KATHMANDU – The acidification of soil in Nepal’s agricultural land has been growing every day.
After conducting tests of the soil and its fertility level at various labs, the Soil Management Directorate has reached a conclusion that the soil of Nepal’s agricultural land has become acidic.
Senior soil expert Dr Janardan Khadka said the soil’s fertility has been declining day by day because of the growing acidity of soil. “The direct effect of the growing acidification can be seen in the crops, and nutrients of the plants,” said Khadka, who is also the information of the directorate.
According to him, soil pH value is a measure acidity of alkalinity of the soil and if the pH value decreases from 7 to 0, the soil can be considered becoming acidic. Mostly, the soil having the pH value from 5.5 to 7.5 are said to be appropriate for agriculture. Statistics of lab tests indicate that Nepal’s soil is becoming acidic as the pH value has been found to be declining.
A pH value of any substance is a measure of hydrogen ion concentration. The pH value of the soil will determine its acidic, alkaline, or neutral property.
The pH value will range from 0 to 14 and the pH value 7 is considered neutral—neither acidic nor alkaline. The tests conducted at Soil Management Directorate and the laboratories under it in the fiscal year 2069/2070 showed that 13.33 percent of the soil was acidic, 65.77 percent soil was slightly acidic and 16.44 percent soil was neutral.
In the fiscal year 2070/71, lab tests 53 percent of soil was found acidic and 33.51 percent of soil was found neutral. Similarly, lab test data in the fiscal year 2073/074 showed that 60 percent of the soil was acidic.
Khadka attributed the growing acidification of soil to the excessive use of chemical fertilizers and pesticides by the farmers to increase crop productivity in one season.
“In order to increase the crop yield, it is necessary to balance acidity, alkaline of the soil and to use proper amount of nitrogen, phosphorous, potassium, and organic elements. “But the tests have shown that the acidity of the soil is growing in comparison to past years,” he said. “The urea and Di-ammonium phosphate have been overly used in the soil. The declining use of organic fertilizer has resulted in the growth of acidity.”
He says the use of organic fertilizer has been falling sharply and the use of chemical fertilizer has been growing rapidly in the Terai region. “The increasing acidity of soil is the biggest problem. This has affected the crop yield,” he said. “Plants can’t take the nutrients necessary for it, thereby affecting its healthy growth.”
Khadka blames the tendency to not use necessary amount of fertilizers and to cultivate the crops with high yield potentials for the growth in acidity of soil. He adds that, similarly, lack of fertilizer management based on Intensive Crop Farming, decline of cattle farming, forest firing and deforestation will increase soil acidity, thereby decreasing fertility.
What else to do next?
Khadka says the soil acidity can be reduced by using agricultural limestone powder and prioritizing organic fertilizer over chemical. “Farmers should test the soil and use necessary amount of limestone,” he said.
He further informed that the use of limestone increases the soil fertility through microscopic and molecular-level activities and helps in stabilizing the nitrogen level in atmosphere. Khadka advises to use limestone in soil because it will help in adding necessary nutrients for the plants such as calcium and magnesium and removes the toxic effect of aluminum, manganese and iron, while increasing the availability of phosphorous.
