Restoring soil health in Nepal requires a multi-faceted approach, including erosion control measures, balanced fertiliser use, organic amendments and public awareness campaigns along with better education for farmers
Soil is more than just dirt beneath our feet-it is a living, breathing system that nurtures life itself. It grows the food we eat, filters the water we drink, stores carbon to combat climate change and supports countless forms of life, from tiny microbes to towering trees. Even the nutrients in our meat and dairy trace their origins back to plants that draw their life-giving sustenance from soil.
Yet, this vital resource is under threat from erosion, pollution, and unsustainable farming. About 33 per cent of the world's soils are degraded, according to the United Nations Food and Agriculture Organisation (UNFAO), posing dreadful consequences for food security and environmental health. The 2024 World Soil Day (celebrated December 5) theme, "Soil Care: Measure, Monitor, and Manage" reminds us that healthy soils are key to a sustainable future.
When you visit a medical doctor, you will be subjected to various health indicators such as temperature, blood pressure and pulse rate. These measurements help assess your overall health. Similarly, the soil health is evaluated through various indicators. Based on these, the UNFAO Intergovernmental Technical Panel on Soils has identified 10 major global threats to soil, including processes like soil erosion, changes in soil organic carbon and nutrient imbalances.
Just as addressing health issues early is key to staying healthy, initiative-taking measures to reduce these threats are essential to prevent further soil degradation. For instance, in Nepal, these challenges-soil erosion, nutrient imbalance and pollution-are growing problems, highlighting the need for urgent action to protect and restore soil health.
Soil erosion, a leading cause behind deteriorating soil fertility or land productivity, is exacerbated by slope failures, landslides, debris flows, bank erosion and deforestation. This process removes the upper crust of soil, or the fertile topsoil, from one place and deposits it at a new site, which can take 30 years to regenerate a single inch.
Assuming a few hours of heavy rainfall (about 50 mm) in Nepal's tarai region on exposed soil can wash away approximately 300 grams per kattha in a single event. Soil loss from agricultural land leads to decrease in crop production, damage to drainage networks and degradation of water quality, often leading to eutrophication in freshwater bodies.
When soil erosion is severe, soil erodes faster than it can be renewed. In Nepal 369 million metric tons of soil are washed away annually. Soil loss in the Koshi basin reaches up to 22 tons per hectare annually on barren lands.
Though the national average use of chemical fertilisers in Nepal has increased significantly from 16.7 kg per hectare in 2002 to 97.8 kg per hectare in 2021, farmers still face challenges with their management. This includes the 4Rs of nutrient stewardship (right source, right rate, right time, right place), hindered by a lack of awareness and reliance on outdated practices. Additionally, traditionally used organic fertilisers are receiving less attention, disrupting balanced nutrient cycling in farming systems.
The overuse of nitrogen fertilisers, such as urea, has resulted in widespread soil acidity, affecting 40 per cent of agricultural land and reducing crop productivity in Nepal. Fertiliser recommendations remain outdated, failing to account for diverse farming conditions, leading to inefficiencies and nutrient imbalances. Despite the recognised need for site-specific fertiliser application based on soil testing, a unified soil health card programme is lacking in extension services and public institutions.
Terrestrial soils are widely polluted by microplastic, which are plastic fragments with a diameter of less than 5 mm, or about the size of a pencil eraser. Studies show that up to 2.1 kilos of microplastics per kattha are present in fertile soils. These tiny particles harm earthworms and soil microbes, reducing their activity by 30 to 50 per cent, and bind harmful chemicals, worsening toxicity.
A study conducted in Phewa Lake in 2021 revealed that the concentration of microplastics in the surface water was higher in winter at about 3 particles per liter, compared to the rainy season. Pesticides and heavy metals amplified by microplastics affect crops and food safety. Alarmingly, humans unknowingly consume about 50,000 particles annually when eating plastic-contaminated food. For these reasons, microplastic pollution was recognised as one of the top 10 environmental threats by the United Nations Environment Programme.
Despite the many issues present in Nepali soil, such as nutrient runoff, organic matter loss and soil compaction, the good news is that soil degradation is reversible. By following the principles of measure, monitor and manage, we can restore soil health.
Restoring soil health in Nepal requires a multi-faceted approach, including erosion control measures, balanced fertiliser use, organic amendments and public awareness campaigns along with better education for farmers. To ensure sustainability, soil health indicators should guide actions, much like health metrics in humans. Accessible soil testing and site-specific recommendations will help farmers optimise their practices.
Integrated soil fertility management – combining organic and inorganic inputs –is vital for nutrient cycling. Policymakers must ensure timely access to quality fertilisers and introduce programmes addressing soil acidity and pollution. Public awareness campaigns about the importance of soil health for food security and environmental sustainability can create a culture of soil care. When we view soil as a living system, it becomes our shared responsibility to nurture and protect it.
Panday, Ph.D, is a soil scientist