Effect of Bt-Transgenic Cotton on Soil Biological Health

http://www.indianjournals.com/ijor.aspx?target=ijor:abr&volume=14&issue=1&article=002

Tarafdar Jagadish C.*, Rathore Indira, Shiva Vandana1 Central Arid Zone Research Institute, Jodhpur, Rajasthan-342 003 (India)  1Navadanya, A-60, Hauz Khas, New Delhi 110 016, India  *email: jctarafdar@yahoo.in; tarafdar@cazri.res.in

Bt cotton are plants that have been genetically modified to express the insecticidal proteins Cry 1 Acfrom subspecies of the bacterium, Bacillus thuringiensis israelensis (Bt), to control bollworm pest that feed on cotton. There is a persistent environmental concern that transgenic Bt-crops carry genes that have indirect undesirable effect to natural and agroecosystem function. We investigated the effect of Bt-cotton (with Cry 1 Ac gene) on several microbial and biochemical indicators in fields under sub-humid tropical condition. Twenty five fields were selected in the Vidarbha region, India, where Bt-cotton has been growing at least three consecutive years and side by side field of non-transgenic cotton is growing under clay to clay loam soil. Soil from a control (no-crop) treatment was also included from each area to compare the extent of adverse effect of Bt, if any. Samples were analyzed for actinobacteria, fungi and nitrifiers population, biomass carbon (MBC), biomass nitrogen (MBN), biomass phosphorus (MBP) and soil enzyme activities. The result revealed a significant decline in actinobacteria (17%), bacterial (14%) count as well as acid phosphatase (27%), phytase (18%), nitrogenase (23%) and dehydrogenase (12%) activities in Bt cotton compared with non-Bt cotton fields. Fungal and nitrifier counts, and esterase and alkaline phosphatase activities were not affected by the introduction of Bt-cotton in fields. However, significant decline between 8 and 9% in MBC and MBN was noticed.

 

Genetically modified corn affects its symbiotic relationship with non-target soil organisms

Experimental evidence reveals a reduction in arbuscular mycorrhizal fungal colonization of Bt corn

 IMAGE: Arbuscular mycorrhizal fungi (AMF) colonizing corn (Zea mays) roots as viewed with a compound light microscope (400x). Roots were cleared with 10 percent KOH and stained with 0.05 percent trypan…

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An increasing number of crops commercially grown today are genetically modified (GM) to resist insect pests and/or tolerate herbicides. Although Btcorn is one of the most commonly grown GM crops in the United States, little is known about its effects on the long-term health of soils. Although there are many benefits to using biotechnology in agriculture, such as potentially reducing insecticide use, there may be unintended side effects as well—does GM corn impact non-target soil organisms, such as arbuscular mycorrhizal fungi, or affect plants subsequently grown in the same field?

Bt corn is genetically engineered to express insecticidal toxins derived from a soil bacterium, Bacillus thuringiensis, to protect it against common agricultural pests such as the corn root worm and European corn borer. Tanya Cheeke and her colleagues (at Portland State University, Oregon) were interested in determining whether the cultivation of Bt corn has a negative effect on arbuscular mycorrhizal fungal colonization of Bt corn or of crops subsequently planted in the same soil. They published their findings in a recent issue of theAmerican Journal of Botany (http://www.amjbot.org/content/99/4/700.full).

Arbuscular mycorrhizal fungi (AMF) are ubiquitous microscopic soil fungi that form symbiotic relationships with the roots of most plants. Plants supply the fungi with carbon, and the fungi increase the host plant’s ability to uptake nutrients and water from the surrounding soil.

“Because these fungi rely on a plant host for nutrition and reproduction, they may be sensitive to genetic changes within a plant, such as insect-resistant Btcorn,” stated Cheeke.

By experimentally planting seeds from several different lines of both Bt corn and non-Bt corn, and using local agricultural soil containing native mycorrhizal fungi, the authors were able to simulate what might happen naturally in an agricultural system.

“What makes our study unique is that we evaluated AMF colonization in 14 different lines of Bt and non-Bt corn under consistent experimental conditions in a greenhouse using locally collected agricultural field soil as the AMF inoculum,” said Cheeke.

