A comparison of canopy evapotranspiration for maize and two perennial grasses identified as potential bioenergy crops

In the Midwestern US, perennial rhizomatous grasses (PRGs) are considered one of the most promising vegetation types to be used as a cellulosic feedstock for renewable energy production. The potential widespread use of biomass crops for renewable energy production has sparked numerous environmental concerns, including the impacts of land‐use change on the hydrologic cycle. We predicted that total seasonal evapotranspiration (ET) would be higher for PRGs relative to maize resulting from higher leaf area and a prolonged growing season. We further predicted that, compared with maize, higher aboveground biomass associated with PRGs would offset the higher ET and increase water‐use efficiency (WUE) in the context of biomass harvests for liquid biofuel production. To test these predictions, ET was estimated during the 2007 growing season for replicated plots of Miscanthus×giganteus (miscanthus), Panicum virgatum (switchgrass), and Zea mays (maize) using a residual energy balance approach. The combination of a 25% higher mean latent heat flux (λET) and a longer growing season resulted in miscanthus having ca. 55% higher cumulative ET over the growing season compared with maize. Cumulative ET for switchgrass was also higher than maize despite similar seasonal‐mean λET. Based on total harvested aboveground biomass, WUE was ca. 50% higher for maize relative to miscanthus; however, when WUE calculated from only maize grain biomass was compared with WUE calculated from miscanthus harvested aboveground biomass, this difference disappeared. Although WUE between maize and miscanthus differed postsenescence, there were no differences in incremental WUE throughout the growing season. Despite initial predictions, aboveground biomass for switchgrass was less than maize; thus WUE was substantially lower for switchgrass than for either maize scenario. These results indicate that changes in ET due to large‐scale implementation of PRGs in the Midwestern US would likely influence local and regional hydrologic cycles differently than traditional row crops.     

Bacterial endophytes from arid land plants regulate endogenous hormone content and promote growth in crop plants: an example of Sphingomonas sp. and Serratia marcescens

The objective of the present study was to determine the potential plant growth-promoting action of bacterial endophytes isolated from arid land-dwelling plants under normal conditions. Overall, five bacterial endophytes LK11 (Sphingomonas sp. LK11), TP5 (Bacillus subtilis), MPB5.3 (B. subtilis subsp. Subtilis), S9 (B. subtilis subsp. Subtilis), and TP1 (Serratia marcescens) were evaluated based on morphological characteristics after isolation and purification. Phytohormonal analysis of these endophytes predicted indole acetic acid (IAA) production 12.31?±?0.45?, 6.8?±?0.59, and 10.5?±?1.02?μM/mL in the culture broths of LK11, MPB5.3, and TP1, respectively. Under controlled greenhouse conditions, these endophytes were inoculated into soybean, and their growth-promoting characteristics were compared with those of non-phytohormone-producing endophytes. In terms of plant growth promotion, among IAA-producing endophytes, LK11 and TP1 greatly improved physiological characteristics such as shoot/root length, fresh/dry weight, and chlorophyll contents. However, the non-phytohormone-producing endophytes TP5 and S9 did not show a growth-promoting effect. Based on these results, plants inoculated with LK11 and TP1 along with a control were subjected to endogenous hormonal analysis and showed a significant increase in abscisic acid (457.30–398.55 vs. 205.93 ng/g D.W.) and a decrease in jasmonic acid content (50.07–85.07 vs. 93.90 ng/g D.W.), respectively. Total gibberellin content was found to significantly increase in endophyte-inoculated plants (155.43–146.94?ng/g D.W.) as compared to that in controls (113.76 ng/g D.W.). In summary, bacterial endophytes might be used to enhance crop plant physiological characteristics isolated from arid land-inhabiting plants under normal conditions.     

Effect of ante- and postmortem hide clipping on the microbiological quality and safety and ultimate pH value of beef carcasses in an EC-approved abattoir

Aims:  Effect of ante- and postmortem hide clipping on the microbiological quality of beef carcasses. Methods and Results:  Bovine carcasses (362) were tested for indicator micro-organisms and the presence of pathogens. Prior to slaughter, hide cleanliness of each animal was categorized on a scale of 1–5 (clean to dirty). Lowest mean aerobic colony counts (ACC) (log₁₀ 3·0 CFU cm⁻²) came from carcasses where clipping had been performed in lairage, antemortem. ACC from animals clipped online (log₁₀ 3·2 CFU cm⁻²) were significantly higher (P < 0·05) than those clipped in lairage, but comparable to those carcasses from Category 1 and 2 animals. There were no significant differences in the detection of pathogens from any of the carcass groups. Ultimate pH values for carcasses from Category 3 and 4 animals showed clipping animals in lairage, as opposed to online, resulted in a small, but significant increase (P < 0·05) in pH value (mean pH 5·66 and 5·59, respectively). Conclusions:  Hide clipping does not adversely affect microbiological quality of carcasses, although higher ultimate pH values indicate increases in antemortem stress. Significance and Impact of the Study:  Hide clipping carcasses both ante- and postmortem appears to be an effective intervention to minimize transfer of hide microflora to carcasses during slaughtering operations. Online clipping offers advantages for animal welfare and improves safety for operatives.     

