Harnessing green manuring for nature-based sustainable soil management in Bangladesh  

A farmer in his green manure field in Rangpur, Bangladesh. (Photo credit: Bappy Kumar, IRRI)

By Sharif Ahmed, Abdullah Miajy, Manik Debnath, and Humnath Bhandari

Did you know that most agricultural soils in Bangladesh are low in organic matter, with levels less than 1–2%? This is below the ideal range of 3–5% required for soil fertility. The main reasons for low soil fertility in Bangladeshi soils include continuous cropping without adequate nutrient replenishment, overuse of chemical fertilizers, less crop diversification, complete crop residue removal practices, and inadequate organic matter additions.

Soil fertility is the cornerstone of productive agriculture, yet modern farming practices increasingly threaten its health. Agriculture is the backbone of the Bangladesh economy, and sustainable crop production largely depends on soil health conditions. Organic matter is considered the life of soil because it serves as a reservoir of microorganisms and source of nutrients such as nitrogen, phosphorus, sulfur, and micronutrients. The beneficiary microorganisms of soil, which can help decompose plant foods from inorganic and organic sources, can’t survive in soil without organic matter. Moreover, organic matter acts as a binding agent, promoting the formation of stable soil aggregates and improving porosity, aeration, and root penetration. It also increases the soil’s cation exchange capacity, helping nutrients remain available rather than leach away. In addition to soil fertility and physical improvement, organic matter helps in the sequestration of carbon in soil to mitigate greenhouse gas emissions.

Because of the low organic matter in Bangladeshi soil, farmers often use excessive chemical fertilizers in their fields. This results in a significant amount of chemical fertilizers being applied in crop production, most of which are imported. According to the Ministry of Agriculture in Bangladesh, the annual demand for chemical fertilizers in the country for the most recent fiscal year is approximately 5.95 million tons. This includes 2.70 million tons of Urea, 1.60 million tons of Diammonium Phosphate (DAP), 0.75 million tons of Triple Super Phosphate (TSP), and 0.90 million tons of Muriate of Potash (MOP). Around 80% of the country’s fertilizer needs are met through imports, with limited domestic production amounting to around 1 million tons of urea and only 100,000 tons each of TSP and DAP. The government of Bangladesh typically allocates a significant portion of the national subsidy budget—approximately US$ 2500-3000 million to keep fertilizers affordable for agricultural crop production in the country.

Bangladesh currently provides substantial subsidies on chemical fertilizers to support farmers and ensure food security. However, these subsidies are expected to be gradually reduced in the future, which could significantly impact farmers by increasing input costs and potentially decreasing fertilizer use.  The imminent removal of fertilizer subsidies could drive up prices, challenge smallholders’ livelihoods and productivity, and lead to lower crop yields, thereby hampering overall agricultural productivity.

To address these challenges sustainably, promoting nature-based solutions like green manuring becomes essential. Green manuring involves growing cover crops to enrich soil fertility naturally, reducing dependence on chemical inputs, and protecting the environment. Such eco-friendly practices can help farmers adapt to subsidy reductions while ensuring sustainable and productive agriculture.