Our previous article explored how to address the food crisis, noting that soil degradation is a key driver of the crisis. Today, we will focus on soil issues and explore in detail how to effectively address soil degradation.
▪ Approximately 33% of the world’s soils are degraded (FAO data), reducing their water storage capacity and expanding drought-susceptible areas.
▪ This decline in soil water retention directly exacerbates agricultural production instability: a 10% decrease in soil moisture can lead to a more than 20% reduction in crop yields (for example, corn and wheat).
▪ By 2050, global agricultural production will need to increase by 60% to meet demand, but soil degradation could reduce available arable land by 50%.
Soil is a critical, non-renewable, and irreplaceable resource. Good soil condition is crucial for economic development, social security, and the environment. Soil plays a vital role in the cycles of nutrients, carbon, and water. In turn, an adequate supply of water in the soil determines the normal growth of plants and their ability to withstand drought. Proper moisture retention ensures a continuous supply of water to plants, which is essential for nutrient absorption and overall health.
How can soil water retention be improved?
This can be achieved primarily through physical methods (improving soil structure and reducing evaporation) and chemical methods (water-retaining agents and soil conditioners).
Physical Methods (Principle: By changing the soil’s physical structure or environmental conditions, reducing evaporation and water loss, thereby increasing water retention):
1.Surface mulch: Straw/hay, biodegradable mulch films, and living mulch can reduce evaporation by 30%-50%. They regulate soil temperature and suppress weeds.
2.Deep tillage and deep plowing: Using a deep tiller to break up the plow base (30-50 cm deep) promotes root penetration and utilizes deep moisture. This improves soil aeration and reduces surface runoff.
Chemical Water Retention Methods (Principle: Chemical materials absorb or lock in water, or improve soil colloidal properties to enhance water retention).
1.Water-retaining agents: Through a “water absorption-storage-release” mechanism, they significantly improve soil moisture conditions, alleviate drought stress, and promote plant growth. Water-retaining agents can absorb 200 to 1000 times the volume of pure water, with the majority of this absorbed water being available for plant use. By improving soil structure and enhancing its water and fertilizer retention capacity, they promote plant growth and increase biomass.
Recommended products: Sodium polyacrylate (PAA), polyacrylamide (PAM),PolyGlutamic Acid (γ-PGA).
2.Soil conditioners: Improve water retention through multiple approaches, including optimizing pore structure, enhancing colloidal adsorption, and regulating biological activity.
Recommended products: Compost, bentonite, SAP (polyacrylamide), humic acid, and microbial agents.
Conclusion: Soil water retention plays a vital role in agricultural production, directly impacting crop growth, yield, and sustainable agricultural development. It is a key lever for agriculture to address food insecurity.