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Buffalo grass and alkaline-pretreated buffalo grass samples were co-digested with cow manure separately to generate biogas in anaerobic reactors. The study considered a solid content of 20% (10% buffalo grass and 10% cow manure). The methane (CH 4) content and CH 4 yield of the distinct experiments were compared. For the untreated buffalo grass, the weighed buffalo grass was mixed with cow manure and water. For the alkaline-pretreated buffalo grass, the weighed buffalo grass was soaked in 1% sodium hydroxide for 1 day prior to being mixed with cow manure and water. The untreated and pretreated buffalo grass-manure were fed semi-continuously at the rate of 125 mL/day for five days feeding in a 5 L reactor, with 40 days hydraulic retention time. The experiments were conducted for approximately 100 days. Results were reported when the systems were in steady-state conditions. The chemical oxygen demand (COD) conversion efficiency of co-digestion of the untreated and pretreated buffalo grass-manure were 46.21 and 62.76%, respectively, and for the total volatile solids (TVS) were 68.50 and 71.80%, respectively. The CH 4 contents generated from co-digestion of the untreated and pretreated buffalo grass-manure were 48.32% and 50.36%, respectively. The CH 4 yields generated from co-digestion of the untreated and pretreated buffalo grass-manure were 328 and 385 L/kgTVS conversion, respectively. It was observed from the experiments that pretreatment of the buffalo grass prior to co-digestion provided system stability during biogas production. • Buffalo grass has high potential as a biomass source for biogas production. • Co-digestion of NaOH-pretreated buffalo grass-manure increases CH 4 yield. • CH 4 content and CH 4 yield are 50.36% and 387 L/kg TVS conversion. • COD and TVS conversion efficiency reach 62.76 and 71.80%. • System stability increases noticeably. [ABSTRACT FROM AUTHOR]

Introduction: Herbicide resistant (HR) buffalo grasses were genetically engineered to resist the non-selective herbicide, glufosinate in order to facilitate a modern, 'weeding program' which is highly effective in terms of minimizing costs and labor. The resistant trait was conferred by an insertion of the pat gene to allow for the production of the enzyme phosphinothricin acetyltransferase (PAT) to detoxify the glufosinate inhibitive effect. To date, there are only a few reports using metabolomics as well as molecular characterizations published for glufosinate-resistant crops with no reports on HR turfgrass. Therefore, for the first time, this study examines the metabolome of glufosinate-resistant buffalo grasses which not only will be useful to future growers but also the scientific community. Objective: A major aim of this present work is to characterize and evaluate the metabolic alterations which may arise from a genetic transformation of HR buffalo grasses by comprehensively using gas chromatography–mass spectrometry (GC–MS) based untargeted metabolomics. Methods: Eight-week old plants of 4 HR buffalo grasses, (93-1A, 93-2B, 93-3C and 93-5A) and 3 wild type varieties (WT 8-4A, WT 9-1B and WT 9-1B) were selected for physiological, molecular and metabolomics experiments. Plants were either sprayed with 1, 5, 10 and 15% v/v of glufosinate to evaluate the visual injuries or submerged in 5% v/v of glufosinate 3 days prior to a GC–MS based untargeted metabolomics analysis. In contrast, the control group was treated with distilled water. Leaves were extracted in 1:1 methanol:water and then analysed, using an in-house GC–MS untargeted workflow. Results: Results identified 199 metabolites with only 6 of them (cis-aconitic acid, allantoin, cellobiose, glyceric acid, maltose and octadecanoic acid) found to be statistically significant (p < 0.05) between the HR and wild type buffalo grass varieties compared to the control experiment. Among these metabolites, unusual accumulation of allantoin was prominent and was an unanticipated effect of the pat gene insertion. As expected, glufosinate treatment caused significant metabolic alterations in the sensitive wild type, with the up-regulation of several amino acids (e.g. phenylalanine and isoleucine) which was likely due to glufosinate-induced senescence. The aminoacyl-tRNA biosynthetic pathway was identified as the most significant enriched pathway as a result of glufosinate effects because a number of its intermediates were amino acids. Conclusion: HR buffalo grasses were very similar to its wild type comparator based on a comprehensive GC–MS based untargeted metabolomics and therefore, should guarantee the safe use of these HR buffalo grasses. The current metabolomics analyses not only confirmed the effects of glufosinate to up-regulate free amino acid pools in the sensitive wild type but also several alterations in sugar, sugar phosphate and organic acid metabolism have been reported. [ABSTRACT FROM AUTHOR]

