Contents Of Available Nutrients Research Articles

Function of geophagy as supplementation of micronutrients in Tanzania

Geophagy is defined as the practice of eating soil and is observed worldwide. In Tanzania, edible soil sticks called pemba are consumed mainly by pregnant women, but the physiological function of eating pemba has not yet been elucidated. The objectives of the present study were to evaluate the physicochemical properties of edible soil sticks compared with ordinary soils in Tanzania and to evaluate the function of geophagy in terms of micronutrient supply and the adsorption capacity of materials such as toxins. The color of eight pemba samples collected from various markets was reddish or whitish and their shape was generally columnar with an average length, width and weight of 6.1 cm, 1.8 cm and 22 g, respectively. Pemba had a more clayey texture (48% clay on average) than the ordinary soils investigated for comparison, and the clay composition was generally dominated by kaolinite. The concentrations of available nutrients in pemba, extracted with 0.1 mol L−1 NaCl (pH 2), were 391 mg Ca kg−1, 234 mg Mg kg−1, 17 mg Mn kg−1, 6.5 mg Fe kg−1, 4.9 mg Cu kg−1, 2.8 mg Co kg−1, 1.9 mg Zn kg−1 and 1.1 mg Ni kg−1, and extraction with reductant drastically increased the amounts of Fe and Mn released. The amount of available nutrients supplied by pemba consumption at a rate of 50 g day−1 amounted to 99% of Mn and 13% of Fe in the case of reddish pemba and 75% of Cu in the case of whitish pemba of the daily requirement by pregnant women, suggesting the potential of pemba to supply these micronutrients. A moderate cation exchange capacity (CEC) level (11.1 cmolc kg−1) and lower ratio of CEC to clay content for the pemba compared with the soils indicated that the adsorption capacity was not the main criteria for choosing soil materials and instead fine-textured soils with kaolinitic clay mineralogy were deliberately chosen for pemba. In conclusion, the main function of eating pemba in Tanzania, and probably the original function of geophagy, is the supply of micronutrients, such as Mn, Cu and Fe, rather than the adsorption of toxic materials.

CRUSHED ROCKWOOL AS A COMPONENT OF GROWING SUBSTRATES

CRUSHED ROCKWOOL AS A COMPONENT OF GROWING SUBSTRATES

Extraction study of algal pigments in river bed sediments by applying factorial designs

Phytopigment content of river bed sediments changes in response to different concentrations of available nutrients and results in a useful descriptor of their trophic state and environmental quality. In this work three incomplete factorial designs of experiments were carried out for extracting algal pigments from river sediments using dimethylsulphoxide (DMSO), methanol or acetone. The independent variables used in this study and their variation limits were: extractant:sediment ratio (1–5 mL/g), temperature (40–80 °C) and duration of treatments (30–90 min). The experimental data obtained (chlorophyll- a, chlorophyll- b and total carotenoids content) allowed the development of empirical models for each phytopigment, describing the interrelationship between operational and experimental variables by equations, including linear, interaction and quadratic terms. The experimental results obtained showed that methanol and acetone were less effective extractants for phytopigments from river sediments when compared to DMSO. The model predicted that in a single extraction using 3.6 mL of DMSO/g of sediment at 38 °C during 40 min, DMSO releases the 89% of chlorophyll- a in the range tested, whereas the best conditions for extracting chlorophyll- b and total carotenoids are achieved using 3.6–3.7 mL of DMSO/g of sediment, at 64–67 °C for 50–51 min, respectively, releasing the 76% of the chlorophyll- b and the 100% of the total carotenoids in a single extraction.

