Best of both worlds: Application of organic fertilisers (black granules on the soil) and chemical fertilisers (supplied via drip irrigation) for a well-balanced nutrient diet for the plants. Photo: Tan Ngai Paing
Plants need nutrients to grow and flourish. In total, 17 essential nutrient elements are required for a plant’s life cycle.
Among them, elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) are required in larger quantities, whereas others such as boron (B), zinc (Zn), iron (Fe), and copper (Cu), are needed in smaller amounts.
These nutrients, typically found in the soil, are taken up by the plant roots and used throughout the plant.
However, nutrients in soils have increasingly been depleted due to agricultural practices to meet the ever-increasing demand for food and fibre.
Soils can only naturally supply a limited quantity of nutrients before becoming barren.
Fertilisers can be used to address this issue, but the following questions arise: “Organic or chemical fertilisers?”, “Which is better?” and “What are their differences?”
Chemical fertilisers, derived from chemical reactions or industrial processes, provide readily available nutrients to plants in concentrated forms.
They can be tailored to specific nutrient ratios to suit plants’ needs at different growth stages, which facilitates swifter growth and higher yields in plants.
And because chemical fertilisers are faster-acting and allow for more precise control of nutrient levels, they can actually be cheaper on a per nutrient basis than organic fertilisers.
Chemical fertilisers are also easier to handle, store and apply than organic fertilisers.
However, if used improperly, chemical fertilisers can cause nutrient runoff and leaching, contaminating nearby water bodies.
Over time, over-applications can lead to the build-up of excess nutrients in the soil, which would damage plant roots and decrease soil fertility; and in the water bodies, which would contaminate our water source and harm aquatic flora and fauna.
Organic fertilisers, derived from natural sources like plants or animals, also provide essential plant nutrients and promote soil health.
They contribute to improved soil structure and better root growth by supporting soil microbial activity and retaining soil moisture.
In contrast to chemical fertilisers, organic fertilisers release their nutrients slower and more gradually, minimising nutrient runoff and leaching; thus, they are more environmentally friendly.
And because they are not as concentrated as chemical fertilisers, using organic fertilisers carry less risk of chemical burns to plants.
Moreover, organic fertilisers can be created from organic waste materials, promoting reuse and recycling for increased sustainability.
However, organic fertilisers are often required in larger quantities to deliver the same amount of nutrients as chemical fertilisers.
This is due to the lower nutrient content and much slower-release nature of organic fertilisers that would necessitate larger quantities and longer time frames to meet the plant’s nutrient demands. This in turn could lead to lower crop yields.
And if not properly treated or composted, organic fertilisers made from organic waste materials might contain harmful pathogens or weed seeds.
Despite their respective limitations, both types of fertilisers play vital roles in crop production. A balanced use of both organic and chemical fertilisers can benefit soil health and plant growth more than using either one alone.
Organic fertilisers improve soil health, enhancing its physical, chemical and biological aspects, leading to better soil structure with more pores for aeration and moisture. Young plants can thrive easily in such well-conditioned soils.
In contrast, chemical fertilisers can be tailored to cater to the nutrient demand of different growth stages of plants, helping farmers achieve an impressive harvest.
However, we must consider the potential negative impacts of both fertilisers. Over-reliance on organic fertilisers could lead to challenges due to their variable composition and relatively slower nutrient release.
And misuse of chemical fertilisers can cause environmental issues and create nutrient imbalances.
One common gardening mistake is to overuse fertilisers.
Impatient gardeners often “experiment” with various fertilisers and their combinations in rapid succession, hoping to find an ideal fertiliser for their plants.
This practice can be damaging, as excessive fertilisers can lead to nutrient imbalance and toxicity that can be difficult to correct.
With the increasing degradation of soils worldwide due to agricultural activities, we need to restore soil health by replenishing depleted nutrients.
The judicious use of both organic and chemical fertilisers can complement each other in achieving this goal.
Our responsibility is to ensure these resources are used thoughtfully, maintaining a balance that benefits both crop production and the environment.
Dr Tan Ngai Paing is a senior lecturer at the Dept of Land Management, Faculty of Agriculture, Universiti Putra Malaysia. His field of expertise is in soil chemistry. The views expressed here are entirely his own.
