Experimental and empirical evidence shows that reducing weed control in winter cereal fields is a viable strategy for farmers.

Modern agriculture needs a paradigm shift to make the world's food production sustainable while mitigating social and environmental externalities. Although various policies to limit the use of agrochemicals have recently been implemented in the European Union, the use of both herbicides and fertilizers has remained fairly constant. Farmers are assumed to behave optimally, producing the best they can, given the agronomic constraints of their fields. Based on this assumption, reducing agrochemicals should inevitably have negative effects on food production, or reduce farmers' incomes. Coupling empirical analysis based on field surveys and experimental trials where weed management and nitrogen input were manipulated in the same production fields and under real farming conditions, we demonstrate that high use of N fertiliser or intense weed control slightly increase yields, but that this increase is not enough to offset the additional costs incurred by their use. Our experimental design allowed inputs to be varied in a two-factor design, along a gradient spanning from organic to highly intensive farming, while holding all other conditions constant and thus avoiding confounding effects. Quantification of crop yields and gross margins from winter cereal farming showed that reducing dependence on weed management may not hamper cereal production in this system, and is economically profitable at the field level on the short term. Our study thus contributes to addressing a key gap in our economic knowledge, and gives hope for implementing win-win strategies for farmers and the environment.

[Analysis of cost-effectiveness of molluscacide combined with herbicide by spraying].

OBJECTIVE: To explore an economical and efficient molluscicidal method suitable for large area of nursery stock field. METHODS: Two nursery stock fields with Oncomelania hupensis were selected as experimental sites, and an experimental group and a control group were set. In the experimental group, the molluscacide and herbicide were alternately used (a purification molluscicidal method) during the period of May to October, 2011. In the control group, grass shoveling and soil burying combined with molluscacide were used in the same period. The snail control effects of the two groups were observed and the costs of the two methods were analyzed. RESULTS: No living snails were found in both experimental and control groups three consecutive years after the snail control intervention above mentioned. The costs of snail control intervention in the experimental group and control group were 0.90 and 1.80 Yuan/m2, respectively. CONCLUSION: The effect of the purification molluscicidal method in nursery stock field is satisfying, and the cost is lower.

Technoeconomic analysis of large scale production of pre-emergent Pseudomonas fluorescens microbial bioherbicide in Canada.

The study presents an ex ante technoeconomic analysis of commercial production of Pseudomonas fluorescens BRG100 bioherbicide in Canada. An engineering economic model is designed in SuperPro Designer® to investigate capital investment scaling and profitability. Total capital investment for a stand-alone BRG100 fermentation plant at baseline capacity (two 33,000L fermenters; 3602tonnesannum(-1)) is $17.55million. Total annual operating cost is $14.76million. Raw materials account for 50% of operating cost. The fermentation plant is profitable over wide operating scale, evaluated over a range of BRG100 prices and costs of capital. Smaller plants require higher NPV breakeven prices. However, larger plants are more sensitive to changes in the cost of capital. Unit production costs decrease as plant capacity increases, indicating scale economies. A plant operating for less than one year approaches positive NPV for periods as low as 2months. These findings can support bioherbicide R&D investment and commercialization strategies.

Would banning atrazine benefit farmers?

Atrazine, an herbicide used on most of the US corn (maize) crop, is the subject of ongoing controversy, with increasing documentation of its potentially harmful health and environmental impacts. Supporters of atrazine often claim that it is of great value to farmers; most recently, Syngenta, the producer of atrazine, sponsored an "Atrazine Benefits Team" (ABT) of researchers who released a set of five papers in 2011, reporting huge economic benefits from atrazine use in US agriculture. A critical review of the ABT papers shows that they have underestimated the growing problem of atrazine-resistant weeds, offered only a partial review of the effectiveness of alternative herbicides, and ignored the promising option of nonchemical weed management techniques. In addition, the most complete economic analysis in the ABT papers implies that withdrawal of atrazine would lead to a decrease in corn yields of 4.4% and an increase in corn prices of 8.0%. The result would be an increase in corn growers' revenues, equal to US$1.7 billion annually under ABT assumptions. Price impacts on consumers would be minimal: at current levels of ethanol production and use, gasoline prices would rise by no more than US$0.03 per gallon; beef prices would rise by an estimated US$0.01 for a 4-ounce hamburger and US$0.05 for an 8-ounce steak. Thus withdrawal of atrazine would boost farm revenues, while only changing consumer prices by pennies.