Lactic acid production from agriculture residues

Various agriculture feedstock residues were evaluated for lactic acid production by simultaneous saccharification and fermentation (SSF) using Lactobacillus delbrueckii and Lactobacillus plantarum, without any additional nutrients. Lactic acid production was higher in alfalfa fiber and soya fiber compared to corncob (soft) and wheat straw. In Lactobacillus plantarum, the amount of lactic acid obtained from alfalfa fiber and soya fiber was 46 and 44 g/100 g fiber, respectively. However, in Lactobacillus delbrueckii, the lactic acid production in soya fiber was 44 g/100 g fiber and that of alfalfa was 32 g/100 g fiber. Small amounts of acetic acid were also produced from SSF of agricultural feedstocks residues. During SSF of alfalfa fiber, lactic acid production in both L. delbrueckii and L. plantarum was enhanced by adding pectinases and cellulases. Lactic acid production from alfalfa fiber did not change with increasing O₂ transfer rates in the fermentation medium, whereas acetic acid production in both Lactobacillus cultures increased with increasing O₂ transfer rates.     

Influence of soil type, moisture content and biosolids application on the fate of Escherichia coli in agricultural soil under controlled laboratory conditions

AIMS: To determine the fate of the enteric indicator organism, Escherichia coli, in sewage sludge (biosolids)-amended agricultural soil in relation to soil type and moisture status under controlled conditions. METHODS AND RESULTS: We enumerated Escherichia coli in soil by membrane filtration and most probable number techniques. The background concentration of E. coli was higher in sandy loam than in silty clay soil. E. coli numbers increased in soil following addition of dewatered, mesophilic anaerobically digested sludge. Escherichia coli declined to a small extent with time in both moist and air-dried unamended control soils, although decay was only highly significant (P < 0.001) in moist sandy loam (T(90) = 100 days). Removal rates were high in sludge-treated moist soil (T(90) = 20 days), but were significantly reduced in amended air-dried soil. CONCLUSIONS: Slow removal of E. coli in air-dried soil as against their rapid decay in moist soil after sludge application indicated that the soil biota are involved in pathogen reduction processes in sludge-amended soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Soil ecological mechanisms are implicated as having a critical role in the fate of enteric organisms introduced into temperate agricultural soil in sewage sludge.     

Using euhalophytes to understand salt tolerance and to develop saline agriculture: Suaeda salsa as a promising model

Background As important components in saline agriculture, halophytes can help to provide food for a growing world population. In addition to being potential crops in their own right, halophytes are also potential sources of salt-resistance genes that might help plant breeders and molecular biologists increase the salt tolerance of conventional crop plants. One especially promising halophyte is Suaeda salsa, a euhalophytic herb that occurs both on inland saline soils and in the intertidal zone. The species produces dimorphic seeds: black seeds are sensitive to salinity and remain dormant in light under high salt concentrations, while brown seeds can germinate under high salinity (e.g. 600 mm NaCl) regardless of light. Consequently, the species is useful for studying the mechanisms by which dimorphic seeds are adapted to saline environments. S. salsa has succulent leaves and is highly salt tolerant (e.g. its optimal NaCl concentration for growth is 200 mm). A series of S. salsa genes related to salt tolerance have been cloned and their functions tested: these include SsNHX1, SsHKT1, SsAPX, SsCAT1, SsP5CS and SsBADH. The species is economically important because its fresh branches have high value as a vegetable, and its seed oil is edible and rich in unsaturated fatty acids. Because it can remove salts and heavy metals from saline soils, S. salsa can also be used in the restoration of salinized or contaminated saline land.Scope Because of its economic and ecological value in saline agriculture, S. salsa is one of the most important halophytes in China. In this review, the value of S. salsa as a source of food, medicine and forage is discussed. Its uses in the restoration of salinized or contaminated land and as a source of salt-resistance genes are also considered.