Soils and water
Soils need more than nutrients to be healthy and to sustain plant growth, they also need water
. Water is fast becoming a scarce resource in certain regions of the world, and farmers need to be very careful in managing inputs (water and nutrients) to ensure high yields while reducing adverse effects of this management on the environment.
Soil fertility management must take water into consideration in order to be effective
. Indeed, the accumulation or depletion of nutrients in soils is directly affected by the movement of water in soils.
Here are what the three main considerations that govern the relation between water and nutrients in soil fertility management:
Managing water, nutrients and soils wisely is critical to ensure sustainable food production in a water-scarce world.
- Soil water stress will limit soil nutrient use at the plant level;
- Soil-supplied nutrients can be taken up by plants only when sufficient soil solution allows mass flow and diffusion of nutrients to roots;
- Soil water content is the single most important factor controlling the rate of many chemical and biological processes, that influence nutrient availability.
is an innovative fertilizer application method that entails applying fertilizers to crops via irrigation water
Fertigation makes it possible to “synchronize the crop’s nutrient demand with fertilizer supply throughout its growth, in effect applying the 4R principles” as the amount of fertilizer, its concentration and the timing of the application is controlled by the farmer according to the soil’s needs.
Fertigation has tremendous potential in maximising yields while minimizing environmental pollution, that could help turn vast areas of arid and semi-arid land in many parts of the world into farmland, as well as preventing water from being wasted in conventional irrigation systems.
In 2011, IFA and the International Potash Institute published a book on Fertigation, that explained the interactions between soils, water and fertilizers in fertigation, as well as “various knowledge and information on plant physiology, plant nutrition and irrigation”. It is available in IFA’s Library.