Why is earthworm needed?

Earthworm may not be different from being a gift from God to increase the fertility of the soil. Quality soil requires two things - porosity and aeration, which earthworm works day and night to match. Earthworms, which help break down organic particles (which are their main food) in the soil and make them soluble, eat twice their body weight a day and continuously excrete, their excretion makes the soil healthier. Research has shown that their excretion contains 5 times more nitrogen, 7 times more phosphorus and 11 times more potassium than normal soil. They also help to increase the number of beneficial bacteria in the soil. That's why they are called" Intestine of the Earth" by Aristotle.

What are the main causes of earthworm death in the field?

There may be many reasons, but one of the main problems is the unnecessary use of inorganic fertilizers, pesticides and insecticides in the field. Earthworm need suitable soil temperature, moisture, pH, humidity, salt, aeration and texture for earthworm to live [4]. Some nitrogenous fertilizers like urea, which is used in farming to increase productivity decreases soil Ph which is unfavorable for earthworm to live. It is scientifically proven that lethal toxic concentration of Urea to Eisenia fetida (a species of earthworm) is 28 µg/cm2[1]. Another research finding gives a fascinating data, earthworm dies within 48 hours if exposed on urea at concentration of 5 mg/ml and 6 hours is more than enough to kill earthworm at the concentration of 80 mg/ml [1]. In Eudrilus eugeniae (Kinberg earthworms), it is the finding highest per cent mortality of 100 % was recorded with urea @10g/kg vermifeed Followed by MOP @ 10g/kg vermifeed (95.00%) [5]. This is the reason urea is categorized under “very toxic” in toxicity grade. Looking at another example, Glyphosate is one of the most used herbicides which is available in 1% solution in the market, 0.01% solution can easily kill the most population of the earthworm [4].

Let’s save Earthworm:

It seems that immediate solutions are needed but some efforts are being made which are not happening at a remarkable pace. I think now we should run farmers' awareness campaign and also analyze the government's subsidy for fertilizers. Due to the increasing subsidy in chemical fertilizers, its usage is increasing at the rate of 20% per year [2]. But the use of organic manure has not been as successful as expected. Therefore, it is time to attract farmers to use organic manure and biofertilizers in appropriate quantities. Fertilizers should preferably be applied on soil test basis as demand of fertilizer may not be same in all type of soil and geography. Similarly, there should be rules and regulations to protect the inappropriate use of chemical fertilizers and to minimize the harm caused by them. The concept of integrated agriculture (like fish cum rice farming) can also help reduce the use of pesticides and insecticides in crops. Nowadays, new solutions have come up for manure. Earthworm manure, compost or green leaf manure, press-mud / composted coir-pith, Azolla, Azospirillum culture, etc. are some moving example. Organic farming is a global topic at this moment, and we have to move towards this practice. Integrated pest management should be applied in farmers level. Opting organic farming will create a healthy natural environment and ecosystem for the present as well as future generation soil organisms [3]. Tillage farming gives negative effect on worm population in the soil. Some seasonal grasses and plants can be planted so that it can be used as manure later in the field. Agriculturists and environmentalists can also play a role in social awareness. But we all have the same responsibility to protect the worm friendly soil environment.

References:

[1] Dash, A., & MOHAPATRA, S. S. (2018). Toxic Effect of Urea on Earthworms Determined by a Simple Paper Contact Method. Innovare Journal of Agricultural Sciences, 6(1), 17-19. https://doi.org/10.22159/10.22695

[2] Bista, Diwas & Dhungel, Sujan & Adhikari, Santosh. (2016). Status of fertilizer and seed subsidy in Nepal: review and recommendation. Journal of Agriculture and Environment. 17. 1-10. 10.3126/aej.v17i0.19854.

[3] Chandini, & Kumar, Randeep & Kumar, Ravendra & Prakash, Om. (2019). The Impact of Chemical Fertilizers on our Environment and Ecosystem.

[4] https://www.thatsfarming.com/news/worms-farmers-friend

[5] Shruthi N, AP Biradar and Syed Muzammil. Toxic effect of inorganic fertilizers to earthworms (Eudrilus eugeniae). Journal of Entomology and Zoology Studies. 2017; 5(6): 1135-1137.