Fertilizers and Water Holding Capacity: Key to Mitigating Droughts
Updated: May 8
Recently, a leading Dutch newspaper NRC published an article ''Hardly has spring started and a significant portion of European land is already parched''. This article was echood by a similar article from the BBC. Is drought getting worse in Europe, the US and on other places around the globe?
According to the European Drought Observatory, 23.0% of the EU-27 territory is in Warning conditions and 2.2% is in Alert conditions. Therefore, regenerative agricultural practices are increasingly becoming important. One such practice involves the responsible use of fertilizers.
In this blogpost, we'll explore how the use of fertilizers impacts the water holding capacity of soil, a crucial factor in mitigating drought, and the role of regenerative agriculture.
Photo by nishihata
How do synthetic fertilizers worsen the impact of drought?
While synthetic fertilizers can boost crop yields, their overuse can have negative consequences on soil health and water retention.
Here are 3 reasons why synthetic fertilizers exacerbate water requirements and impact drought.
1. Synthetic fertilizers require lots of water to convert.
Did you know that the most inefficient form of nitrogen for plants is nitrate? It costs a lot of energy to convert it into amino acids, which are essential for growth, and requires a lot of water. For every molecule of nitrate to convert to peptide, plants need three molecules of water. However, when the soil has a robust ecosystem of soil bacteria, the bacteria can convert atmospheric nitrogen into bacterial nitrogen, which can be easily used by plants to produce amino acids. This means that the plants do not need to rely on nitrate as much, which in turn reduces their water requirement by 30% compared to when they rely on nitrate as the primary source of nitrogen.
What other elements of synthetic fertilizer require water to convert?
Synthetic fertilizers are typically composed of different elements that all require water to some extent to be taken up by plants.
Phosphorus is an essential nutrient for plant growth, but it needs to be in a soluble form to be taken up by roots. When synthetic phosphorus fertilizers are applied to soil, they dissolve in water and can form insoluble compounds with soil minerals. This means that plants may not be able to access the phosphorus unless there is enough water in the soil to dissolve the fertilizer and make it available to plants.
Similarly, potassium is also essential for plant growth, and it is taken up by roots in a dissolved form. Therefore, synthetic potassium fertilizers need to dissolve in water to become available to plants.
2. Decline in Organic Matter:
The overuse of synthetic fertilizers may leads to a decrease in organic matter, which is crucial for water retention. Healthier soil, rich in organic matter, can hold up to 20 times its weight in water.
How does synthetic fertilizers contribute to a decrease in organic matter, which is crucial for water retention?
Synthetic fertilizers can lead to a decrease in organic matter in soil, which is crucial for water retention, for several reasons:
Synthetic fertilizers provide nutrients to plants in a form that is readily available, which means that plants can take up nutrients without the need for soil microorganisms to break down organic matter. As a result, the microbial activity in soil can decrease, and the organic matter can be depleted over time.
Synthetic fertilizers can also alter the soil's pH level, making it more acidic. This can affect the activity of soil microorganisms and decrease the rate at which organic matter is broken down, which can lead to a decline in soil organic matter content.
Synthetic fertilizers can contribute to soil erosion, which can further deplete soil organic matter. This is because organic matter helps to bind soil particles together, reducing the risk of erosion.
The decrease in organic matter in soil can have significant consequences for water retention. Organic matter acts as a sponge, holding onto water and releasing it slowly to plants over time. When organic matter is depleted, the soil can become less porous and less able to hold onto water. This means that water can run off more easily, leading to soil erosion, and plants may not be able to access the water they need for growth.
Therefore, sustainable soil management practices that prioritize soil health and organic matter content, such as regenerative agriculture, are essential to maintain water retention and ensure the long-term sustainability of agriculture.
3. Degradation of Soil Microbial Activity:
Excessive synthetic fertilizer application can disrupt the soil's microbial balance, reducing the overall health of the soil and its capacity to withstand drought conditions.
Why does synthetic fertilizer application disrupt the soil's microbial balance?