The potential growth of buffalo grass (Stenotaphrum secundatum) and couch grass (Cynodon dactylon) on artificial floating islands (AFIs) and their ability to remove total nitrogen (TN) and total phosphorus (TP) from a simulated paper mill wastewater was studied. This was done to assess the potential of AFIs for removal of nutrients from aerated stabilization basins (ASBs) that had occasional growth of blue-green algae (BGA) to bloom levels. Small scale AFIs were prepared using polyethylene foam and planted with the grasses in 30 L of tested water. Trials were conducted in a plastic covered greenhouse over a three-month period where temperatures ranged from 15 to 44 °C. The results showed that both buffalo and couch grasses can adapt to planting in AFIs showing increases of 125% and 148% in wet weight, respectively. Nutrient uptake by buffalo grass and couch grass were found to be similar. Percentage uptakes of TP and TN from the synthetic water by the buffalo grass were 82% and 47%, whereas by couch grass, uptakes were 83% and 45%, respectively. [ABSTRACT FROM AUTHOR]

Lithogenic trace element (TE) patterns of distribution, fate, and behavior in soils are influenced by plants and microorganisms. Our controlled mesocosm experiments quantified how incipient weathering of mineral-bound TEs (Be, V, Sr, Ba, Cr, Co, Ni, Mo, Cu, Zn, As, Se, Ag, Cd, Sn, Sb, Tl, and Pb) varies across four porous mineral substrates (basalt, rhyolite, granite, and schist), in the presence of buffalo grass ( Bouteloua dactyloides ), associated bacteria, and arbuscular mycorrhizal fungi (AM), a common plant symbiont. Particular focus was given to the net transfer of elements between the solid and solution phases, including chemical denudation (loss of element from the rock to the solution), plant TE uptake, and total mobilization (sum of denudation loss and uptake into plant biomass). Results revealed differences in TE denudation among rocks, basalt having the highest loss and schist the lowest. TE leaching in solution was time-dependent and it was likely influenced by variations in pH and DOC that were rock- and treatment-specific. The element with the highest rock-normalized release to the solution and highest enrichment in plant biomass was Mo across all rocks. Plants decreased denudation loss compared to abiotic controls for a large number of TEs in all substrates due to plant uptake, but for some elements increase in weathering due to plant activity resulted in increased denudation. Differences in TE patterns of behavior could be related to their Goldschmidt groups. Plant uptake was controlled by TE availability in solution, as well as plant physiological requirements. Plants and associated microbiota significantly enhanced mobilization for the majority of TEs across all rocks. Mycorrhiza significantly increased above-ground plant biomass production in rhyolite and concentrations in plant tissues for a high number of TEs in basalt. TE uptake into biomass was positively correlated with percent mycorrhizal infection, particularly in basalt and rhyolite. Mycorrhizal fungi also influenced TE denudation, rock-water fractionation, and total mobilization according to the rock type. Mycorrhizal activity was associated with a significant decrease in pH and increase in DOC fluxes in schist, supporting the idea that fungi enhance production of root exudates especially in substrates that are difficult to weather. Our results highlight the importance of incipient weathering at the plant-rock interface for patterns of TE cycling. They also indicate the importance of mycorrhiza in mineral dissolution, TE denudation, plant element uptake, and biomass growth. [ABSTRACT FROM AUTHOR]

