Scientists from Indian Institute of Soil Science, Bhopal, and Indian Institute of Agricultural Research, New Delhi, both part of the Indian Council of Agricultural Research (ICAR), have been studying the effects of climate factors and use of insecticides on the ability of soil to consume methane. Their study reveals one of the harmful effects of the insecticide- Chlorpyrifos, and a way to tackle the issue.
Chlorpyrifos is a common pesticide used to control pests, like insects and worms. It has been used in agriculture, residential and commercial settings, being extensively used in cotton cultivation. As the planet continues warming due to climate change; pest infestation is also set to increase, according to earlier studies. With the increased infestation, the use of insecticides also increases, leading to deteriorated soil conditions. As safe alternatives to tackle an infestation still remains a challenge, indiscriminate use of pesticides are starting to take a toll on agricultural farms and biodiversity around the globe.
In the new study, scientists set out to determine the effects of pesticides and climate factors on the ability of a soil to consume methane. Working in a Vertisol (soil with high content clay) in central India, the team studied the effects of temperature, moisture holding capacity, and chlorpyrifos on the ability of a soil to consume methane and abundance of microbes in the soil. The team also studied the effects of adding biochar or charcoal to the soil.
The results of the study reveal a connection between the levels of chlorpyrifos and methane consumption of the soil. The rate and amount of methane consumption of the soil was at a lowest at 15o Celsius temperature, 60% moisture holding capacity, 10ppm chlorpyrifos and no biochar, and highest at 35o C, 100% moisture holding capacity, 1% biochar and no chlorpyrifos. The results also showed that, while chlorpyrifos inhibited the abundance of some types of microbes, like heterotrophic bacteria and methanotrophs, it stimulated the growth of another type of bacteria—Actinomycetes. Importantly, the study also revealed that biochar could stimulate methane consumption of the soil and abundance of microbes. This could provide us a way to tackle some of the harmful effects of chlorpyrifos.
“Study highlighted that use of chlorpyrifos under climate change factors may inhibit CH4 consumption but the use of biochar may alleviate the negative effect of the chlorpyrifos” conclude the authors about the results of the study.