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In the Pampas, public concern has strongly risen because of the intensive use of glyphosate for weed control and fallow associated with biotech crops. The present study was aimed to evaluate the occurrence and concentration of the herbicide and its main metabolite (AMPA) in soil and other environmental compartments of the mentioned agroecosystem, including groundwater, in relation to real-world agricultural management practices in the region. Occurrence was almost ubiquitous in solid matrices (83–100%) with maximum concentrations among the higher reported in the world (soil: 8105 and 38939; sediment: 3294 and 7219; suspended particulate matter (SPM): 584 and 475 μg/kg of glyphosate and AMPA). Lower detection frequency was observed in surface water (27–55%) with maximum concentrations in whole water of 1.80 and 1.90 μg/L of glyphosate and AMPA, indicating that SPM analysis would be more sensitive for detection in the aquatic ecosystem. No detectable concentrations of glyphosate or AMPA were observed in groundwater. Glyphosate soil concentrations were better correlated with the total cumulative dose and total number of applications than the last spraying event dose, and an increment of 1 mg glyphosate/kg soil every 5 spraying events was estimated. Findings allow to infer that, under current practices, application rates are higher than dissipation rates. Hence, glyphosate and AMPA should be considered “pseudo-persistent” pollutants and a revisions of management procedures, monitoring programs, and ecological risk for soil and sediments should be also recommended. [ABSTRACT FROM AUTHOR]

The impacts of invasive plant control on native animals are rarely evaluated. Using data from an eight-year study in southeastern Australia, we quantified the effects on native bird, mammal, and reptile species of (1) the abundance of the invasive Bitou Bush, Chrysanthemoides monilifera ssp. rotundata, and (2) a Bitou Bush control program, which involved repeated herbicide spraying interspersed with prescribed burning. We found that overall species richness of birds, mammals, and reptiles and the majority of individual vertebrate species were unresponsive to Bitou Bush cover and the number of plants. Two species including the nationally endangered Eastern Bristlebird (Dasyurus brachypterus) responded positively to measures of native vegetation cover following the control of Bitou Bush. Analyses of the effects of different components of the treatment protocol employed to control Bitou Bush revealed (1) no negative effects of spraying on vertebrate species richness; (2) negative effects of spraying on only one individual species (Scarlet Honeyeater); and (3) lower bird species richness but higher reptile species richness after fire. The occupancy of most individual vertebrates species was unaffected by burning; four species responded negatively and one positively to fire. Our study indicated that actions to remove Bitou Bush generally have few negative impacts on native vertebrates. We therefore suggest that controlling this highly invasive exotic plant species has only very limited negative impacts on vertebrate biota. [ABSTRACT FROM AUTHOR]

The USDA NRCS Aberdeen Plant Materials Center (PMC) produces certified early generation seed of hoary tansyaster (Machaeranthera canescens (Pursh) A. Gray [Asteraceae]), a late summer and fall blooming forb native to the Intermountain West region. Hoary tansyaster is an excellent forb candidate for restoration efforts in arid to semiarid sites. It is relatively easy to manage in a seed production system, establishes quickly in a rangeland situation, and provides blooms in late summer during the establishment year. Propagation methodologies including establishment, weed control, harvest, and seed processing are herein discussed. We have grown seed production fields of hoary tansyaster in 2 different field systems, one using weed barrier fabric and the other in open drill-seeded fields. Seed can be collected by hand, combine, Flail-Vac, or vacuum-type harvester and can be processed with brush machine and air-screen type cleaning equipment. Seed yields at Aberdeen, Idaho, range between 2 and 8 kg pure live seed (PLS)/ha (2-7 lb/ac). [ABSTRACT FROM AUTHOR]