Estimation of nutrient values of pig slurries in Southeast Spain using easily determined properties

The contents of available nutrients in pig slurries are not easy to quantify in situ without laboratory facilities, but chemical analyses using standard laboratory methods also take time and are costly and not practical for most farms. Thus, when animal slurries are applied to land, their fertiliser potential is often unknown. In addition, in the last years, the changes in the management of industrial piggeries has changed the nature of the pig slurries vg. decrease of the dry matter content, and consequently the methods and equations used for estimating the nutrient contents in these residues must be checked. In our study, slurry samples were collected from the storage tanks of 36 commercial farms in Southeast Spain. Samples were analysed for pH, electrical conductivity (EC), redox potential (RP), specific density (D), total solids (TS), sedimentable solids (SS), biological oxygen demand (BOD 5), chemical oxygen demand (COD), total nitrogen (TKN), ammonium nitrogen (AN), organic nitrogen (ON), and total contents of phosphorus, potassium, calcium and magnesium. Relationships between major nutrient levels of pig slurries and a range of physical and chemical properties were investigated. We also analysed the variability of pig slurries according to the production stage. TKN, AN and K were closely related to EC. The P content in slurries was related more closely to solids-derived parameters such as D. The use of multiple properties to estimate nutrient contents in pig slurries, especially for AN and K, seemed unnecessary due to the limited improvement achieved with an additional property. Therefore, electrical conductivity seemed to be the most appropriate single, easily determined parameter for estimation of total and ammonium nitrogen and potassium in pig slurries, with more than 83% of the variance explained. P seemed to be the worst key nutrient for estimation using any easily determined parameter.

Coliform dynamics and the implications for source tracking.

In many parts of the world, coliform counts in recreational waters are unacceptably high. In an attempt to rectify this problem, programmes are under way to develop methods that will allow the sources of the faecal contamination thought to be responsible for these elevated counts to be identified. The success of these efforts depends on the validity of several assumptions that underlie many of the proposed methods. One of the critical assumptions is that the clonal composition of the coliform species being monitored in a water body reflects the clonal composition of the species in the host populations responsible for the faecal inputs into that water body. To determine the extent to which among-strain variation in a coliform species might invalidate this assumption, a series of simple mathematical models was proposed and analysed. The first series of models assumed that all cells of species were identical. The question posed was - is the density of a coliform species in a body of water linearly related to the rate at which cells of the species enter the water body via faecal production? The results of these models suggest that, over a wide range of conditions, cell densities in the water body are linearly related to the rate at which cells enter the water body as a result of faecal contamination. This outcome occurs whether or not cells are capable of division in the external environment. When the rate of cell division depends on the concentration of available nutrients then, when nutrient input rates are 'high' and rates of faecal contamination are 'low', this linear relationship does not hold. The second series of models assumed that the coliform species consists of different strains and that these strains differ in their performance in the external environment. The results of these multistrain models show that the relative abundance of strains in the external environment is unlikely to reflect their relative abundance in the faecal inputs to the environment. Consequently, statements such as - domestic animals are responsible for 30% and wildlife for 70% of the faecal inputs to a water body - may well be meaningless.

New technologies and improvement of nursery stock quality

This four years experimentation work was aimed at research on using various waste organic materials and especially timber bark in cultivation substrates as a substitute of peat. Sixty-four special isolated cultivation beds were established for this purpose, each of 4.8 m<sup>3</sup> volume, in which 11 variants of substrates consisting of different proportions of different components in several replications were tested. Standard substrates Horticultural substrate B and RKS I. were used as controls. Another variant was used as a control for growing tests of plants in containers. All tested substrates were enriched with hydroabsorbent TerraCottem. In some variants reserve fertilisers with slow release of nutrients (Silvamix Forte) were applied. For cultivation testing of studied substrates four ornamental tree species (Alnus glutinosa, Fraxinus excelsior, Salix alba, Salix matsudana) were chosen. The best evaluated variants were the ones containing 50 and 75% of bark in combination with sand. The worst was the variant composed of chips and sawdust. Thanks to the use of hydroabsorbents, even the variant containing 100% of sand appeared to be very good. The tested trees had different reactions to the different types of substrates depending on their species requirements. The limiting growth factor for Alnus was the content of water in the substrate. Similarly, the content of available nutrients in the substrate was essential for Fraxinus. The hardwood cuttings of Salix not only rooted into the substrate in a few weeks, but also formed aboveground parts of the required sizes. Obtained data on growth parameters differed according to the diversity of requirements of the different studied species.

