Waterlogging and Salinity: Threats and Solutions for Productive Lands

Agriculture is the backbone of Pakistan’s economy, yet it is continuously challenged by land degradation caused by waterlogging and salinity. These two interlinked problems have silently reduced soil fertility, lowered crop yields, and rendered vast areas of land unproductive. Despite heavy investments in irrigation infrastructure, Pakistan’s agricultural lands remain vulnerable because of poor drainage, excessive irrigation practices, and inadequate soil management strategies. If unchecked, waterlogging and salinity can undermine food security, reduce farm incomes, and put national sustainability goals at risk.

This column explores the causes, impacts, and solutions of waterlogging and salinity, drawing from local and international research, while offering practical strategies that can restore land productivity and ensure sustainable agricultural practices.

Understanding Waterlogging and Salinity

• Waterlogging occurs when the groundwater table rises too close to the soil surface, saturating the root zone and preventing proper aeration. Roots suffocate in oxygen-deficient conditions, leading to poor crop growth.
• Salinity develops when excessive salts accumulate in the soil. This usually happens due to poor-quality irrigation water, inadequate drainage, or natural processes where salts rise with capillary action as groundwater evaporates.

In Pakistan, these issues are particularly severe in the Indus Basin Irrigation System (IBIS) — the world’s largest contiguous irrigation network. The over-application of canal water, seepage from unlined canals, and lack of drainage infrastructure have combined to create over 2.5 million hectares of salt-affected and waterlogged soils.

Why Waterlogging and Salinity Persist in Pakistan

1. Excessive Irrigation Practices
   Many farmers irrigate their fields based on tradition rather than scientific scheduling. Over-irrigation not only wastes scarce water resources but also raises the water table.
2. Seepage from Canals and Watercourses
   Nearly 40% of water is lost during conveyance due to unlined canals. This seepage contributes to rising groundwater levels, causing waterlogging in nearby fields.
3. Poor Drainage Infrastructure
   Pakistan has very limited functional drainage systems. Most surface and subsurface drainage schemes installed in the 1970s–90s are either poorly maintained or completely dysfunctional today.
4. Use of Saline Groundwater
   Farmers in many regions rely on groundwater for supplemental irrigation, but in arid and semi-arid zones, this water often contains high salt concentrations, which accumulate in soils over time.
5. Climate Change and Rising Temperatures
   High evaporation rates in hot climates increase the upward movement of salts from groundwater, making salinity worse.
6. Institutional and Policy Gaps
   Weak governance, insufficient extension services, and lack of farmer training on modern irrigation methods contribute to the persistence of these issues.

Impacts on Agriculture and Economy

• Reduced Crop Yields: Wheat, cotton, and rice — Pakistan’s major staples — are extremely sensitive to waterlogging and salinity. In some cases, yields drop by more than 50%.
• Decline in Soil Fertility: Salts disturb soil structure, reducing permeability and nutrient uptake.
• Loss of Arable Land: Every year, more agricultural land becomes unproductive, threatening food security.
• Economic Burden: The annual cost of productivity loss due to salinity and waterlogging is estimated in billions of rupees.
• Social Impact: Farmers in affected regions face declining incomes, forcing many to abandon agriculture or migrate to urban areas.

Technical and Practical Solutions

1. Improving Irrigation Practices

• Adopt Precision Irrigation: Techniques such as drip and sprinkler systems deliver water directly to the plant roots, reducing excess water and minimizing salt buildup.
• Laser Land Leveling: Ensures uniform water distribution, preventing ponding that leads to waterlogging.
• Irrigation Scheduling: Using soil moisture sensors or weather-based advisory services (like those under NDPAAS) helps optimize irrigation frequency and quantity.

2. Enhancing Drainage Systems

• Surface Drainage: Simple field drains or shallow ditches can help remove standing water.
• Subsurface Drainage: Installing tile drains or tube wells can lower the water table effectively in severely waterlogged areas.
• Bio-Drainage: Planting deep-rooted trees (such as eucalyptus) helps absorb excess groundwater naturally.

3. Reclamation of Saline Soils

• Leaching: Applying excess good-quality water to wash salts below the root zone (feasible in areas with good drainage).
• Soil Amendments: Applying gypsum to sodic soils improves soil structure by replacing sodium ions with calcium.
• Salt-Tolerant Crops: Introducing varieties of wheat, rice, barley, and fodders that can withstand salinity ensures some level of productivity.

4. Groundwater Quality Management

• Conjunctive Use: Mixing canal water with brackish groundwater dilutes salinity and prevents further soil degradation.
• Lining of Canals and Watercourses: Prevents seepage, reducing waterlogging risks.

5. Policy and Institutional Reforms

• Strengthening Extension Services: Farmers need regular guidance on irrigation scheduling, crop choices, and soil management.
• Integrated Water Resources Management (IWRM): Coordination between irrigation, drainage, and groundwater authorities is crucial.
• Subsidies and Incentives: Encouraging adoption of drip/sprinkler systems, gypsum application, and soil testing through targeted subsidies.

Innovative and Long-Term Solutions

• Use of Remote Sensing and GIS: Satellite monitoring can identify waterlogged and salt-affected areas for timely interventions.
• Digital Advisory Platforms: Mobile-based tools can provide farmers with real-time irrigation and soil management recommendations.
• Community-Based Drainage Management: Involving farmer organizations in maintaining field drains and watercourses ensures sustainability.
• Climate-Smart Agriculture: Promoting crop diversification, mulching, and conservation agriculture techniques to reduce vulnerability.

Conclusion

Waterlogging and salinity are two of the most serious threats to Pakistan’s agricultural productivity. They are the result of decades of inefficient irrigation, weak drainage infrastructure, and neglect of soil health. However, these challenges are not insurmountable. By adopting modern irrigation technologies, rehabilitating drainage systems, introducing salt-tolerant crops, and reforming institutional policies, Pakistan can reclaim its degraded lands and secure a more sustainable agricultural future.

Ensuring productive lands requires a shift from traditional practices to science-driven, climate-smart solutions. Every effort made today — from lining canals to training farmers — will contribute to food security, water conservation, and economic stability for generations to come.