Practice to avoid contamination of drainflow and runoff from slurry spreading in spring

Abstract. Use of either three or six occasions to spread similar total amounts of slurry was investigated over the late winter/early spring period in two years, on plots with underdrainage. Slurry was spread on four 7 m by 25 m plots which were instrumented to allow collection of drainflow and runoff. The 'mobile water' pore space allowed transport of a small proportion of applied slurry through the 0.75 m soil profile. Evidence of a polluted 'mobile water' pulse occurred after periods of up to 48 hours following spreading, suggesting subsurface rather than overland flow. Timing of the pulse depended on whether subsequent rainfall accelerated the flow The contaminated flow persisted for 6–12 hours. The worst contamination of 39 mg/l NH₄⁺ -N occurred under 'bypass flow' conditions, when 52 mm of rain fell during the 48 hours after a 5.2 mm application. Two contributory factors appeared important. The first was the long duration of the high intensity storm and the second was an extended period of severe frost believed to have created fissures associated with frost heave. Making several applications of slurry in amounts less than 35 m³/ha is preferable to fewer larger applications during spring, for cereals on medium to heavy soils. This recognises the likelihood of there being underdrainage on arable land and the optimal use of well-drained, partially frozen ground to avoid compaction by slurry tankers.     

Distribution of phosphorus in soil aggregate fractions and its significance with regard to phosphorus transport in agricultural runoff

Surface runoff is the major way of P transport from agricultural land to surface waters. To assess the potential of P loss in runoff in relation to soil P status, the chemical nature and distribution of soil P in different size classes of water-stable aggregates were quantified for two distinctive soil types. For both soils unfertilized areas under pasture and well-fertilized arable soils were sampled. The content of total P, organic P and microbial biomass P (P_mic) decreased in the aggregate size order <0.1, 1–2, and 0.1–1.0 mm respectively. In contrast available P (extracted by Bray I reagent) was lowest in the <0.1 mm aggregate size. Cultivation decreased the percentage of 1–2 mm aggregates but increased that of the <0.1 mm aggregates. Fertilization increased markedly both total P and organic P in the <0.1 mm fraction of arable soils compared to the corresponding samples from unfertilized grassland soils. During aggregate separation, most of P loss was in the form of particulate P and less than 1% in solution. More organic P and P_mic were lost from the grassland soils than from the arable soils.     

A Novel Modified Endosperm Texture in a Mutant High‐Protein Digestibility/High‐Lysine Grain Sorghum (Sorghum bicolor (L.) Moench)

Development of high‐protein digestibility (HPD)/high‐lysine (hl) sorghum mutant germplasm with good grain quality (i.e., hard endosperm texture) has been a major research objective at Purdue University. Progress toward achieving this objective, however, has been slow due to challenges posed by a combination of genetic and environmental factors. In this article, we report on the identification of a sorghum grain phenotype with a unique modified endosperm texture that has near‐normal hardness and possesses superior nutritional quality traits of high digestibility and enhanced lysine content. These modified endosperm lines were identified among F₆ families developed from crosses between hard endosperm, normal nutritional quality sorghum lines, and improved HPD/hl sorghum mutant P721Q‐derived lines. A novel vitreous endosperm formation originated in the central portion of the kernel endosperm with opaque portions appearing both centrally and peripherally surrounding the vitreous portion. Kernels exhibiting modification showed a range of vitreous content from a slight interior section to one that filled out to the kernel periphery. Microstructure of the vitreous endosperm fraction was dramatically different from that of vitreous normal kernels in sorghum and in other cereals, in that polygonal starch granules were densely packed but without the typically associated continuous protein matrix. We speculate that, due to the lack of protein matrix, such vitreous endosperm may have more available starch for animal nutrition, and possibly have improved wet‐milling and dry‐grind ethanol processing properties. The new modified endosperm selections produce a range that approaches the density of the vitreous parent, and have lysine content and protein digestibility comparable to the HPD/hl opaque mutant parent.     

Identification and characterization of complex bioactive oligosaccharides in white and red wine by a combination of mass spectrometry and gas chromatography

Over forty-five complex free oligosaccharides (of which several are novel) have been isolated and chemically characterized by gas chromatography and high resolution and high mass accuracy matrix-assisted laser desorption/ionization mass spectrometry (MALDI-FTICR MS) in red and white wines, Grignolino and Chardonnay, respectively. Oligosaccharides with a degree of polymerization between 3 and 14 were separated from simple monosaccharides and disaccharides by solid-phase extraction. The concentrations of free oligosaccharides were over 100 mg/L in both red and white wines. The free oligosaccharides-characterized for the first time in the present study-include hexose-oligosaccharides, xyloglucans, and arabinogalactans and may be the natural byproduct of the degradation of cell wall polysaccharides. The coupled gas chromatography and accurate mass spectrometry approach revealed an effective method to characterize and quantify complex functional oligosaccharides in both red and white wine.     