Root Architecture and Root:Shoot Allocation of Shrubs and Saplings in Two Lowland Tropical Forests: Implications for Life-Form Composition1

Entire root systems of saplings of five canopy species and of six shrub and treelet species growing in lowland mixed dipterocarp forest at Andulau, Brunei were excavated and measured. Referring to a prior study at Gigante, Panama, two-way, fixed-factor ANOVAs were used to compare life-forms and sites. Rooting depth and the proportion of root surface area in the upper 20 cm of soil did not differ significantly between life-forms because some treelets/shrubs at Andulau were deep-rooted; all saplings studied were deep-rooted. The root:leaf area ratios of both saplings and treelets/ shrubs at Andulau were significantly higher than those at Gigante. We attribute this strong difference to the lower soil content of available nutrients at Andulau where rainfall shortage is less severe and regular than at Gigante. Available data on life-form composition and mortality rates in large plots are consistent with our proposal that shallow-rooted shrubs and treelets are more vulnerable to drought than deep-rooted life-forms. We suggest that future studies of water use partitioning, wood anatomy, leaf morphology, and associations with neighboring plants would benefit from an explicit examination of their relation to rooting depth.

The effects of grazing and burning on soil and plant nutrient concentrations in Colombian p�ramo grasslands

The impact of extensive livestock farming on the physical and chemical characteristics of the volcanic soils and on the nutrient status of green plant tissues of neotropical alpine grasslands (páramo) is studied. Soil and plant samples were taken over a one-year period at five sites with different agricultural (grazing and burning) management. In the undisturbed páramo ecosystem, soil moisture (50–250%) and organic matter content are high (7–27%) and decomposition (11–35% yr-1) and element concentrations are low. Low temperatures (max < 10°C) and phosphorus fixation by the soil (5 mg P g-1 soil) determine the low mineralization and turn-over rates.Multivariate analysis of laboratory results indicates that the season of sampling and the agricultural practice are the most important explanatory factors for variation of soil characteristics. After long-term heavy grazing, soils have a higher bulk density and a lower moisture content. The outcome of a litterbag experiment confirms the hypothesis of higher decomposition rates at grazed sites. In the intermediate (wet-dry) season, conditions were somewhat better for plant growth but the system remained nutrient limited.Surprisingly, no relation between soil density, moisture or carbon content and concentrations of available nutrients in the soil is found. This is supported by the rather uniform nutrient concentrations in green plant tissue among the sites. It is concluded therefore that the effect of burning and grazing on páramo soils is principally restricted to physical characteristics, and that differences in chemical characteristics of the soil do not cause differences in vegetation structure between grazed, burned and undisturbed sites.

Nutrient Uptake from Enriched Soil Microsites by Three Great Basin Perennials

Relative nutrient uptakes efficiency was measured using a dual—radiotracer (32P and 33P) technique for Agropyron desertorum, Artemisia tridentata, and Pseudoroegneria spicata, species from the arid shrub—steppe of the Intermountain Region in the western U.S. These species differed in the timing and magnitude of their response to experimentally enriched soil microsites. The most rapid and significant increase in the uptake of phosphorus tracer from enriched microsites was exhibited by Agropyron, followed by Artemisia, while there was only a trend toward an increase in uptake for Pseudoroegneria. The volume of soil enriched was only 4% of the total pot volume yet Agropyron extracted more phosphorus from the enriched microsite than was removed from the remainder (96%) of the soil volume based on tracer uptake from enriched and unenriched microsites. For Agropyron and Pseudoroegneria, plant uptake of phosphorus from microsites was approximately proportional to the soil microsite enrichment and all three species exhibited increased root length density within the microsites in proportion to the concentration of available nutrients. Integrated physiological and morphological response of the plants to nutrient enrichment increased phosphorus uptake, normalized to the amount of phosphorus available in the soil microsites, by 19.7 to 97.5 x compared to uptake from a similar volume of unenriched soil. Preferential allocation of recently assimilated carbon to roots within enriched soil microsites was also demonstrated. The most important differences detected among species were associated with the temporal flexibility they exhibited in response to enrichment of soil microsites. Differences in flexibility and response among these species have been reported for other aspects of nutrient uptake, suggestive of species—specific differences contributing to demonstrated differences in productivity, persistence, and competitive ability.