Market-level assessment of the economic benefits of atrazine in the United States.

BACKGROUND: Atrazine and other triazine herbicides are widely used in US maize and sorghum production, yet the most recent market-level assessment of the economic benefits of atrazine is for market conditions prevalent in the early 1990s, before commercialization of transgenic crops. Grain markets have changed substantially since that time; for example, the size of the US maize market increased by 170% from 1990-1992 to 2007-2009. This paper reports a current assessment of the economic benefits of atrazine. RESULTS: Yield increases and cost changes implied by triazine herbicides are projected to reduce maize prices by 7-8% and sorghum prices by 19-20%. Projected consumer benefits from lower prices range from $US 3.6 to 4.4 × 10(9) annually, with the net projected economic benefit for triazine herbicides to the US economy ranging from $US 2.9 to 3.4 × 10(9) annually because lower prices imply reduced producer income. Productivity gains from triazine herbicides maintain an estimated 270 000-390 000 ha of land in non-crop uses that generate environmental benefits not accounted for in this analysis. CONCLUSION: Even in the current era, with transgenic varieties dominating crop production, atrazine and the other triazine herbicides continue to be a key part of maize and sorghum production and generate substantial economic benefits.

Composite hollow fiber nanofiltration membranes for recovery of glyphosate from saline wastewater.

A high performance versatile composite hollow fiber nanofiltration (NF) membrane is reported for the separation of glyphosate from saline waste streams. Preparation of SPEEK based on an amorphous poly (ether ether ketone, PEEK) was investigated. The membrane was prepared by coating sulfonated polyether ether ketone (SPEEK) onto a polyethersulfone (PES) ultrafiltration (UF) hollow fiber membrane. The composite membrane was characterized by water permeability, scanning electron microscopy, and rejection toward sodium sulfate (Na2SO4), sodium chloride (NaCl), and calcium chloride (CaCl2). About 90% rejection toward sulfate anions and only 10% rejection for calcium cations were obtained. A water permeability around 10-13 LMHBar and 90% rejection for polyethylene glycol (PEG) with a molecular weight of 4000-6000 Da were observed. In the separation of glyphosate from saline wastewater, the membrane rejected less than 20% of NaCl and higher than 90% of glyphosate at an operating pressure of 5 bars and pH = 11.0. An economic analysis indicated that the cost for recovery of glyphosate was comparably low to the value gained by an increase in the productivity. The results may lead to a new promising low energy solution for the environmental problem faced by the herbicide industry.

Production cost analysis and use of pesticides in the transgenic and conventional corn crop [Zea mays (L.)] in the valley of San Juan, Tolima.

A survey of 10 producers of conventional corn (Hybrids PAC 105 and Maximus) and 10 producers of transgenic corn (Pioneer Hybrid 30T17) was carried out in the municipality of Valle de San Juan in the territorial division of Tolima (Colombia), in order to analyze the differences in production costs and environmental impacts of these two agricultural technologies.  The environmental impacts were determined by calculating the field "Environmental Index Quotient" (EIQ). In the production cost analysis, a difference of 15% was found in benefit of the transgenic technology. The structure of costs of the transgenic technology was benefited by the reduced use of pesticides (insecticides and herbicides). In regards to production, the transgenic technology showed a greater yield, 5.22 ton/ha in comparison to 4.25 ton/ha the conventional technology, thus a 22% difference in yield. Finally, the EIQ calculation showed quantitative differences of 196.12 for the conventional technology (EIQ insecticides 165.14 + EIQ herbicides 30.98), while the transgenic technology was of 4.24 (EIQ insecticides 0 + EIQ herbicides 4.24). These results show a minor environmental impact when using the transgenic technology in comparison to the conventional technology, in regards to the use of insecticides and herbicides in a temporal, spatial and genotypical context analysis. :

Herbicide-resistant weed management: focus on glyphosate.

