Soil and water

varthur: Loot of lake land

By Garima Prasher

When the Bangalore Development Authority (BDA) has begun restoration work on the Lake Varthur last year he faced a Herculean task to get rid of tons of accumulated silt. However, the BDA had a eureka moment: using silt as manure in the vicinity farming lands. Today, villagers around the lake reap the benefits.

This conservation work has proven to be doubly beneficial for farmers who have started using silt from the lake in their fields.

Yallesh N, a resident of a village near Varthur Lake, is already seeing encouraging results from applying silt to his farmland. According to Yallesh, crop productivity on his farm has increased by more than Rs 1.5 lakh/acre/year.

“My four-acre farmland had eucalyptus cultivation for many years. When the government banned the cultivation and planting of eucalyptus, I had no choice but to clear the field. However, I realized that growing eucalyptus damaged the soil and the quality deteriorated significantly,” Yallesh told BM.

It was around the same time that Yallesh had the opportunity to attend a meeting called by the National Green Tribunal oversight committee on Lake Varthur to educate farmers about using silt as manure. Yallesh attended the meeting and had a few dump trucks of silt transported to his field.

“We plowed the land and mixed the silt with soil. In addition to providing nutrients to crops, this soil-silt mixture slowly absorbs water and maintains a moderate temperature in farmland. We applied the silt last year and will do it again in April this year. Since then, I have been growing green vegetables and productivity has skyrocketed. It has increased by Rs 1.5 lakh/acre/year,” Yallesh said.

According to experts, in traditional agriculture, silt collected from village reservoirs and lakes was reapplied to fields to improve soil fertility. They say the silt from the lake is rich in carbon nutrients and other organic content, thus enriching the soil.

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“Varthur silt is rich in nutrients. Once farmers have applied the silt, they no longer need to use chemical fertilizer. The silt alone doubles crop productivity in the villages surrounding Varthur. Historically, people have used silt from the lakes to grow their crops. But today, this practice is very remote, creating the need for chemical fertilizerssaid Dr TV Ramachandra, Center for Ecological Sciences, IISc, who was part of the NGT monitoring committee on Lake Varthur.

Using silt as manure helps farmers diversify their produce and earn a better living. GK Manjunath Babu, a rose grower from a nearby village around Varthur Lake, is another beneficiary. Manjunath has grown roses on his 4.5 acre plot for generations and said the yield has never increased so much.

“We have been growing roses for 60 to 70 years. But productivity has never been so good. It increased by 60% with the use of Varthur’s Ooze. No amount of fertilizer had done this for me before,” Manjunath said.

According to MA Khan, director, KK High School, Varthur, until a few decades ago farmers in the area used silt from the lake as manure.

“I have seen Lake Varthur since my childhood. I remember villagers collecting the silt in ox carts during the summers to apply to their farmlands. However, with rapid urbanization, sewage began to flow into the lake throughout the year and it never dried up. So the old practice faded,” Khan recalls.

Currently, the BDA transports silt from Varthur to around seven villages within 15 km of the lake’s outskirts and the authority says the demand for silt is increasing.

“We provide free Varthur silt to about seven villages. This affects more than 50 farmers. We have already supplied 2.5 to 3 lakh cubic meters of silt since March 2021 and the demand keeps increasing,” said Aravind SS, Assistant Engineer, BDA.

We have been growing roses for 70 years; productivity has never been so good. It increased by 60% with Varthur’s silt

— GK Manjunath Babu, rose grower

Experts say it is high time for the government to prioritize watershed management programs and ensure that lake desilting is done across the state.

“We have thousands of lakes and reservoirs across Karnataka. If we rejuvenate all the polluted lakes along Lake Varthur, we will not only solve the problem of water scarcity, but also provide better livelihoods for people in surrounding villages. For example, Kolar district has about 4,800 lakes and receives 600-700 mm of annual rainfall. However, last year the district received 2,100mm of rain but most of the water ran off due to the reduced water holding capacity of the lakes.

The government should prioritize watershed management programs and ensure that degritting of lakes is done across the state,” Dr. Ramachandra said.