IMPACT OF GMO CROPS ON SOIL HEALTH
IMPACT OF GMO CROPS ON SOIL HEALTH
- Genetically Modified Crops
- What are GMOs
- Why GMO are produced?
- Examples of GMO Crops
- People interest toward GMO
- At International level
- In Pakistan
- Importance of Soil Health
- Studies on impact of GMO Crops on Soil Health
- Positive views
- Negative Views
- Use of Agro-Chemicals on GMO
- Bt toxin
- Spread of Recombinant DNA
- Pollen Release
- Effect on Microbes
- Direct Effect
- In-direct effect
- Effect on Earthworm
- Effect on Bacteria and Fungi
Genetically Modified Organisms (GMO) shows beneficial potential towards agriculture and health of human in environmentally friendly way. The large number of reports on risk of ecology and beneficial points of GM plants give stress on that there is a need for experimental work to observe the effects of GMO crops on soil health. The major concern of GMO crops is their effect on non-target soil micro-organisms that are playing an essential role in decomposition of crops residuals and recycling of bio-elements. Recently there is a work on effects of GMO crops on soil health by using targeted and non-targeted organisms. In this review there is a discussion on impact of GMO crops on soil health, microbes communities present in soil and other long lasting effects even after harvest of GMO crops.
Genetically modified crops shows beneficial aspects towards environment and health of human beings. Poor knowledge is available on this aspect that what happens if scientists are doing genetic modification in plants. The risk of ecology and benefits gained from GMO crops give stress on that there must be experimental work to evaluate the impact of GMO crops on environment and to observe effects after release of GMO crops in fields.’’ Everything goes everywhere’’ and gene can flow from one organism to other organism (Hooykaas 1989).Unintended effects of genetic manipulation proved by an example of Agro bacterium tumefaciens that causes of host DNA disruption (Szabados et al. 2002).GMO crops also affects microbial communities in soil because 20% of assimilates released by plants in soil as roots exudates at the end of production cycles (Whipps 1990).In this review GMO crops ,why GMO are produced ,examples of GMO ,GMO crops effects on soil health and on microbial communities are discussed.
Genetically Modified Crops:
Genetically modified crops are those in which researchers and scientists make genetic manipulation in genome of crops for getting benefits for humanity. These manipulations may be for increasing yield of a crop, for making a crop pesticide resistant or drought resistant or herbicide resistant, insect resistant and many other such aspects. Genetically modified crops are developed because population of the world is increasing day by day, fertility and potential of soil is decreasing due to cropping system, there are number of problems are present in crops like insect or pest attack, diseases (bacterial or viral).Due to these problems yield and production of crops are not enough to feed the increasing population of the world. Scientists and researchers moved toward GMO so that by understanding the genome of crops or organisms the basics of problems can be solved by genetic manipulation. Many crops are genetically manipulated for example Maize, Wheat, Bt cotton, Bt Brinjal, Canola etc.
People Interest toward GMO crops:
People are showing two types of behavior towards GMO crops. First type of people having views that GMO crops are beneficial for humanity. It is due to genetic manipulation in crops genome that scientists and researchers are able to make pesticide resistant crops, insecticide resistant crops, drought resistant crops, herbicide resistant crops, high yielding crops, water shortage resistant crops and many others such aspects. At international level very few people are accepting GMO crops. A large number of people are not accepting the GMO crops due to effects of GMO on environment, human and on soil health. A real example of behavior of international people is that Pakistan is exporting rice in international market and genetic manipulation is banned in Pakistan because people at international market are not ready to accept GMO rice. In Pakistan same behavior is shown by people some are accepting the GMO and a large number of people are not ready to accept the GMO crops.
Importance of Soil Health:
Soil health concerns the production of crops. The soil which has more microbial communities is known as healthy soil. It is necessary to study the effect of GMO crops on microbial communities of soil and also on soil health. There is not a lot of study to observe the effect of GMO crops on soil health because scientists are not sure about this matter. The use of agro- chemicals is increased on GMO crops because GMO crops are resistant to it. These agro-chemicals adversely affect the microbial communities of soil and soil health. Cry 1 Ab protein of transgenic Bt corn is degraded in field (Zwahlen et al., 2003a). When there is a destruction of microbial communities in soil then recycling of organic elements and nitrogen fixation for plants are surely stopped. As a result the efficiency of soil to grow crops is decreased.