This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds.

A qualitative meta-analysis reveals consistent effects of atrazine on freshwater fish and amphibians.

OBJECTIVE: The biological effects of the herbicide atrazine on freshwater vertebrates are highly controversial. In an effort to resolve the controversy, we conducted a qualitative meta-analysis on the effects of ecologically relevant atrazine concentrations on amphibian and fish survival, behavior, metamorphic traits, infections, and immune, endocrine, and reproductive systems. DATA SOURCES: We used published, peer-reviewed research and applied strict quality criteria for inclusion of studies in the meta-analysis. DATA SYNTHESIS: We found little evidence that atrazine consistently caused direct mortality of fish or amphibians, but we found evidence that it can have indirect and sublethal effects. The relationship between atrazine concentration and timing of amphibian metamorphosis was regularly nonmonotonic, indicating that atrazine can both accelerate and delay metamorphosis. Atrazine reduced size at or near metamorphosis in 15 of 17 studies and 14 of 14 species. Atrazine elevated amphibian and fish activity in 12 of 13 studies, reduced antipredator behaviors in 6 of 7 studies, and reduced olfactory abilities for fish but not for amphibians. Atrazine was associated with a reduction in 33 of 43 immune function end points and with an increase in 13 of 16 infection end points. Atrazine altered at least one aspect of gonadal morphology in 7 of 10 studies and consistently affected gonadal function, altering spermatogenesis in 2 of 2 studies and sex hormone concentrations in 6 of 7 studies. Atrazine did not affect vitellogenin in 5 studies and increased aromatase in only 1 of 6 studies. Effects of atrazine on fish and amphibian reproductive success, sex ratios, gene frequencies, populations, and communities remain uncertain. CONCLUSIONS: Although there is much left to learn about the effects of atrazine, we identified several consistent effects of atrazine that must be weighed against any of its benefits and the costs and benefits of alternatives to atrazine use.

Economic impacts of glyphosate-resistant crops.

Glyphosate-resistant crops have been widely planted since their introduction in 1996. Growers have numerous choices for herbicide treatments and have chosen to plant glyphosate-resistant crops on the basis of economic factors. The economic effects of the widespread planting of glyphosate-resistant crops have included reductions in herbicide expenses, increases in seed costs, increased yield and changes in the relative profitability of crops that has resulted in changes in which crops are planted. In addition, non-pecuniary benefits have accrued as a result of the simplicity of weed management in the glyphosate-resistant crop systems.

The economics of atrazine.

It is often claimed that atrazine is of great economic benefit to corn growers, but support for this claim is limited. Some cost-benefit studies have assumed that atrazine boosts corn yields by 6%; an extensive review found a 3%-4% average yield increase; other research suggests only a 1% yield effect. Syngenta, the producer of atrazine, also makes mesotrione, an alternative herbicide that does about the same amount for corn yields as atrazine. Italy and Germany both banned atrazine in 1991, with no decrease in corn yields or harvested area. Even if atrazine leads to 6% more corn production, it is not certain that this would justify its continued use; a 1%, or perhaps zero, change does not warrant large-scale exposure of humans and the environment to this potentially hazardous chemical.

The economical efficiency of classic and no-tillage system at genetical modified soybean in conditions of Romania.