With the objective to study the control of Brachiaria decumbens and Panicum maximum by herbicide S-metolachlor as influenced by the time interval between the herbicide application the occurrence of rain and the amount of sugarcane straw on the soil, two experiments were conducted in pots under greenhouse conditions. In the first, the factors were the amount of sugarcane straw left on the soil surface (0, 3, 6, 10, or 15 ton. ha-1) and the S-metolachlor applied at doses of 0, 0.96, 1.44, 1.92, or 2.40 kg ha-1. In the second, the factors were the amount of sugarcane straw left on the soil surface (0 or 10 ton. ha-1), the interval of time elapsed between the application of S-metolachlor and simulated rain, which took place 1 day before and 0, 4, 8, 12, 16, or 20 days after the application. The herbicide doses were not affected by the amounts of straw left on the soil surface. When straw was not left on the soil surface, the control of the weeds by the herbicide was not influenced by the time interval up to 20 days after herbicide application. With 10 ton. ha-1 of straw, the control exerted by S-metolachlor was equally efficient whether it rained up to 12 days after the herbicide application. P. maximum was controlled even when the rain fell one day before the herbicide application.Com o objetivo de estudar o controle em pré-emergência de Brachiaria decumbens e Panicum maximum pelo herbicida S-metolachlor em função do intervalo de tempo entre a aplicação e a ocorrência de chuva e da quantidade de palha de cana-de-açúcar na superfície do solo, dois experimentos foram desenvolvidos em vasos mantidos em casa de vegetação. No primeiro, foram estudadas cinco quantidades de palha sobre o solo (0, 3, 6, 10 e 15 t ha-1) e cinco dosagens de S-metolachlor (0; 0,96; 1,44; 1,92 e 2,40 kg ha-1). No outro, foram avaliadas duas quantidades de palha sobre o solo (0 e 10 t ha-1) e sete intervalos de tempo entre a aplicação de S-metolachlor e a simulação de chuva (1 dia antes; logo após; 4, 8, 12, 16 e 20 dias após a aplicação). As dosagens de S-metolachlor não foram afetadas pelos níveis de palha na superfície do solo. Além disso, sem a manutenção de palha sobre o solo, o controle das plantas daninhas pelo herbicida S-metolachlor não foi influenciado pelos intervalos de tempo entre a aplicação e a simulação de chuva, até 20 dias. Com 10 t ha-1 de palha, o controle de B. decumbens e P. maximum pelo S-metolachlor não foi prejudicado quando choveu até 12 dias da sua aplicação ou um dia antes, mas, nesse caso apenas para P. maximum.

Rock colonization by plant roots and their associated microbiota is one of the major drivers of mineral weathering, nutrient cycling, soil formation and ecosystem stability. Yet the mechanisms of bio-uptake of lithogenic elements from rocks with differential nutrient availabilities and limitations are yet to be established. Here we present results from a mesocosm experiment that examined lithogenic element dissolution and uptake (P, K, Ca, Mg, Mn, Fe, Na, Ti, Al and Si) in Bouteloua dactyloides (buffalo grass) grown on four different granular porous media (basalt, rhyolite, granite and schist) comprised of primary mineral assemblages as influenced by arbuscular mycorrhiza (AM; Rhizophagus irregularis). Our results demonstrated that nutrient mobilization (chemical denudation + plant uptake) in such oligotrophic systems is governed by nutrient supply in the parent material, nutrient availability in pore water solution, and plant physiology. Overall, total major lithogenic element mobilization in planted columns (with and without AM) exceeded abiotic controls in all substrates. Differences in total mobilization among substrates occurred as follows: Fe, Na, Ti and Al reached high values in planted treatments in basalt, P and Mn in rhyolite, Ca and K in granite and K in schist, suggesting enhanced dissolution of primary minerals in the presence of plants. Element biomass enrichment of Mn, Fe, Ti and Al appeared to be higher in basalt than the rest of the substrates; however, high Al availability limited Ca and Mg uptake and plant growth in this rock media. Presence of mycorrhiza enhanced shoot biomass in rhyolite due to increased P uptake, and increased concentrations and total uptake of lithogenic elements in plants in all rocks but granite. As expected, AM significantly increased plant root concentrations of P, K, Ca, Mn, Fe, Ti, Al in basalt, and Mn shoot concentrations in rhyolite, as well as root total uptake of K, Ca, Mg, Mn, Fe, Na, Ti, Al and Si in basalt. At the same time, AM decreased Ca, Ti and Al concentrations in shoots grown in rhyolite, a possible protection mechanism against Al toxicity. The importance of AM in nutrient uptake is also reinforced by positive correlations between AM infection rate and P, Ca and Mn total uptake across all substrates. Moreover, total mobilization of Ca, Mg and Mn in rhyolite, was significantly higher in the AM versus non-AM treatment, contrary to K, Ca, Mg, Na and Si in schist. Our work demonstrates how mineral weathering and associated nutrient release is promoted by plant processes, further enhanced by plant associated with symbiotic AM, and yet more pronounced in basalt and rhyolite compared to granite and schist. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pesticides are developed with carriers to improve their physicochemical properties and, accordingly, the bioefficacy of the applied formulation. For foliar-applied herbicide, generally less than 0.1% of the active ingredient reaching the target site could reduce pesticide performance. Recently, a carrier of nanoemulsion consisting of oil, surfactant and water, with a particle size of less than 200 nm, has been shown to enhance drug permeability for skin penetration in pharmaceutical delivery systems. In the present work, the aim was to formulate a water-soluble herbicide, glyphosate isopropylamine (IPA), using a green nanoemulsion system for a biological activity study against the weeds creeping foxglove, slender button weed and buffalo grass. RESULTS: The nanoemulsion formulations displayed a significantly lower spray deposition on creeping foxglove (2.9-3.5 ng cm−2), slender button weed (2.6-2.9 ng cm−2) and buffalo grass (1.8-2.4 ng cm−2) than Roundup® (3.7-5.1 ng cm−2). The visible injury rates of weeds treated with the nanoemulsion formulations were statistically equivalent to those relating to Roundup® at 14 days after treatment, with a control range of 86.67-96.67%. CONCLUSION: It was hypothesised that the significant difference in spray deposition with equal injury rates can be attributed to enhanced bioactivity of the nanoemulsion formulations. This initial discovery could be the platform for developing better penetration of agrochemical formulations in the future. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

