Understanding water quality helps protect crops: Experts
Continuous use of saline water for irrigation results in the buildup of salts in the soil, which negatively impacts soil health and gradually decreases crop yields. Therefore, it is crucial for farmers to test tubewell water before using it for irrigation. Testing helps identify potential problems that could damage crops, degrade soil quality or affect the irrigation system. By understanding the water’s properties, farmers can make informed decisions about its suitability for irrigation and adopt appropriate management practices to reduce any harmful effects.
According to a report, in about 40 per cent of the total area of Punjab, especially in the south-western districts, the underground tubewell waters contain high salt concentrations. This water is either saline (containing chlorides and sulphates of sodium) or sodic (containing carbonates and bicarbonates of sodium). Water in many areas may also contain toxic elements like boron and fluoride.
Therefore, it is essential to conduct tests on tubewell water before using it for irrigation, said Fatehjeet Singh Sekhon from Punjab Agricultural University’s (PAU) Krishi Vigyan Kendra. Knowing the kind and extent of the problem of water contamination helps in adopting specific management practices to mitigate its harmful effects on soil fertility and crop productivity, he added.
In regions where irrigation water quality is subpar, it is crucial to leach out excess soluble salts and water from the root zone of the soil to maintain a favourable balance of salt and water, says Vivek Kumar, another expert from PAU.
“In areas with inadequate drainage and soils containing hard pans at certain depths, long-term irrigation with poor quality water leads to a quicker accumulation of salts in the soil compared to well-drained soil conditions. Therefore, ensuring proper drainage is essential when utilising poor quality water for irrigation,” added Kumar.
Adding further, Karamjit Sharma from KVK said to achieve uniform distribution of irrigation water across the field, it is essential to properly level the land. Adequate land levelling also guarantees consistent leaching of soluble salts and water from the soil. Even minor variations in micro-relief within the field can lead to uneven distribution of water and salts.
“It is always preferable to grow crops and varieties capable of producing high yields even when irrigated with saline or sodic waters. Only salt-tolerant and semi-tolerant crops like barley, wheat, mustard, guar, senji, spinach, turnip, sugar beet, raya, and millets should be grown. Pulse crops are sensitive to salinity and sodicity and, therefore, should not be irrigated with poor quality waters,” Sharma said.
Water in village ponds contains essential plant nutrients. However, it may also contain salts such as carbonates, bicarbonates and chlorides of calcium, magnesium and sodium in undesirable amounts. Therefore, water should be tested at the Soil and Water Testing Laboratory and used for irrigation as per recommendations, said the experts.