Soybean shows special sensitivity to weeding while in the early growth stages until the land is covered, but also in the mature stages after the leaves begin to fall. Once invaded by weeds, especially in the first phase of growth, the culture is no longer recovering even if later, weeds are controlled. The purpose of presented paper is to identify an integrated weed control system for the soybean crop, starting from: (i) requirements of the soybean crop towards environmental and technological factors so that it can effectively compete with weeds; (ii) reporting the weed control strategy to new climatic conditions through specific measures of adaptation; (iii) strategies research of chemical complementary herbicides regarding their combat range and time of application. In order to maintain soybean cultures clean of weeds, it is necessary, in general, to apply two chemical treatments, the first ppi/pre-emergent spraying for some annual dicotyledonous and monocotyledonous weeds and the 2nd post-emergence treatment for dicotyledonous weeds. If on vegetation exists infestations both with annual or perennial monocotyledonous weeds, good results are obtained by associating two complementary herbicides, which combat both monocotyledonous and dicotyledonous weeds. The lowest degree of weed (7.5 weed/m2) was determined with the combination: Frontier Forte & Surdone & Pulsar & Stratos Ultra. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated how nitrogen (N) nutrition and key physiological processes varied under changed water and nitrogen competition resulting from different weed control and fertilisation treatments in a 2-year-old F hybrid ( Pinus elliottii Engelm var. elliottii × P. caribaea var. hondurensis Barr. ex Golf.) plantation on a grey podzolic soil type, in Southeast Queensland. Materials and methods: The study integrated a range of measures including growth variables (diameter at ground level (DGL), diameter at breast height (DBH) and height (H)), foliar variables (including foliar N concentration, foliar δC and δN) and physiological variables (including photosynthesis (A), stomatal conductance (g), transpiration ( E), intrinsic water use efficiency (WUE) ( A/g) and xylem pressure potential (Ψ)) to better understand the mechanisms influencing growth under different weed control and fertilisation treatments. Five levels of weed control were applied: standard (routine), luxury, intermediate, mechanical and nil weed control, all with routine fertilisation plus an additional treatment, routine weed control and luxury fertilisation. Relative weed cover was assessed at 0.8, 1.1 and 1.6 years after plantation establishment to monitor the effectiveness of weed control treatments. Soil investigation included soil ammonium (NH-N), nitrate (NO-N), potentially mineralizable N (PMN), gravimetric soil moisture content (MC), hot water extractable organic carbon (HWETC), hot water extractable total N (HWETN), total C, total N, stable C isotope composition (δC), stable N isotope composition (δN), total P and extractable K. Results and discussion: There were significant relationships between foliar N concentrations and relative weed cover and between tree growth and foliar N concentration or foliar δN, but initial site preparation practices also increased soil N transformations in the planting rows reducing the observable effects of weed control on foliar δN. A positive relationship between foliar N concentration and foliar δC or photosynthesis indicated that increased N availability to trees positively influenced non-stomatal limitations to photosynthesis. However, trees with increased foliar N concentrations and photosynthesis were negatively related to xylem pressure potential in the afternoons which enhanced stomatal limitations to photosynthesis and WUE. Conclusions: Luxury and intermediate weed control and luxury fertilisation positively influenced growth at early establishment by reducing the competition for water and N resources. This influenced fundamental key physiological processes such as the relationships between foliar N concentration, A, E, g and Ψ. Results also confirmed that time from cultivation is an important factor influencing the effectiveness of using foliar δN as an indicator of soil N transformations. [ABSTRACT FROM AUTHOR]

In Romania, the value added tax as an indirect tax appeared in 1993 along with the transition to the market economy, replacing the turnover tax, used between 1989 and 1993, and the single tax, used before 1989. The value added tax is a general neutral single indirect tax which is to be paid divided into fractions in all the stages of the business cycle, in order to be tolerated by the final consumer. According to the Fiscal Code, the scope of the VAT includes the operations that meet at the same time the following requirements: the operations that constitute a supply of goods or a delivery of services within the scope of the tax, made by payment; the place of supplying goods or delivering services is thought to be in Romania; the supply of goods or the delivery of services are made by a taxable person; the goods supply or the services delivery result from one of the economic activities under the law. At present, there are three VAT rates in Romania: the standard rate of 24%, which is applied to the tax basis for the taxable transactions that are not tax-free or for the transactions which are not liable to reduced rates; the reduced rate of 9%, which is applied to the tax basis for the following services: the bakery, the access to castles, the museums, the memorials, the monuments, the zoos, the delivery of textbooks, books, newspapers and magazines, the delivery of human and veterinary drugs, etc; the reduced rate of 5%, applied to the tax basis for the delivery of social housing as part of the social policy, including the ground on which they are built. [ABSTRACT FROM AUTHOR]