With the objective to study the control of Brachiaria decumbens and Panicum maximum by herbicide S-metolachlor as influenced by the time interval between the herbicide application the occurrence of rain and the amount of sugarcane straw on the soil, two experiments were conducted in pots under greenhouse conditions. In the first, the factors were the amount of sugarcane straw left on the soil surface (0, 3, 6, 10, or 15 ton. ha-1) and the S-metolachlor applied at doses of 0, 0.96, 1.44, 1.92, or 2.40 kg ha-1. In the second, the factors were the amount of sugarcane straw left on the soil surface (0 or 10 ton. ha-1), the interval of time elapsed between the application of S-metolachlor and simulated rain, which took place 1 day before and 0, 4, 8, 12, 16, or 20 days after the application. The herbicide doses were not affected by the amounts of straw left on the soil surface. When straw was not left on the soil surface, the control of the weeds by the herbicide was not influenced by the time interval up to 20 days after herbicide application. With 10 ton. ha-1 of straw, the control exerted by S-metolachlor was equally efficient whether it rained up to 12 days after the herbicide application. P. maximum was controlled even when the rain fell one day before the herbicide application. [ABSTRACT FROM AUTHOR]

Abstract: A greenhouse experiment was conducted to evaluate the competitive abilities of Schizachyrium scoparium (little bluestem) and Buchloe dactyloides (buffalo grass) in low and high nutrient soil. These species have overlapping ranges and co-occur in semi-arid North American grasslands. Both species showed increases of approximately 2g plant−1 in aboveground dry mass when soil nutrients were added. Aboveground dry mass of S. scoparium was slightly higher in mixture than in monoculture in low nutrient soil; however, in high nutrient soil, aboveground dry mass in mixture was significantly less than in monoculture. Buchloe dactyloides aboveground dry mass was the same in mixture and monoculture in low nutrient soil; in high nutrient soil, aboveground dry mass was significantly higher in mixture than monoculture. The competitive abilities of these species in shallow soils are dependent upon soil resource levels. At low soil resources, competitive intensity is not great and the two species appear to be equal competitors. At high soil resources, competitive intensity is greater and B. dactyloides reduced the growth of S. scoparium in mixtures. Differences in competitive abilities suggest that during the establishment phase, B. dactyloides would dominate in shallow-high nutrient soils and that coexistence would occur in low nutrient soils. [Copyright &y& Elsevier]

Thirty-six mesocosms, each containing a two-species community of Trifolium repens (C3 legume) and Stenotaphrum secundatum (C4 grass), were grown in sand with three nutrient regimes, zero N low P, zero N high P and supplied N high P, under ambient (aCO2) and twice ambient CO2 (eCO2) for 15 months in two greenhouses. Aboveground annual production in the P limited mesocosms did not respond to eCO2 and was reduced by 50% relative to mesocosms with an adequate P supply, where dry-matter production was increased by 12–24% under eCO2. The stimulation of production by eCO2 occurred throughout the year despite a clear seasonality in growth. There was no effect of eCO2 on leaf area index (LAI), which was larger under high P than low P. Live root mass at the end of the experiment was higher under eCO2 in all nutrient treatments, but the response of total belowground C (root+soil) to eCO2 depended on P treatment. Under limiting P, belowground C was not significantly changed by eCO2 (2–2.3 t belowground C ha−1). Under high P supply, both root and soil C pools increased under eCO2. Under aCO2, low P supply increased belowground C by 0.7–1 t C ha−1 above that added by the high P treatment. P is commonly limiting in Australian ecosystems and the majority of ecosystem N input is provided by biological N fixation. Consequently, the response of legumes to eCO2 is of particular importance. These results demonstrate that at low P availability, there is likely to be only a limited response of biomass production by T. repens to eCO2, which in turn may constrain any ecosystem response. [ABSTRACT FROM AUTHOR]