The technology of maize without plough land possible to apply in USA and other countries with advanced agriculture, only by atrazine and simazine herbicides synthesis by J. Geigy Company from Switzerland Phillips and Young (1973) said in their book that in USA is practicing no-tillage system on millions acres. After recently dates published by Derpsh (2001) in USA no-tillage is practice on 21,120,000 ha, in Brazil on 14,330,000 ha, in Argentina 10,500,000 ha etc. The chernozem soil in Romania is very properly for no-tillage system. First experiments with no-tillage system have been since 1965 at maize, and at soybean since 2002 until 2005, obtaining remarkable results concerning maize and soybean yields. At genetically modified soybean crop the economic efficiency is very big because fuel consumption was 75 l/ha at classic system and only 21 l/ha at no-tillage system. The expenses with mechanical working were 217 Euro/ha at classic system and only 45 Euro/ha at no-tillage system.

Economic and herbicide use impacts of glyphosate-resistant crops.

More than 95% of United States maize, cotton, soybean and sugarbeet acres are treated with herbicides for weed control. These products are used to improve the economic profitability of crop production for farmers. Since their introduction in 1996, over 75 million acres of genetically engineered glyphosate-resistant crops have been planted, making up 80% of soybean acres and 70% of cotton acres in the USA. These genetically engineered crops have been adopted by farmers because they are perceived to offer greater economic benefits than conventional crop and herbicide programs. The adoption of glyphosate-resistant crops has saved US farmers 1.2 billion dollars associated with the costs of conventional herbicide purchases, application, tillage and hand weeding. With the adoption of glyphosate-resistant sugarbeets on currently planted sugarbeet acres, US growers could potentially save an additional 93 million dollars. The adoption of glyphosate-resistant crops by US agriculture has reduced herbicide use by 37.5 million lbs, although the adoption of glyphosate-resistant sugarbeets would dampen this reduction by 1 million lbs.

Addition of a monovalent cationic pesticide to improve efficacy of bipyridyl herbicides in Hulah Valley soils.

Bipyridyl herbicides are widely used in agriculture and gardening for non-selective weed control. Since they are toxic and relatively expensive, it is ecologically and economically desirable to reduce the amounts applied. A decrease in efficacy of these herbicides is caused by dust accumulated on leaves of weeds. This inactivation arises from the adsorption of the herbicides on dust particles, mainly made of clay minerals, lime and soil organic matter. In order to improve the efficacy and so lower the amounts applied, formulations were developed which include cationic pesticides approved for agricultural use, such as mepiquat or difenzoquat. Such addition restored the efficacy of the bipyridyl herbicides by reducing their binding to dust particles. The proposed formulations, which were tested on a number of different dust-covered plants, allowed the amounts of herbicide applied to be reduced to 50% of the minimum recommended rate. Neither mepiquat or difenzoquat had any herbicidal activity when sprayed alone at the added rates. The results suggest a procedure that may lower the required rates of contact herbicides, reducing costs and toxicity. This procedure, which can be applied immediately, may have broad implications in farming and gardening.

Mycorrhizal growth in pure cultures in the presence of pesticides.

The effects of pesticides on 64 ectomycorrhizal fungi of boreal forest trees were studied in vitro. The pesticides (fungicides: benomyl, chlorothalonil, copper oxychloride, maneb and propiconazole; herbicides: chlorthiamid, glyphosate, hexazinone, linuron and terbuthylazine; insecticide: cypermethrin) were selected as those commonly used in Nordic forest nurseries and afforestation sites. In general, the fungicides proved to be more toxic to ectomycorrhizal fungi than the herbicides and cypermethrin. The fungicides, chlorothalonil and propiconazole, had the clearest inhibitory effect on growth of mycorrhizal fungi. Conversely, maneb, glyphosate and terbuthylazine stimulated the growth of some mycorrhizal fungi. Leccinum versipelle and L. scabrum, Paxillus involutus and Cenococcum geophilum were the most sensitive ectomycorrhizal fungi to the various pesticides.