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A 10-year science-management partnership has focussed on three key issues within Booderee National Park in eastern Australia: the impacts of fire on native biota, the response of vertebrates to feral animal control and the control of Bitou Bush. What has been achieved to date and what are the partnership's key ingredients? [ABSTRACT FROM AUTHOR]

The article presents a research study which examines the role of microbial activities and soil properties on the interrelated degradation and sorption processes of mesotrione in four soils by measuring plant-available water (PAW). The quick degradation in the PAW became rate restricted by sorption as more molecules that are available were depleted in the soil pore water, leading in a more slowed overall procedure for the total soil-water system. A coupled kinetics model measured with the data from the technique of laboratory centrifugation offered an effective approach to examine the interrelated processes of degradation and sorption in realistic soil moisture conditions.

Summary 1. Invasive plants destroy the structure and function of many ecosystems but removal is expensive, so the likelihood of success should be assessed before a major control programme commences. Trial clearings can clarify how best to design and perform broad-scale clearing programmes. Such trials need to consider the range of conditions that might affect the outcome of control operations, not least the duration of invasion before clearing commences, a parameter that has rarely been considered previously. 2. The recovery of plant communities was monitored over 6 years in a Portuguese coastal dune system after the removal of invasive Acacia longifolia plants, together with the underlying litter in half of the cleared areas but not in the remainder. Areas that had been invaded for >20 years (long-invaded) as opposed to <7 years (recently invaded) were compared. 3. After the removal of A. longifolia, recently invaded areas had more exotic plant species but also higher native species richness, plant cover, initial diversity and species turnover rates than long-invaded areas. Generalist native species were initially very abundant in cleared areas but progressively gave way to species more typical of dunes. Six years after clearing, many species that usually occur on dunes were still missing. Therophytes were the most abundant life form immediately after clearing, but nanophanerophytes, chamaephytes and A. longifolia increased with time. Seedlings of A. longifolia were most abundant in long-invaded areas, but litter removal along with plants promoted increased plant species richness and cover and decreased susceptibility to reinvasion. 4. Synthesis and applications. A number of variables can affect the outcome of clearing invasive plant species. For A. longifolia on Portuguese dunes, recently invaded areas should be prioritized and thick litter layers should be removed along with the invader. Even so, recovery of native flora was not complete in this study, and other management actions are needed to supplement clearing operations, for example propagation of native species or prescribed fires to deplete the invasive species seed bank. Although complete restoration of the ecosystem will almost always be impossible, it should be possible in the long term to create an ecosystem with a structure and function that resembles the original habitat. [ABSTRACT FROM AUTHOR]

Naked oat (Avena sativa L.) grown in Québec, Canada, produces an average of 10% covered grains. The objectives of this study were to evaluate the effects of environment, herbicide, and genotype on the proportion of covered grains, to study the relation between the presence of awns and the proportion of covered grains, and to determine the location of covered grains on the plant (tiller) and on the panicle. Eight oat lines were evaluated over 2 yr at four experimenta! sites. Each line was treated with bromoxynil! MQPA, dicamba/MCPA, orthifensulfuron methyl! tribenuron methyl applied at Zadoks 12-13 and cOmpared to a hand-weeded check. The highest percentages of covered grains, 5.5 and 6.9%, were found at different sites in 2006 and 2007. The application of dicamba/MCPA increased the percentage of covered grains in the lines normally producing a higher proportion of covered grains, but low producing lines were less affected. Minor differences were found among the other weed control treatments. No relation was found between the presence of awns and the proportion of naked grains. Covered grains were mostly produced on the main stem and their position on the panicle depended on genotype and weed control treatment. [ABSTRACT FROM AUTHOR]

