The impact of clonality on an endangered tree (Elaeocarpus williamsianus) in a fragmented rainforest

The occurrence and distribution of clonality in the endangered rainforest tree Elaeocarpus williamsianus (Elaeocarpaceae) was investigated using SSR and RAPD analyses for 170 apparent individual trees found across seven sites. The results obtained with the two molecular techniques were in complete agreement in showing that single clones are present in most of the E. williamsianus sites with two genets occurring at the largest and most adequately protected site. In addition, seed production, viability and germinability were determined for four of these populations. Fruit were produced in all four populations tested although sterile fruit were very common. Only two E. williamsianus trees representing different genets within the same site produced viable seed. The overall genetic diversity within E. williamsianus is much lower than expected and thus the potential for sexual reproduction has been significantly diminished. It is concluded that habitat fragmentation removed an existing balance between vegetative and sexual reproduction in this species. Such findings have added urgency to the management of this species which could include a reintroduction program incorporating the collation of all clones within selected sites.     

Nutritional value of a highly digestible sorghum cultivar for meat-type chickens

The nutritional value of a newly discovered sorghum mutant cultivar (P851171), with high in vitro protein digestibility, was compared to those of corn and two normal sorghums (P721N and 611Y) in two chick feeding trials. Although 8-20 day protein efficiency ratios and net protein ratios of all three sorghums were inferior to those of corn, P851171 and 611Y had markedly greater mean true amino acid digestibilities (TAAD) than either corn or P721N. In a subsequent 42-day experiment, all three sorghums supported weight gains equal to those of the corn-fed chicks. Feeding suboptimal levels of dietary protein resulted in reduced weight gains and no observed benefits of P851171 or 611Y. Furthermore, chicks fed P851171 exhibited poorer feed/gain values as compared to those fed the other cereals. It is possible that the starch content/carbohydrate profile of P851171 was inferior to that of the other sorghums, which offset its superior TAAD and resulted in poorer broiler performance.     

Displacement imaging in porous media using the line scan NMR technique

Displacement imaging is a recent, powerful NMR method with which distributions of displacements can be acquired of e.g. fluids within a porous medium. Both motion parallel and perpendicular to the flow direction may be observed within a time window of a few milliseconds to several seconds. By combining displacement imaging with the line scan technique, one-dimensionally resolved measurements with a high temporal resolution ( < 1 min) of the spatial dependency of motion can be obtained. Here we present displacement images of flow through two simple model systems for soil: an unconsolidated glass bead water system and a sintered glass bead filter. It is demonstrated that the combination of displacement imaging and spatial resolution along a line is important to access both bulk displacement and local displacements in relation to the local porosity.     

Hydrochemical processes at a pristine site in nord-trøndelag,mid-Norway

A detailed study of hydrochemical processes associated with vegetation and soils was undertaken at a pristine site in mid-Norway. Inputs to the site during snow-free periods showed a marked seasonality with excess sulphate concentrations in rainfall only during the summer months. However, this represented a small fraction of total annual loading and there was a dominant influence of sea salt deposition. Site vegetation modified the chemistry of water reaching the soil surface, and this also showed a marked seasonal response. The pristine nature of this site results in the soils retaining acid-soluble components which may have been eluted from impacted sites. In the soils, the extractable aluminium remains largely (70%) in the organic bound forms. The contribution of different sources of water in affecting streamwater output quality at this site are discussed.     

Cross-enhancement: enhanced biodegradation of isothiocyanates in soils previously treated with metham sodium

Rates of degradation of 2-propenyl isothiocyanate (PrITC), benzyl isothiocyanate (BeITC) and 2-phenylethyl isothiocyanate (2-PeITC) in a soil known to biodegrade methyl isothiocyanate (MITC) at an accelerated rate, but never previously exposed to the other ITCs, were higher (persistence in soil increased by 1150, 80 and 100%, respectively,) than in a similar non-degrading soil. The rate of degradation of the same three ITCs was significantly lower in sterilised (autoclaved) soils than in the degrading soil. These results indicate that the three ITCs are susceptible to enhanced cross-biodegradation in soils where enhanced biodegradation of MITC has been induced by use of metham sodium soil fumigant. When Brassica plant tissue containing sinigrin (2-propenyl glucosinolate) as the predominant glucosinolate (GSL) was added to the degrading soil, the amount of PrITC present after 24 h was significantly lower than in the non-degrading soil at the same amendment rates. The toxicity to an insect test organism of the PrITC produced from the biofumigant plant tissue was correlated with the concentration of PrITC measured in the two soils, with 67% more plant tissue required in the degrading soil to cause 100% mortality as in the non-degrading soil (3.0 vs 5.0 mg g⁻¹). The effectiveness of biofumigation using ITC-producing Brassica plants may be diminished in soil suffering from enhanced biodegradation of MITC.     