“The use of whole soil in this study allowed each Bt and non-Bt corn line to interact with a community of soil organisms, making this study more ecologically relevant than other greenhouse studies that use a single species of AMF,” she adds.

Interestingly, the authors found that colonization of plant roots by symbiotic soil fungi was lower in the genetically modified Bt corn than in the control lines. However, there was no difference in root biomass or shoot biomass between the two types of corn at the time of harvest.

Cheeke and co-authors also determined that the Bt-protein itself is not directly toxic to the fungi since AMF colonization of vegetable soybeans did not differ for those grown in soil previously containing Bt vs. non-Bt corn.

Together these findings contribute to the growing body of knowledge examining the unanticipated effects of Bt crop cultivation on non-target soil organisms. Examining non-target effects of genetically engineered crops on symbiotic soil organisms becomes even more important as acreage devoted to the cultivation of Bt crops continues to increase globally.

“In 2011, 88% of the corn cultivated in the United States was genetically modified to express insect resistance, herbicide tolerance, or some combination of stacked traits,” Cheeke commented. “Globally, genetically modified corn is cultivated in at least 16 different countries.”

Cheeke notes that the next step is to understand the ecological significance of this study. “In greenhouse studies Btcorn had lower levels AMF colonization, so now it is important to see if this pattern is also observed under field conditions.” She plans to use field experiments to test if planting a Bt crop for multiple years has an effect on the abundance or diversity of AMF in the soil ecosystem.

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Tanya E. Cheeke, Todd N. Rosenstiel, and Mitchell B. Cruzan. 2012. Evidence of reduced arbuscular mycorrhizal fungal colonization in multiple lines of Bt maize. American Journal of Botany 99(4): 700-707. DOI: 10.3732/ajb.1100529

The full article in the link mentioned is available for no charge for 30 days following the date of this summary athttp://www.amjbot.org/content/99/4/700.full. After this date, reporters may contact Richard Hund at ajb@botany.org for a copy of the article.

The Botanical Society of America (www.botany.org) is a non-profit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. It has published the American Journal of Botany (www.amjbot.org) for nearly 100 years. In 2009, the Special Libraries Association named theAmerican Journal of Botany one of the Top 10 Most Influential Journals of the Century in the field of Biology and Medicine.

For further information, please contact the AJB staff at ajb@botany.org.

Pesticide Exposure in Womb Affects I.Q.

By TARA PARKER-POPE, Editor

pesticides?Pesticides on fruits, vegetables and other household products may lower a child’s I.Q.

Babies exposed to high levels of common pesticides in the womb have lower I.Q. scores than their peers by the time they reach school age, according to three new studies.

The research, based on data collected in New York and California from about 1,000 pregnant women and their babies, is certain to set off a new debate about the benefits of organic produce and the risks of chemicals found in the food supply and consumer products. The pesticides, called organophosphates, are commonly sprayed on food crops and are often used to control cockroaches and other pests in city apartments.

The latest findings are based on three separate but similar studies financed by the National Institute of Environmental Health Sciences and the federal Environmental Protection Agency. Two were conducted by researchers at Mount Sinai School of Medicine and Columbia University and studied urban families in New York; the third was done by researchers at the School of Public Health at the University of California, Berkeley, and focused on children in Salinas, Calif., an agricultural area. All three were published online on Thursday in the journal Environmental Health Perspectives.

Each study began about a decade ago, when researchers recruited pregnant women who gave blood and urine samples that were used to measure pesticide exposure. In some instances, umbilical cord blood was tested. After the babies were born, the researchers continued to monitor the health of the children and also obtained regular urine samples to determine exposure to pesticides.

Over all, the studies found that women who had higher exposures to pesticides during pregnancy gave birth to children who eventually had lower I.Q. scores once they reached school age. In the Berkeley study, for instance, children with the highest levels of prenatal pesticide exposure scored 7 points lower on intelligence tests compared with children with the lowest levels of exposure. In that study, every 10-fold increase in organophosphate exposure detected during pregnancy corresponded to a 5.5 point drop in overall I.Q. scores.