Chlorotoluron (Chl) is a phenylurea herbicide and is widely used for controlling weeds. While it has brought great benefits to crop production, it has also resulted in contamination to ecosystem. In this study, we investigated accumulation of chlorotoluron (Chl) and biological responses of wheat plants as affected by dissolved organic matter (DOM). Wheat seedlings grown under 10 mg kg−1 Chl for 4 d showed a low level of chlorophyll accumulation and damage to plasma membrane. The growth was inhibited by exposure of chlorotoluron. Treatment with 50 mg DOC kg−1 DOM derived either from sludge (DOM-SL) or straw (DOM-ST) attenuated the chlorotoluron toxicity to plants. Both DOMs decreased activities of catalase, peroxidase and superoxide dismutase in Chl-treated seedlings. However, an increased glutathione S-transferases activity was observed under the same condition. Wheat plants treated with Chl in the presence of DOM accumulated less Chl than those treated with Chl alone. Moreover, in the presence of DOM, bioconcentration factor (BCF) decreased whereas translocation factors increased. Analyses with FT-IR spectra confirmed the regulatory role of DOMs in reducing Chl accumulation in wheat. [Copyright &y& Elsevier]

The article focuses on the proposed sterile-female technique for Striga hermonthica and other intractable parasitic weeds control. It mentions that the new technique will target the genes of the weeds species' genome to induce female sterility through pollen from female-sterile target plants without induction and spread via weed population. It imparts that large amount of time involved, labor and resources; and allogamy reliance for female sterility dissemination are the essential shortcomings of the proposed technique. The release of these trasngenic organisms will also threaten related organisms of contamination from the gene flow. It adds that the success of the technique requires several improvements in both transgenic technology and biological knowledge on Striga system.

It has been hypothesized that elevated levels of atmospheric CO2 ( eCO2) may facilitate the encroachment of woody plants into grasslands by reducing water stress. In east-central Minnesota, sandy soils frequently create drought conditions for plants, and water limitation inhibits the establishment of oaks into old fields situated on these soils. Some have argued that eCO2 should slow secondary succession by favoring fast-growing early successional species. However, if oak encroachment into old fields is being inhibited by water stress, then eCO2 could accelerate old-field succession in this region. The purpose of this study was to test the hypothesis that eCO2 will increase the establishment success of oak seedlings in an old field environment. The study was conducted with CO2 levels controlled by free air CO2 enrichment (FACE). In May 1999, four oak ( Quercus ellipsoidalis) acorns were planted in each of 24 plots in each of six experimental FACE rings ( n= 576), three of which received elevated levels (550 ppm) of CO2. Half the plots in each ring were weeded during the first three summers of the experiment. In summer 2000, water input was manipulated during a 3.5-week period, during which half the plots received regular watering while the other half received no water. Summer 2001 was dry, receiving 35% less rainfall than the mean level. Under hot and dry conditions, eCO2 increased soil water levels in unweeded plots and enhanced oak establishment (survival and growth) in weeded plots. In 2006, after the eighth growing season following planting, survival was five times greater under elevated than ambient CO2. The results showed that under hot and dry conditions, eCO2 can act like a nurse plant for tree seedlings growing in bare and unshaded areas, increasing seedling survival and growth, and thereby expanding the establishment window for trees encroaching into a grassland environment. [ABSTRACT FROM AUTHOR]

Abstract: An actor-participative project on sustainable weed control on pavements was started in 2000 in the Netherlands. The aim of the project was to develop a new concept of weed management that provides cost-effective and environmentally sound weed control. Early in 2002, practical guidelines were drawn up in support of decision making by managers of pavements, and weed control contractors. The guidelines are focused mainly on reduction of herbicide use and emission thereof. The new concept was tested in 2002 and 2003 in nine Dutch municipalities on defined urban areas of 5–25ha, which formed units from a construction, hydrology and management point of view. Use of herbicides (mainly glyphosate) was reduced by 11–66% compared to standard practice. Levels of weed control remained good and ecological threshold concentrations in surface waters were not exceeded. Monitoring showed a glyphosate emission factor via the sewage water system of 2% on average. Costs of weed control with the new concept were higher (10–25%) compared to the standard practice control of weeds (using herbicides) on pavements, but much lower compared to alternative (non-herbicide) weed control systems. It is concluded that the new concept provides a useful framework for finding a good trade off between economical and ecological aspects of weed control on pavements. [Copyright &y& Elsevier]