Synthetic fertilizer application can disrupt the soil's microbial balance for several reasons:
Synthetic fertilizers contain high levels of readily available nutrients, such as nitrogen, phosphorus, and potassium. When these nutrients are applied in large amounts, they can create a temporary "feast" for soil microorganisms, leading to a rapid increase in microbial populations. However, this burst of activity can quickly deplete the available nutrients, leading to a decline in microbial activity over time.
Synthetic fertilizers can also lead to changes in the soil's pH level. Many soil microorganisms thrive in a neutral or slightly acidic pH range, and synthetic fertilizers can make the soil more alkaline. This can reduce the activity of some beneficial microorganisms, leading to imbalances in the soil microbial community.
Synthetic fertilizers can harm soil organisms directly. For example, some synthetic fertilizers contain high levels of salt, which can harm or kill beneficial soil organisms. Overuse of synthetic fertilizers can also create a toxic environment for soil organisms, reducing their activity and diversity.
When the balance of soil microorganisms is disrupted, it can have negative impacts on soil health, such as reduced nutrient cycling, lower organic matter content, and decreased soil water-holding capacity. This can ultimately lead to reduced crop yields and degraded soil quality.
Therefore, sustainable soil management practices that prioritize soil health, such as reducing synthetic fertilizer use and increasing organic matter content, are essential to promote a healthy soil microbial community and ensure the long-term sustainability of agriculture.
🌱 Organic Fertilizers:
Organic fertilizers, derived from plant and animal sources, imrpove soilhealth and the water holding capacity:
1. Enhanced Soil Structure: Organic fertilizers improve soil structure by promoting the formation of aggregates, which in turn, enhance water holding and infiltration.
2. Increased Organic Matter Organic fertilizers contribute to the soil's organic matter content, improving its ability to hold moisture and providing a buffer against drought.
Why do Organic Fertilizers contribute to Soil Organic Matter?
Organic fertilizers contribute to the soil's organic matter content because they are derived from organic materials, such as plant or animal waste, which contain carbon and other organic compounds. When organic fertilizers are applied to soil, they provide a food source for soil microorganisms, such as bacteria and fungi, which break down the organic materials and release nutrients in a slow, steady manner. As the microorganisms consume the organic materials, they release carbon dioxide back into the atmosphere and leave behind organic matter in the soil. Over time, the accumulation of organic matter can improve soil structure, increase water-holding capacity, and promote healthy soil microbial communities. Organic matter acts like a sponge, holding onto water and releasing it slowly to plants over time. This can help soils better withstand drought conditions by retaining more water in the soil. In addition, organic fertilizers can also help improve soil health and fertility in other ways. For example, they can promote beneficial soil microbial activity, reduce soil erosion, and improve nutrient cycling.
3. Improved Soil Microbial Activity: Organic fertilizers promote a diverse and healthy microbial community in the soil, which aids in nutrient cycling and enhances the soil's resilience to drought.
Regenerative Agriculture improves drought resilience
Regenerative agriculture offers a promising solution to the challenges of drought. By improving the water-holding capacity of soils, reducing the need for synthetic fertilizers that exacerbate the impact of drought, and increasing the resilience of crops to water stress, regenerative agriculture can help build a more sustainable and resilient food system for the future.
Use Soilbeat to for successful drought mitigation
Consider SoilBeat to integrate optimized Fertilizer Management. With our software, you can easily determine the appropriate type and quantity of fertilizers for a specific crop. No longer guess what works on your land, and save money while improving your crop yields. How do you do that?
By easily monitoring the effect closely with soil and plant sap tests over time in our dashboards.
Easy direct communication with your agronomist via our platform to bring your Fertilizer Management to a next level.
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Do you want to know more about drought management, organic matter, regenerative agriculture and water retention? Continue reading through the resources below:
BBC - Guy Hedgecoe: Climate change: Catalonia in grip of worst drought in decades
NRDC: Expert blog on how Organic Matter Can Improve Your Soil's Water Holding Capacity
Noble Research Institute: Prepare for Drought With Regenerative Ag Mindset
Metabolic: Regenerative agriculture: Farming in nature's form