“I think these are shocking findings,” said Dr. Philip Landrigan, a professor of pediatrics and director of the Children’s Environmental Health Center at Mount Sinai. “Babies exposed to the highest levels had the most severe effects. It means these children are going to have problems as they go through life.”

Dr. Landrigan compared the findings with research in the 1980s that linked childhood lead exposure to lower intelligence, dyslexia, higher risk for dropping out of school and a range of behavioral and developmental problems. As a result of that research, lead was removed from gasoline to prevent exposure from car exhaust, and it was also removed from paints and other consumer products.

The drop in I.Q. scores shown in the pesticide studies is similar to the drops shown in the earlier lead research, Dr. Landrigan said.

“When we took lead out of gasoline, we reduced lead poisoning by 90 percent, and we raised the I.Q. of a whole generation of children by four or five points,’’ said Dr. Landrigan. “I think these findings about pesticides should generate similar controversy, but I’m cautiously optimistic that they will have the effect of having the E.P.A. sharply reduce the use of organophosphate pesticides.”

Individuals can also do more to limit their own exposure. In homes with pest problems, sealing up cracks and crevices in baseboards and cleaning up food residue has been shown to be more effective at controlling cockroaches than using pesticides.

Caleb Kenna for The New York Times

Steps can also be taken to minimize exposure to pesticides in foods, particularly among pregnant women. Buying organic foods can help because certified organic fruits and vegetables aren’t grown with organophosphate pesticides. Better washing and peeling of conventionally grown produce can also reduce exposure.

The Environmental Working Group offers a shopper’s guide showing which foods have the highest and lowest rates of pesticide exposure. Strawberries, peaches, celery, apples and spinach typically have the highest levels of pesticide residue among commercially grown fruits and vegetables. Onions, avocado, frozen corn and pineapple had the lowest levels of pesticide residue.

Genetic yield potential of rice (Oryza sativa) through water saving and high-yielding SRI technology

SURENDRA K GHRITLAHRE, ASHOK KUMAR SARIAL, and RATTAN SINGH, MANGAT RAM, DES RAJ ANEJA
CCS Haryana Agricultural University Campus, Kaul, Haryana 136 021

The system of rice intensification (SRI) that evolved in the 1980s in Madagascar is also gaining popularity in India. SRI saves not only the seed (a seed rate of 5–7 kg/ha as against 25–30 kg/ha for normal) but also saves water (35–40%) as the fields are not inundated continuously. It leads to higher ripening ratio and increases yield by 10–25%. The varietal response to SRI and conventional cultivation is wide.  The system of rice intensification (SRI) that evolved in the 1980s in Madagascar is also gaining popularity in India.  SRI saves not only the seed (a seed rate of 5–7 kg/ha as against 25–30 kg/ha for normal) but also saves water (35–40%) as the fields are not inundated continuously. It leads to higher ripening ratio and increases yield by 10–25%. The varietal response to SRI and conventional cultivation is wide. Varieties differed in their genetic potential and all the varieties are not promising for SRI cultivation. There is need to develop/identify varieties that give better response to SRI cultivation. Therefore, the present investigation on comparative evaluation of rice genotypes for yield and its components under SRI and conventional system was undertaken to identify suitable cultivars for SRI. Varieties differed in their genetic potential and all the varieties are not promising for SRI cultivation. There is need to develop/identify varieties that give better response to SRI cultivation. Therefore, the present investigation on comparative evaluation of rice genotypes for yield and its components under SRI and conventional system was undertaken to identify suitable cultivars for SRI.

Are Neonicotinoid insecticides Killing Bees?

A Review of Research into the Effects of Neonicotinoid Insecticides on Bees, with Recommendations for Action

By Jennifer Hopwood, Mace Vaughan, Matthew Shepherd, David Biddinger, Eric Mader, Scott Hoffman Black, Celeste Mazzacano


A possible link between neonicotinoids and honey bee die-offs has led to controversy across the United States and Europe. Beekeepers and environmentalists have expressed growing concern about the impact of neonicotinoids, concern based on the fact that neonicotinoids are absorbed into plant tissue and can be present in pollen and nectar, making them toxic to pollinators.