Nutrients and mass in litter and top soil of ten tropical tree plantations

The importance of litter to nutrient and organic matter storage and the possible influence of species selection on soil fertility in ten stands each consisting of a separate tree species were examined in this study. The plantations had been grown under similar conditions in an arboretum in the Luquillo Experimental Forest, Puerto Rico. The species involved were: Anthocephalus chinensis, Eucalyptus × patentinervis, E. saligna, Hernandia sonora, Hibiscus elatus, Khaya nyasica, Pinus caribaea var. hondurensis, P. elliottii var. densa, Swietenia macrophylla, and Terminalia ivorensis. After 26 yr, litter mass ranged from 5 mg ha-1 in the H. sonora stand to 27.2 Mg ha-1 in the P. caribaea stand. Nutrients in the litter (N, P, K, Ca, and Mg) also varied widely, but stands were ranked in different order when ranked by nutrients in the litter than then ranked according to accumulation of mass. Only E. saligna and A. chinensis stands were ranked similarly in accumulation of both nutrients and mass, and the stand of H. elatus was ranked higher with respect to nutrient accumulation than to accumulation of mass. The nutrient concentration in standing leaf litter generally increased in the order of recently fallen <old intact< fragmented. Nutrient concentration of standing leaf litter appears to increase with age and depth in the litter layer. The amount of nutrients stored in the litter compartment of these plantations was in the same order of magnitude as the quantity of available nutrients in the top 10-cm of mineral soil. Total litter mass was negatively correlated with the mass-weighted concentration of N, K, and Mg. The same relationship was found for Ca in the leaf litter and N in the fine wood litter compartments. In some stands (notably P. caribaea, P. elliottii, and E. saligna), leaf litter derived from species other than the species planted in that particular stand had higher nutrient concentration than leaf litter from the planted species. Soils of the 10 stands were classified in the same soil series and had similar texture (clay soils). However, significantly different chemical characteristics were found. Results obtained by analysis of covariance and by limiting comparisons to adjacent stands with similar soil texture, indicate that different species have had different influences on the concentration of available nutrients in soil.

Nutrient status of apple orchards in Canterbury, New Zealand. 1. Levels in soil, leaves and fruit and the prevalence of storage disorders

Abstract The nutrient status (N, P, K, Ca, Mg, K, Fe, Mn, Zn and Cu) of 26 Cox's Orange Pippin and 20 Braeburn apple orchard sites in the Canterbury region of New Zealand was evaluated by soil, leaf and fruit analysis. Concentrations of available nutrients in soils ranged widely but those in leaves and fruit were generally confined to a relatively narrow range. Concentrations of leaf N were high in the study area, as were levels of extractable soil P, and it is suggested that reductions in fertilizer additions of these nutrients would generally be appropriate. Soil, leaf and fruit nutrient contents were generally not well correlated with one another. The only highly significant correlations (P≤0.001) were between leaf and fruit Ca for Cox's and soil and fruit Mg for Braeburn. The poor correlations were attributed to the empirical nature of soil tests, the presence of large nutrient reserves within the tree framework and the effects of cultural and environmental factors on nutrient uptake and translocation by the trees. The storage disorders bitter pit and senescent breakdown in Cox's and lenticel blotch pit in Braeburn were observed in apples harvested from some of the study sites. Such disorders were generally associated with low concentrations of Ca (≤.2.5 mg/100 g) in samples of cortical plugs taken from fruit at harvest.

