Soil acidity threatens crop yields: agriculture minister

The average acidity or alkalinity level of Bangladeshi soil, measured by pH, is currently around 4.5, which should be increased to above 6.5 to improve soil quality, Agriculture Minister Mohammed Amin Ur Rashid said today.

Excessive use of fertilisers has increased soil acidity and reduced fertility, which must be restored, he said.

The minister made the remarks at a programme organised by the Soil Resource Development Institute (SRDI) at its head office in Dhaka.

Soil pH is measured on a scale of 0 to 14 and acts as a master variable in agriculture because it determines the chemical environment of the soil, profoundly influencing nutrient availability, microbial activity and overall crop yields.

Developed countries remain covered in snow for much of the year, whereas Bangladesh produces crops throughout all 12 months. This advantage must be utilised, the minister said.

The country's soil must be rehabilitated by increasing its pH level, he said, adding that research findings on the issue should be produced within a maximum of two years.

The minister also said excessive use of pesticides beyond actual requirements is damaging the climate, degrading soil quality, harming crops and posing risks to human health.

Md Abdur Rahim, director general of the Department of Agricultural Extension, said organic matter should ideally account for around 5 percent of soil composition.

In Bangladesh, however, the average level of organic matter in soil ranges between 0.5 percent and 1.7 percent, he said.

"To achieve optimum yield capacity, at least 2 percent organic matter is required. Because of this deficiency, expected crop yields are not being achieved," he said.

"If we cannot increase organic matter content in the future, sustainable agriculture will not be possible."

"Therefore, we must focus on soil health immediately. The main reason behind this problem is the excessive use of chemical fertilisers compared to actual demand, along with insufficient application of organic fertilisers."

Previously, only one crop was cultivated on a piece of land. Now, in some cases, two, three or even four crops are grown on the same land.

As a result of this continuous cropping, the level of organic matter in the soil has declined, he said.

Soil testing has shown that farmers are applying 15 to 20 percent more chemical fertilisers than required, although growers are becoming increasingly aware of the issue, he added.

ASM Golam Hafeez, professor of agricultural finance and banking at Bangladesh Agricultural University, said that if the soil is not healthy, people cannot remain healthy either.

"If soil health does not improve in the coming days, there is a risk of malnutrition. We must begin addressing this problem now," he said.

Md Afsar Ali, director general of the SRDI, also spoke at the event.