This report details potential negative impacts of neonicotinoids insecticides to honey bees and other important pollinators. It also makes recommendations on how we can better protect bees.

Click here to view a full PDF of the report.

Some of the major findings of the report include:

  • Several of these insecticides are highly toxic to honey bees and bumblebees.
  • Neonicotinoid residues are found in pollen and nectar consumed by pollinators such as bees and butterflies. The residues can reach lethal concentrations in some situations.
  • Neonicotinoids can persist in soil for months or years after a single application. Measurable amounts of residues were found in woody plants up to six years after application.
  • Untreated plants may absorb chemical residues left over in the soil from the previous year.
  • Products approved for homeowners to use in gardens, lawns, and on ornamental trees have manufacturer-recommended application rates up to 120 times higher than rates approved for agricultural crops.
  • There is no direct link demonstrated between neonicotinoids and the honey bee syndrome known as Colony Collapse Disorder (CCD). However, recent research suggests that neonicotinoids may make honey bees more susceptible to parasites and pathogens, including the intestinal parasite Nosema, which has been implicated as one causative factor in CCD.
  • Many neonicotinoid pesticides that are sold to homeowners for use on lawns and gardens do not have any mention of the risks of these products to bees, and the label guidance for products used in agriculture is not always clear or consistent.

The report recommends that regulators reassess the bee safety of all neonicotinoid pesticide products, reexamine or suspend all conditional registrations until we understand how to manage risks, and require clear labels so that consumers know that these products kill bees and other pollinators.

The report also recommends that the US Environmental Protection Agency adopt a more cautious approach to approving all new pesticides, using a comprehensive assessment process that adequately addresses the risks to honey bees, bumble bees, and solitary bees in all life stages.

Technical adaptations for mechanized SRI production to achieve water saving and increased profitability in Punjab, Pakistan

http://www.springerlink.com/content/e1568029183w1106/fulltext.pdf

Asif Sharif

Even in a country with a large population and rapid population growth, there can be labor shortages in the
agricultural sector, because of out migration of the ablebodied work force. The System of Rice Intensification
(SRI) is not necessarily more labor-intensive once the methods have been learned, but the initial labor requirements can be a barrier to adoption, and farmers with large land areas cannot find the labor needed to use these more productive methods. Recognizing this problem, a set of agricultural implements have been designed for mechanizing the operations of SRI, with a view to reducing water requirements as well as labor requirements because the current conditions for agricultural production in the Punjab region of Pakistan include water scarcity and poor water quality as well as labor shortages. This article reports on the process of mechanizing SRI production in Punjab, which has been quite successful so far. Average yield is considerably increased with a 70% reduction in water requirements and a similar reduction in labor needs. The machinery and methods have been further adapted to other crops, being grown on permanent-raised beds, so that SRI with organic fertilization is combined with Conservation Agriculture. This combination is referred to as ‘‘paradoxical agriculture’’ because it enables farmers to achieve higher outputs with reduced inputs.

The Politics of International Assessments: The IAASTD Process, Reception and Significance

SHELLEY FELDMAN AND STEPHEN BIGGS

Journal of Agrarian Change, Vol. 12 No. 1, January 2012, pp. 144–169.

This paper explores the career of the International Assessment of Agricultural Knowledge Science and Technology and Development (IAASTD) from its inception, the publishing of its reports, and its place in ongoing debates on global agriculture, food security, poverty reduction, social equity and sustainable development.We highlight the disputes and disruptions that characterize the IAASTD process and attempts to marginalize its findings.  Following a brief review of the history of the Assessment and of the social construction of scientific knowledges, we consider five processes that expose the hierarchies and contestations that shape ongoing debates. We reveal how conflicts within IAASTD and between IAASTD and its sponsors cannot be dismissed as either technical or managerial, but instead showcase the fragility of claims that privilege productivity increases over other relations in agricultural practice. We conclude with a challenge to understanding agricultural change and its future that builds on social, ecological and political relations as constitutive rather than
as exogenous to research and policy formation.