A Granulometry-Based Selection Methodology for Separation of Traffic-Generated Particles in Urban Highway Snowmelt Runoff

Traffic activities generate a wide gradation of anthropogenic particulate matter that is entrained in highway snow and snowmelt. Granulometric-based analyses of this particulate mattercan provide guidance for selection and design for snowmelt solid/liquid separation processes. This study presents a granulometry-based analysis of snow melt particles from 10 highway shoulder sites in urban Cincinnati (State of Ohio, U.S.A.) generated from a 46 cm, 48 hr snowfall with a highwayshoulder residence time of 102 hr. Each site was exposed totraffic and maintenance activities (plowing and de-icing saltsonly). Despite variations in gradations and particle indices, measured l _nv-N _t (number-volume mean size-particle counts) values for all sites were closely modeled using a two-parameter power law model. The model exponent, β, ranged from 2.22 to 2.64 indicating that a significant fractionof surface area is associated with the coarser gradation of particles. Modeled results support previous experimental data indicating the predominance of surface area and heavy metal mass is associatedwith the coarser fraction of particles. Results indicated a statistically significant difference in densities for coarse (2.86 gm cm^-3) and fine particles (2.75 gm cm^-3) (P < 10^-11).A methodology is presented in the form of a process selection diagram to evaluate mechanisms of particle separation. It was determined that sedimentation could remove 90% of particles, bymass, within 2 hr for a typical roadway drainage design. The influence of particle specific gravity on sedimentation efficiency is illustrated for a range of specific gravities from 1.1 to 4.0. Although the very high concentrations of particulate matter in highway snow melt do not make it amenableto straining or direct filtration, such processes may be feasible as a secondary treatment for snowmelt or storm water effluent discharges to receiving waters.     

Assessment of Nitrogen Leaching at ICP-Waters Sites (Europe and North America)

The International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP-Waters) is designed to assess the degree and geographical extent of acidification of surface waters. During the last 20 years, international emission reduction measures in Europe and North America have resulted in a decrease in atmospheric S-deposition of up to 50%, while N-deposition has stayed almost constant. Empirical relationships between N-deposition and stages of nitrogen saturation are used to assess the importance of nitrogen leaching at the ICP-Waters sites in Europe and North America. There is a clear coherence between high N saturation stages and high N deposition loads and more than 50% of the analysed ICP Waters sites show a high degree of nitrogen saturation, defined as stages 2 or 3 in Stoddard's classification system. Significant leaching of inorganic N also occurs at most sites with deposition greater than 10 kg/ha/yr.     

Beach Litter Sourcing in the Bristol Channel and Wales,U.K.

Principal component analysis (PCA) and cluster analysis werecarried out on beach litter found primarily along theBristol Channel, U.K., together with beaches located aroundthe Principality of Wales. Both techniques indicated threebeach survey sites as outliers, with distinctive beachlitter profiles. PCA distinguished between riverine, sewagerelated, fishing and shipping sourced items, but did notproduce a coherent grouping for beach user litter. This wasattributed to a difference in modes of transport. Beachesfrom mid and north Wales, which had small litter amounts,were not differentiated from the central grouping. Thewestern edge of the Channel was more heavily influenced byshipping and fishing inputs than was the eastern portion.Cluster analysis showed a discrete group of beaches locatedmainly on the southern side of the Bristol Channel.     

Minirhizotron quantification of soybean root growth as affected by reduced A horizon in soil

Shallow soil A horizon (topsoil) caused by soil erosion and soil movement from cultivation is known to reduce soil and crop productivity. The reduction may be related to limitation of root growth. A field study was conducted to investigate the effects of topsoil thickness on distributions of root density and growth. Soybeans [Glycine max (L.) Merr.] were grown on plots of Mexico silt loam (fine, montmorillonitic, mesic Mollic Endoaqualfs) with topsoil thicknesses of 0, 12.5, 25.0, and 37.5 cm above the Bt horizons. Root density was measured 60 and 90 days after planting using a minirhizotron video‐camera system. Root density was significantly reduced as topsoil thickness decreased from 37.5 to 0 cm. Mean density and net change of the density across profile between 30 and 60 days of growth had a linear function of topsoil thickness. The reduction and lower activity induced by shallow topsoil were attributed to detrimental properties in the Bt horizons. Root distribution pattern and rooting depth were not significantly affected by topsoil thickness. The roots appeared to be accumulated on the upper layers of the Bt horizons. Roots growing in thicker topsoil were more active than roots growing without topsoil. High soil moisture content during the growing season may mitigate the detrimental effects of shallow topsoil, inhibit root penetration, and enhance root activity.     

The Applicability of Needle Chemistry for Diagnosing Heavy Metal Toxicity to Trees

Water, Air, &; Soil Pollution - To estimate the validity of needle chemistry as a tool for diagnosing heavy metal toxicity, we collected needle samples from mature pines and young seedlings and...