INFLUENCE OF DIETARY MANIPULATION ON THE DETRIMENTAL EFFECTS OF MOLD-CONTAMINATED BARLEY FED TO GROWING CHICKS

The effects of feeding Penicillium cyclopium and Aspergillus flavus contaminated barley on Leghorn chicks were examined. Mycotoxin screening determined the mold-contaminated barley to be free of suspect toxins. This study examined the hypothesis that the effects of mold-contaminated barley are due to a deficiency of readily digestible nutrients, or some other factor. Chicks were fed diets containing either mold-free barley, a non-nutritive bulk (cellulose) plus mold-free barley, or a mold-contaminated barley (7% mold), in combination with low (2%) or high (10%) dietary tallow and supplemental starch (0 and 15%). High fat and starch supplementation both resulted in slightly higher weight gains for birds fed the mold-contaminated barley and cellulose containing diets, but the maximal improvement values were still more than 60 and 20%, respectively, lower than birds given a 6.7% tallow reference diet. Neither fat nor starch affected feed consumption. Birds fed the cellulose diet performed about 100% better than those given mold-contaminated barley, despite a theoretically lesser concentration of available nutrients in the former. Results of this study suggest the presence of some unidentified factor(s) in mold-contaminated. Key words: Mold-contaminated barley, mycotoxin, chick performance, starch, fat

Substrate usage and odours in mushroom composting

Odour problems associated with producing a composted substrate for mushroom culture were considered at 9 Australian farms, in relation to composting batch recipes. Effects of usage of nutrient rich composting activators were evaluated using nitrogen (N) concentration ratios (%) and a novel ratio, the C/A ratio as indicators of compost nutritional status. The CIA ratio segregated composting ingredients into nutritional classes. Both % N and the C/A ratio showed that excess nutrient usage was positively correlated with odours. Both correlations were significant at P= 0.01. Final % N, however, did not increase with higher initial % N values. This investigation indicates that reducing excessive initial concentrations of available nutrients in compost formulations can reduce odours, while not necessarily reducing compost quality in terms of final N level.

The influence of upwelling on South African west coast seaweeds

Upwelling from the Benguela Current system on the South African west coast has produced a seaweed flora distinct from that in the region east of Cape Agulhas. The origins of the major red algal component of the West Coast flora appear to be in temperate and polar regions of the southern Pacific Ocean, whereas the South and East Coast floras are more closely related to the floras of the tropical Indian Ocean and of South and West Australia. Although the West Coast flora has a high degree of endemism, recent evidence suggests that events since the initiation of the Benguela system < 12 million years ago have been crucial in its formation. Evidence on the effects of upwelling on growth and physiology suggests that rapid irregular fluctuations in temperature and nutrients on the West Coast have little effect on the strongly seasonal patterns of development, which are probably brought about by aspects of the light regime. Variations in light intensity in the sublittoral caused by upwelling or downwelling conditions appear to have relatively minor effects on seaweed production. Little is known of the effects of high concentrations of available nutrients in upwelled water, although the kelp Ecklonia maxima appears to have evolved both morphologically and physiologically to the West Coast conditions.

Effect of lime and phosphorus applications on concentrations of available nutrients and on P, Al and Mn uptake by two pasture legumes in an acid soil

Effects of increasing rates of lime and phosphorus addition on concentrations of available nutrients in soil and on P, Al and Mn uptake by two pasture legumes, lotus (Lotus pedunculatus Cav.) and white clover (Trifolium repens L.), were studied in a pot experiment using a highly leached acid (pH 4.2) soil.

Numerical taxonomy and ecology of oligotrophic bacteria isolated from the estuarine environment.

Slow-growing bacteria, isolated on nutrient-rich and nutrient-limited media, from Chesapeake Bay water and sediment samples, were examined for 119 biochemical, cultural, morphological, nutritional, and physiological characters. Those bacteria which grow on low nutrient media, termed oligotrophs, a total of 162 strains, were subjected to taxonomic analysis, as a preliminary step in determining their ecological significance. The data for all strains included in the study were examined by computer and the simple matching (S SM) and Jaccard (SJ) coefficients calculated. Clustering was achieved by the unweighted average-linkage method. From sorted similarity matrices and dendrograms, 148 strains, 90% of the total, were recovered in 24 phenetic groups defined at the 80 to 85% similarity level. Only 12 phena could be presumptively identified and these included representatives of Alcaligenes, Corynebacterium, Hyphomicrobium, Hyphomonas polymorpha, Listeria, Nocardia marina, Pedomicrobium, Planococcus citreus, Sphaerotilus, Streptothrix, and Streptomyces. Of the remaining organisms, 10% were unidentified sheathed bacteria. It is concluded that slow-growing bacteria are distributed throughout the estuarine environment and can account for a large proportion of the colonies observed on media after prolonged periods of incubation. The oligotrophic bacteria appear to predominate in areas where the concentration of available nutrients is low and are more characteristic of non-eutrophic aquatic systems.

