivity (between 6 and 10 times the background values) were found near the feedbunk and the water trough, being greater on soils with larger period of manure recharge. Water content, nitrogen of nitrates (N-NO3−), bioavailable phosphorous (Pavail.) and EC showed patterns of spatial distribution similar to ECb. These patterns are mainly associated with the runoff movement of water to the lower zones in the case of a steeper slope and the soil compaction as in the Pen 1. In the Pen 2, the patterns of spatial variability are similar for ECb and water content while anomalies of high ECb were found along an abandoned feedbunk. High values of N-NO3−, Pavail. and EC were found at this site. A longer period of manure recharge resulted in higher values of nitrogen and bioavailable phosphorous in soils.It may be stated that bulk electrical conductivity was a good spatial indicator of water, nitrogen and bioavailable phosphorous in sandy loamy soils in these pens for the investigation depth of 1m. The bulk conductivity seems to be primarily associated with water content which is the path of transport of ions through the porous medium. In all the cases, the major contents of nitrogen and bioavailable phosphorous in the soil were associated with high bulk electrical conductivity when water content was above an equivalent depth of water of 100mm. The soil moisture status should be taken into account before an electromagnetic exploration for detecting soil contamination. Regarding the impact on groundwater pollution, the proximity of the water table to the surface seems to be more influential than the animal stocking rate for a longer period.

Leucaena macrophylla: An ecosystem services provider?

Leucaena macrophylla, a tree native to southern Mexico’s tropical dry forest, belongs to a genus that is popular worldwide as a component of agroforestry systems. However, despite appreciation by local communities, this species is poorly studied and has not been evaluated as a multipurpose tree in its native range. This work evaluated whether L. macrophylla has the qualities necessary to serve as a multipurpose tree for agroforestry systems and a provider of ecosystem services in its original distribution, specifically, in soil nutrient amelioration and recovery, fuelwood production, and provision of quality livestock fodder. Leaves contained high values of nitrogen and calcium, and litter decomposition was relatively rapid (~50 % of mass lost over first 6 months). Despite somewhat low wood density, this species’ high calorific value and low ash and moisture contents yielded a relatively high firewood value index (FVI = 2,594.65), suggesting high potential as a fuelwood. In terms of fodder quality, protein and digestible fiber contents were high and in vitro digestibility was adequate, as was condensed tannin concentration. It is important to mention, however, that L. macrophylla showed higher-than-ideal contents of lignin, both in fresh leaves and in litter. However, this apparently does not drastically reduce overall quality (i.e. decomposition rate and in vitro digestibility), and appropriate management techniques such as composting can mitigate its effects. Given its potential for providing a variety of ecosystem services, we recommend that L. macrophylla be installed in agroforestry systems in its native range to evaluate its effect on crop productivity.

Pollution de l’eau souterraine et risques sanitaires à Yaoundé au Cameroun

The aim of this article consists of developing an ecosystemic approach to collect information about groundwater pollution in order to determine its origin and infer the health risks in Mingoa's watershed through the study of 12 spontaneous settlements. From an environmental point of view, family interviews and direct observations allowed us to inventory springs, wells and latrines, and to collect information. So, we have selected, on the basis of predefined criteria, 21 wells and springs for physico-chemical and bacteriological laboratory analyses. Two hundred children aged less than 5 years were subjected to KOAP examination. A number of 1224 latrines were inventoried, for an average use of 15 people per latrine, producing 913.3kg/year of excreta. Most of 91% of people use these latrines. The superficial aquifers, connected to the wells and springs, present high values of nitrogen, phosphorous pollutant and fecal contamination indicators (coliforms and fecal streptococcus), which make water inappropriate to human consumption. PCA analysis establishes that water pollution comes mainly from traditional pit latrines. The overall prevalence of diarrhea and parasite infestation was important (=40%). The presence of cysts of Entamoeba histolytica, Ascaris limbricoides, and Entamoeba coli confirms this high prevalence and testify to very approximate hygiene and environment conditions.

Recent findings regarding non-native or poorly known diatom taxa in north-western Italian rivers

Diatoms of the major rivers of North-Western Italy were investigated to highlight the presence of species of particular ecological interest but not as yet recorded. The survey area included streams belonging to seven different hydroecoregions (HERs) with a wide range of physical characteristics. Between 2008 and 2010, 200 samples were taken for the study of the diatom community composition, while a larger set of samples was examined to determine the presence or absence of the nuisance diatom species Didymosphenia geminata (Lyngbye) Schmidt. A specific field study was performed in two rivers characterized by persistent blooms of this species to evaluate the effects of its proliferation on the benthic communities. D. geminata was present in almost 20% of the samples. From a comparison with published data, we can confirm that D. geminata has recently been expanding its ecological range, as it has been found also in mesotrophic lowlands water. In some instances the formation of massive proliferation has been recorded. The calculation of autecological values confirmed its preference for oligotrophic waters with low mineral content and organic loading, although with a wider ecological amplitude than recorded in the first studies on this species. Another four taxa of particular interest were detected: Achnanthidium subhudsonis (Hustedt) Kobayasi (in 15 sites), Cymbella tropica Krammer (11 sites), Mayamaea cahabaensis Morales and Manoylov (2 sites) and Reimeria uniseriata Sala, Guerrero and Ferrario (18 sites). The first three species must be considered new records for Northern Italy. A. subhudsonis and C. tropica reached up to 20% relative abundance. From the analysis of their distribution and autecological values, we can assert that A. subhudsonis and M. cahabaensis show a preference for high values of nitrogen, this latter preferring also quite high values of total phosphorus. C. tropica prefers intermediate values of nitrogen nutrients and R. uniseriata is the least demanding species in terms of water quality. All the taxa studied have a wide ecological range, confirming their potential invasive behaviour. Finally, considerations are provided with respect to Italian and European historical data in order to understand whether these species can be considered non-indigenous and/or bloom forming, in the study area. The results may help improve the process of ecological classification of water bodies in the seven HERs, and the water protection actions introduced by the Water Framework Directive (2000/60).

Large-scale patterns of river inputs in southwestern Europe: seasonal and interannual variations and potential eutrophication effects at the coastal zone

We provide data on nutrient export for 28 rivers in southwestern Europe and analyze long-term changes in the context of anthropogenic pressures and regulation policies. Special attention is given to seasonal variations, because the integrated annual values that are usually provided do not allow us to establish comparisons with seasonal phytoplankton dynamics. The eutrophication risk associated with river inputs is addressed by means of an indicator (Index of Coastal Eutrophication Potential, ICEP, Billen and Garnier, Mar Chem 106:148–160, 2007). An overview of the temporal evolution and the intra-annual variability of the ICEP is discussed for specific rivers and integrated coastal regions. The annual dynamics of the eutrophication indicator is analyzed to delimit those periods when the risk of eutrophication is particularly high. The trends in nutrient fluxes and coastal phytoplankton are compared by means of a case study (Seine Bay). The decrease in phosphorus matches a general decrease in phytoplankton biomass in the summer. However, sustained high values of nitrogen still foster the emergence of harmful algal blooms, and we found an increase in the summer abundance of dinoflagellates. The abatement of phosphorus alone is not enough to shortcut harmful blooms and toxic outbreaks in the Seine Bay. A reduction in nitrogen inputs may be necessary to effectively minimize eutrophication problems.