Mr Pachori recommends that one-third of the nitrogen requirement should come from organic material in the form of farmyard manure and compost. Three-fourth of the nitrogen requirement should be met by fertilisers – either urea or ammonium sulphate or DAP (Diammonium Phosphate).<\/p>\n

However, as Dr Pachori said, farmers are using DAP more than required.<\/p>\n

On average, eight in 10 samples in the three states had non-optimal potassium in the soil.<\/p>\n

Nearly one-third of the soil samples in Tamil Nadu have non-optimal phosphorus. Four in 10 soil samples in Gujarat and one in 10 in Rajasthan had non-optimal phosphorus.<\/p>\n

“States using more water for irrigation give higher yields and take up more nutrients from the soil,” explains Dr Ashok Kumar Patra, 2022 Glinka World Soil Prize winner. “But if farmers don’t add an equal amount of nutrients to the soil, there will be a nutrient deficiency,” adds Dr Patra, an Emeritus Scientist & Former Director of ICAR-Indian Institute of Soil Science, Bhopal.<\/p>\n

Excessive irrigation can lead to loss of nutrients from the soil, leaving it less fertile.<\/p>\n\n

Since the soil in his field has a light texture, Kala Khan, a farmer residing in the Alwar district of Rajasthan has applied fertiliser like DAP and urea to fulfill the phosphorus and nitrogen requirements. Fellow farmer Bijendra Kumar often adds more urea to compensate for the water shortfall.<\/p>\n

“A rise in the quantity of phosphorous results in micronutrient (zinc and iron) deficiency in soil. Phosphorous and zinc and iron have an antagonistic effect,” Dr Pachori said.<\/p>\n

Excessive DAP dries up the soil, reduces water-holding capacity, makes soil alkaline and destroys micro-organisms and bacteria in the soil, added SP Yadav, Agriculture Research Officer, Soil Testing Laboratory, Alwar, Rajasthan.<\/p>\n

The three top water-intensive crop growing states have mixed results. In Rajasthan, over half of the soil samples showed deficiencies in both iron and zinc, while 8 per cent also displayed a lack of sulphur.<\/p>\n

On the other hand, in Gujarat, one-fifth of the soil samples were found deficient in sulphur. 29 per cent of the soil samples had iron deficiency while 37 per cent had zinc deficiency.<\/p>\n

One-third of the soil samples in Tamil Nadu reported sulphur deficiency. 40-45 per cent of the sample had iron and zinc deficiency, as per the Soil Health Card 2023-24.<\/p>\n\n

Five years ago, Rajasthan’s soil was more deficient in zinc. Now it is iron deficient. “It is because our department supplies zinc. Farmers too shell out some money and buy zinc supplements,” said Mr Yadav.<\/p>\n

The consequences of poor soil on plant health<\/strong><\/p>\n

Lack of soil nutrients directly impacts plant growth – both in terms of quality and quantity. Micronutrients iron and zinc act as catalysts and support various metabolic activities. “Iron and zinc deficiency in soil can lead to retarded growth, less production, and low quality of produce,” said Ajai Pachori, Joint Director, Agriculture (Chemistry), Government of Rajasthan.<\/p>\n

Zinc also helps plants in an uptake of nutrients like calcium and chlorophyll formation.<\/p>\n

Sulphur, another micronutrient, aids in the growth of oilseeds and pulses. Sulphur deficiency in the soil can lead to protein deficiency in pulses, said SP Yadav.<\/p>\n

“Let’s say you grow pulses on soil lacking sulphur. The harvested crop will look like a regular pulse; when cooked, it will appear and taste like any other. However, it won’t meet your protein needs, as the sulphur deficiency in the soil has caused it to lack essential protein,” he explained.<\/p>\n

Nitrogen, a macronutrient, plays a key role in plant germination. “The plant’s body, which develops from the seed, is composed of nitrogen. The main role of nitrogen is to increase greenery, and plant growth,” adds Mr Yadav.<\/p>\n

Phosphorus, a co-macronutrient, helps develop roots and grain formation.<\/p>\n

The job of potassium is to increase production quality and protect crops from diseases and pests.<\/p>\n

“Soil health manifests directly with micronutrient deficiencies within the food items, which could be cereals, pulses, fruits and vegetables, etc,” explains Dr Rajiv Tandon, Consultant Paediatrician and Executive Director, The Health Continuum. He adds, “And that eventually leads to the same low levels of minerals and vitamins in the people who eat that particular food item.”<\/p>\n

Restoring soil health<\/strong><\/p>\n

The bottom line is that states growing water-intensive crops have bad soil health. Thirsty crops take up more nutrients than less thirsty crops and vice versa. Therefore, sustainable farming practices play a vital role in maintaining and improving soil health.<\/p>\n

Farmers are being taught to use fertilisers judiciously and apply farmyard manure to maintain soil health. Mr Yadav explained, “Farmers often have livestock, but don’t utilize their manure effectively. Typically, it’s spread on the soil, where it’s exposed to pollution and extreme heat, causing it to dry out. When it rains, the nutrients are washed away, and the manure doesn’t decompose properly, limiting its potential benefits. However, by digging a pit to store the manure, soil retains moisture throughout the year. Microorganisms can break it down more efficiently, transforming it into valuable vermicompost. This process enhances the soil’s physical, chemical, and biological properties.”<\/p>\n