GM crops, best killer of soil microbes, booster of crop yields

Farming in Ghana

Genetically Modified (GM) crops are crops whose genetic material has been modified through the introduction of a gene from a different organism. Most GM crops have been developed to improve yield through the introduction of resistance to plant pests or of increased tolerance of herbicides.

The cultivation of these crops allow for reductions in food prices through improved yields and reliability. On the global scale, all GM foods currently available on the markets have passed safety assessments and do not have any negative effects on human health.

As far as the safety of GM crops are concerned, the World Health Organization (WHO) considers three main issues when discussing and developing GM foods.

The first is allergenicity which means the ability of the edited genes or food product to cause an allergic reaction. To date, no allergic effects have been found relative to GM foods currently on the market.

The second is the transfer of genes from GM foods to the human digestive tract. The probability of transfer is low and the WHO recommends the use of gene transfer technology that does not involve antibiotic resistance genes.

Finally, the third is outcrossing which means the transfer of genes from GM crops to their non-GM relatives. For instance, how can we be sure that pollen from a GM cowpea field will not cross to fertilize a nearby non-GM cowpea field? If this is an issue of concern that is considered undesired, the simple solution is to use physical separation of crop fields to prevents this from happening.

Apart from food safety issues, persons opposed to biotechnology claim GM crops kill soil microbes. This is FALSE. Healthy soils are fundamental to any productive agricultural system. There cannot be agricultural production without healthy soils. Soil health is evaluated based on how it promotes plant growth and productivity According to Nboryine et all(2020).

They said, the parameters used as indicators of healthy soils include the physical, chemical and biological (soil enzymes, microorganisms and their activities, etc.) properties of the soil. In relation to the biological properties of soil, soil is a habitat for a diverse range of organisms and contributes to carbon sequestration.

However, current farming practices such as mechanical land preparation and weeding are harmful to most components of the biological properties of soil. These practices cause soil erosion and runoff, thus affecting soil biodiversity. Greenhouse gases also escape from the soil because of these practices.

According to World Wildlife Fund, half the world’s soil has been lost in the recent 150 years due to mechanical weed control and ploughing. Mechanical weed control hurts these organisms by exposing them to the sun.

This exposure to the sun mostly kills them. Sometimes, the blade of the hoe used to weed also cuts them into two consequently killing them. In other instances, they are exposed to birds or other above ground animals that prey on them.

These negative consequences have led to the promotion of no tillage practices as a sustainable way of farming. Loss of soil biodiversity including soil microbes has therefore got little to do with GM crops.

On the contrary, GM crops such as the herbicide tolerant ones helps to conserve soil microbes because their cultivation promote no-till or conservation tillage practices. Farmers who cultivate herbicide tolerant crop varieties do not disturb or hurt soil dwelling micro-organisms because they do not have to mechanically weed their fields. Hence, our farming practices is responsible for killing the microbes but not the cultivation of GM crops according to Nboyine et al(2020).

For GM crops that are developed to withstand damage by a particular insect pest (i.e.,  Bt crops), it is argued that the protein that kills the target pest accumulates in the roots of the plant and soil, consequently killing soil microbes. This is also FALSE. There are over 70 scientific articles that have been published in the last decade on this subject according to Nbotine et al(2020).

The findings of all these articles authored by different scientists show no toxic effect of Bt crops to soil microbes. Some soil micro-organisms that were studied included woodlice, collembolans, mites, earthworms, nematodes, protozoa, as well as the activity of different enzymes in soil. These studies were conducted using Bt and non-Bt maize or cotton.

Different forms of the Bt protein were studied on these organisms and none of these studies found significant negative effect of the protein on soil microbes.

To further show that the Bt protein is not harmful to soil microbes, field experiments have been conducted to study the effect of Bt proteins on soil organisms responsible for decomposition. Again, when Bt and non-Bt maize were exposed to decomposers, scientists did not find decomposition of these two categories of crop by the microbes being different.

In view of this, the Savanna Agricultural Research Institute of the Council for Scientific and Industrial Research(CSIR-SARI) has been collaborating with the colleague research scientist in other countries to ensure farmers access quality, certified  and secured seeds for their productions without any harmful effect.

“CSIR-SARI  would continue to  ensure that early generation seeds of those varieties were produced and made available to certified seed growers to produce and supply to farmers for the next farming season under the Planting of Food and Jobs (PFJ)programme across the country” they said.

As scientists in Ghana prepare to apply for environmental release of Bt Cowpea, many persons opposed to the technology may attempt to discredit the benefit of Bt crops in general to our socio-economic development.

We must however, note that science is not based on emotions but on facts/data. To date, there is no concrete data in the scientific arenas to support assertions that GM crops kill soil microbes.

Some farmers who have benefitted from the field trial in an interview called on government and other stakeholder ensure approving of the variety to enable the farmers access them from their productions.

They were of the view that per the sensitization, the variety does not contain any side effect but rather boost the soil nutrients for other crop productions.


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