How soil moisture sensors can help irrigation in summer

Bengaluru: With an alarming depletion of the groundwater table this summer, the agricultural industry faces a greater burden of adapting to environmental changes. 

While protected cultivation techniques such as hydroponics limit water wastage, it is often a matter of economy and affordability at the disposal of a conventional farmer. 

Gaurav Narang, the CEO of CityGreens, a hydroponics startup in Bengaluru, told DH: "Employing hydroponics nearly saves 85% of water, compared to traditional farming. The only loss takes place in transpiration and evaporation." 

He, however, acknowledged that the basic limitation of hydroponics is its dependence on external structure. 

Key challenge

In conventional farming, irrigation comes across as a primary challenge, particularly taking into account water shortage in the summer. 

Dr S V Suresh, Vice Chancellor of the University of Agricultural Sciences, Bengaluru, suggested that preserving soil moisture is important in the summer where the water content in the soil evaporates quicker than the rest of the year. 

"Irrigation of any sort requires a certain amount of availability of water. In dire situations, we advise mulching. The organic matter in the soil, be it the dried leaves or the fallen fruits, must be left out," he said.  He added that it not only acts as a coating to the soil, reducing evaporation of soil moisture but also enhances the infiltration of water into it during monsoon. 

Dr D C Hanumanthappa, a senior scientist at the university, recommends the use of soil moisture sensors to detect the water content in the soil to make informed decisions about irrigation. 

"Irrigating only after spotting wilted crops requires a higher amount of water to ensure that the plants do not die. With the use of soil moisture indicators, a farmer can easily see the amount of moisture in the soil and water the plants accordingly. Ideally, when the crops are watered at 50% depletion of soil moisture in the root zone, farmers can save up to 20% of water,” he said. 

Speaking about mulching as a water-conserving technique in farming, he said mulching alone could save 20-28% of water. 

While allowing leaves and fruits to decay in the soil reduces the evaporation of water content, plastic mulching is also popular among tomato and chilli cultivation, he said. 

He added that micro-irrigation techniques such as the use of sprinklers and drip irrigation are most effective in saving water.