Ant (Formica exsectoides) Pedoturbation in a Forest Soil

AbstractTwenty‐five active mounds of the common eastern moundbuilding ant (Formica exsectoides) had an average height of 0.37 m and basal diameter of 1.1 m in a long, narrow neverplowed clearing of 1,040 m2 on the edge of a woodland in southern Wisconsin. The mound volume ranged from 0.01 to 0.6 m3 and averaged 0.13 m3. The ant nests, extending at least 160 cm below the soil surface occupied 1.9% of the area of the surface of a Typic Hapludalf (Gray‐Brown Podzolic), Dubuque silt loam, formed in thin loess over reddish cherty clayey residuum on dolomitic limestone. Mounds were virtually bare and were largely composed of silty clay. Detailed studies were made of a soil profile through a large mound and of an intermound soil profile nearby. Calculations indicated that the ants have moved to the surface the equivalent of 1.25% of a plow layer or 2,500 kg of soil (dry wt) per 1,040 m2 and in the process have reduced the bulk density of the material from 1.5 to 0.8 g/cm3 and increased the contents of available nutrients in the soil. Voids 0.2 to 2.3 cm in diameter, on the average occupied 20% by volume of the mound and about 10% of the buried A horizons. The mound contained about 50% silt, 46% clay, 4% sand; 4% free iron oxides, and 3% organic matter. Corresponding figures for the A2 and IIB23 horizons of the Dubuque are: 78, 18, 4; 2 and 3; 15, 83, 2; 6 and 0.3. Disturbance of soil profiles by this species of ant is restricted to small areas, apparently because colonies are established and mounds developed only in temporary openings in forests.

Evaluation of factors affecting survival of Escherichia coli in sea water. V. Studies with heat- and filter-sterilized sea water.

The bactericidal action of sea water was measured as the difference in survival of cells of Escherichia coli in untreated and autoclaved portions of water samples. The beneficial effect of sterilization by heat on the survival of E. coli in sea water varied with season and was most marked during summer months, however, the magnitude of the effect differed greatly from sample to sample. The more obvious and commonly suggested explanations for the bactericidal action of sea water were tested experimentally. The pH and salinity of sea water were changed by autoclaving, but the direction of the former was detrimental rather than beneficial and the significance of the latter was not clarified. The survival of cells of E. coli in filtered portions of some water samples was greater than that in untreated portions and equal to that in autoclaved portions, indicating that predators and competitors removed by filtration had contributed significantly to the rapid death of the bacterium in the untreated water. However, in the majority of samples tested, survival of E. coli in autoclaved water was considerably greater than survival in filtered water. The possibility that the beneficial effect of autoclaving over and above that of filtration resulted from inactivation or destruction by heat of bacteriophages and thermolabile toxic substances such as antibiotics was considered. Moreover, the suggestion was tested that the increased survival of E. coli in autoclaved sea water was due to the ability of heat to disrupt and degrade microbial cells and thermolabile compounds and, thereby, to cause an increase in concentration of available nutrients in sea water. It was concluded that the bactericidal action of sea water is not explicable in terms of the destruction or inactivation by heat of bacteriophages or antibiotics. Although added organic matter influenced the survival of E. coli, the test organism was not an effective competitor in sea water and the nutrient levels required to offset the bactericidal action were excessive. Artificial sea water was demonstrated to exert a bactericidal action comparable to that of natural sea water. Low levels of cysteine which favor survival of E. coli in natural sea water had a similar effect in artificial sea water. Nevertheless, it is not at this time possible to conclude that the factors responsible for the bactericidal action of artificial sea water are identical with those responsible in natural sea water.