Impact of GMO crops on Soil Health:
In a positive way, GMO crops are resistant to insects, pests and weeds so there is no need for insecticides, pesticides and herbicides. As a result the destruction of microbial communities and soil health is not taken place which gives us a healthy soil.
Negative views about impact of GMO crops on soil health:
In a negative way, GMO crops are resistant to agro-chemicals so scientists use agro-chemicals on GMO crops which ultimately result of destruction of soil health as well as microbes of soil. Bt crops (cotton, Brinjal) release Bt toxin in soil which is harmful for microbes present in soil. Toxins or proteins released by Bt crops in soil persist in field in growing period of crops as well as after harvesting of crops up to 234 days (US EPA (2001) Report from the FIFRA Scientific Advisory Panel Meeting, October 18-20 on Bt Plant-Pesticides Risk and Benefit Assessment). DNA of pollen producing GMO crops present at a distance of 50 meters inspite of containment strips and DNA of GMO crops persists in field for at least a year (Meier and Wackernagel 2003). Pollen of GMO Crops may spread to other crops and may a result of supra-weed.
Effect on Microbes:
GMO crops affect the microbial communities of soil along with the soil health. GMO crops affects the microbes may be directly or indirectly. In direct effect GMO plants released toxins in soil which proves harmful for microbes. Indirectly, metabolic pathway of GMO plant is modified to change the root exudates composition and change expression of plant tissues. In most of GMO crops, Cauliflower Mosaic virus 35S promoter is used which ultimately increases the environmental hazards (Ho et al. 1999). Transgenic GMO also effects the earthworm population (Zwahlen et al. 2003b). It is due to feeding on Bt crops those earthworm losses its about 18% initial weight. GMO crops also affect bacteria and fungi. The toxins released by GMO crops in soil persist in field after harvesting of crops which ultimately harmful for target and non-target microbes which are responsible for degradation in soil and recycling.
- GMO crops have both negative and positive effects on soil health.
- Some people are thinking that GMO crops are healthy for soil health and its microbial communities.
- Because on GMO crops there is no need for insecticides, pesticides and herbicides which is beneficial for microbes present in soil that make soil healthy.
- While some people are thinking that GMO crops have negative impacts on soil health.
- GMO crops release toxins in soil which is harmful for microbes (bacteria, fungi, and earthworm).
- DNA of GMO crops persist in field even after the harvesting of GMO crops.
- Agro-chemicals use on GMO crops because GMO are resistant to it and these agro-chemicals is harmful for microbes.
- In the absence of microbes degradation in soil, recycling of organic elements and nitrogen fixation for plants is not carried out which ultimately make soil unhealthy.
- There is a chance that pollen of GMO crops spread and causes of supra weeds.
- By manipulations in GMO crops, we are to make our crops high yielding, insect resistant, pest resistant, herbicides resistant, salt resistant and drought resistant and many more such as benefits to facilitate humanity.
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2.Meier, P. & Wackernagel, W. (2003) Monitoring the spread of recombinant DNA from field plots with transgenic sugar beet plants by PCR and natural transformation of Pseudomonas stutzeri. Transgenic Research 12, 293-304.
- Zwahlen, C., Hilbeck, A., Gugerli, P. Nentwig, W. (2003a) Degradation of the Cry1Ab protein within transgenic Bacillus thuringiensiscorn tissue in the field. Molecular Ecology12, 765-75.
- Zwahlen, C., Hilbeck, A., Howald R., & Nentwig, W. (2003b) Effects of transgenic Btcorn litter of the earthworm Lumbricus terrestris. Molecular Ecology12, 1077-1086
- Siciliano, S.D. & Germida, J.J. (1999) Taxonomic diversity of bacteria associated with the roots of field-grown transgenic Brassica napuscv. Quest, compared to the non-transgenic B. napuscv. Excel and B. rape cv. Parkland. FEMS Microbiology Ecology, 29, 263-272.
- Ahrenholtz, I., Harms, K., de Vries, J. & Wackernagel, W. (2000) Increased killing of Bacillus subtilison the hair roots of transgenic T4 lysozyme-producing potatoes. Applied and Environmental Microbiology, 66, 1862-1865.
- Royal Society of Canada (2001) Elements of precaution: recommendations for the regulation of food biotechnology in Canada. http://www.rsc.ca/.