The fate of Amazonian forest fragments: A 32-year investigation

We synthesize findings to date from the world’s largest and longest-running experimental study of habitat fragmentation, located in central Amazonia. Over the past 32 years, Amazonian forest fragments ranging from 1 to 100 ha have experienced a wide array of ecological changes. Edge effects have been a dominant driver of fragment dynamics, strongly affecting forest microclimate, tree mortality, carbon storage, fauna, and other aspects of fragment ecology. However, edge-effect intensity varies markedly in space and time, and is influenced by factors such as edge age, the number of nearby edges, and the adjoining matrix of modified vegetation surrounding fragments. In our study area, the matrix has changed markedly over the course of the study (evolving from large cattle pastures to mosaics of abandoned pasture and regrowth forest) and this in turn has strongly influenced fragment dynamics and faunal persistence. Rare weather events, especially windstorms and droughts, have further altered fragment ecology. In general, populations and communities of species in fragments are hyperdynamic relative to nearby intact forest. Some edge and fragment-isolation effects have declined with a partial recovery of secondary forests around fragments, but other changes, such as altered patterns of tree recruitment, are ongoing. Fragments are highly sensitive to external vicissitudes, and even small changes in local land-management practices may drive fragmented ecosystems in markedly different directions. The effects of fragmentation are likely to interact synergistically with other anthropogenic threats such as logging, hunting, and especially fire, creating an even greater peril for the Amazonian biota.     

Comparison of the α-amylase inhibitor-1 from common bean (Phaseolus vulgaris) varieties and transgenic expression in other legumes--post-translational modifications and immunogenicity

The seeds of peas (Pisum sativum) and chickpeas (Cicer arietinum) expressing a gene for α-amylase inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are protected from damage by old world bruchids (pea and cowpea weevils). Here, we used electrospray ionization time-of-flight mass spectrometry to compare the post-translational modifications of αAI from transgenic sources with the processed forms of the protein from several bean varieties. All sources showed microheterogeneity with differences in the relative abundance of particular variants due to differences in the frequency of addition of glycans, variable processing of glycans, and differences of C-terminal exopeptidase activity. The structural variation among the transgenics was generally within the range of the bean varieties. Previously, mice showed allergic reactions following ingestion of transgenic pea αAI but not bean αAI. Here, only minor differences were observed following intraperitoneal sensitization. Both of the transgenic pea and bean forms of αAI elicited Th1 and Th2 antibody isotype responses, suggesting that both proteins are immunogenic and could potentially be allergenic.     

Sustainable Management of Landfill Leachate by Irrigation

Leachate from domestic landfills is a significant environmentalhazard. In the urban environment, irrigation of recreational turf and parkland with nitrogen-rich landfill leachate providesboth low-cost treatment that minimises pollution of surroundingwaters and a valuable water resource. Of particular interest isthe capacity of the turf-soil system to ameliorate the ammonium-rich leachate. To address this issue, a two-year field trial was completed at the Newington Landfill irrigating with saline,ammonium-rich leachate. The field trial suggested that in situ bioremediation is sustainable provided that management strategies such as dilution of leachate to reduce solution electrical conductivity to 3.6 dS m^-1 are adopted. Furthermore, pollution due to leaching of nitrogen can be minimised by managing the soil to enhance in situ denitrification of applied nitrogen. The management regimes adopted during the Newington field trial enabled nitrogen application rates in excess of 1400 kg NH₄ ⁺ha^-1 yr^-1. However, the capacity of the system to ameliorate the leachate appears limited by soil salinity and sodicity rather than the control of nitrogen leaching by denitrification,suggesting that rates of up to 3500 kg NH₄ ⁺ha^-1 yr^-1 may be viable if the salinity hazard can be effectively managed.     

Identification of fonofos metabolites in Latuca sativa, Beta vulgaris, and Triticum aestivum by packed capillary flow fast atom bombardment tandem mass spectrometry

The metabolism of fonofos, a thiophosphonate insecticide, was investigated in mature lettuce (Latuca sativa), beet (Beta vulgaris), and wheat (Triticum aestivum). Six new metabolites were identified by LC-MS and LC-MS-MS analysis using fast atom bombardment (FAB) and packed capillary LC columns with application of the on-column focusing technique. These methods provided the sensitivity required to identify unknown metabolites that were present in the mature plants at only 20-230 ppb. Structural elucidation was facilitated by use of fonofos labeled with both carbon-14 and carbon-13 in the phenyl ring. In all three plants fonofos was converted to a glucose conjugate of thiophenoxylactic acid. Oxidation of the glucose conjugate gave isomeric sulfoxides in all species examined. Thiophenoxylactic acid was found esterified to malonic acid in lettuce. In beets, S-phenylcysteine was found as its malonic acid amide. A second metabolite unique to beets was N-(malonyl)-[2[(ethoxyethylphosphinothionyl)oxy]phenyl]cysteine. This novel structure was confirmed by synthesis.     

Infrared heater arrays for warming field plots scaled up to 5-m diameter

As Earth continues to warm globally, there is a need to conduct ecosystem plot warming experiments under conditions as representative of open fields in the future as possible. One promising approach is to use hexagonal arrays of infrared heaters such as described by [Kimball, B.A., Conley, M.M., Wang, S., Lin, X., Luo, C., Morgan, J., Smith, D., 2008. Infrared heater arrays for warming ecosystem field plots. Global Change Biology 14, 309–320]. However, their plots were only 3 m in diameter (7.1 m²), which limits the stature of vegetation to shorter than about 1 m and also limits the amount of plant material that can destructively harvested. Therefore, we tested a larger hexagonal 5-m diameter array of infrared heaters, which provided a near tripling of useable area (19.6 m²). The number of heaters was tripled from 6 to 18, and their height above the vegetative (wheat) canopy was scaled with the diameter (0.4 times diameter = 2.0 m). Distributions of down-going thermal radiation and of the resultant warming of the vegetation were quite uniform across the plot. Moreover, the same equation previously determined from 3-m diameter plots to describe the thermal radiation efficiency as a function of wind speed was still applicable. Thus, no problems were encountered in tripling the area of the infrared heater-warmed plots.