The harmful effects of chemical fertilizers

How to reduce the effects of harmful chemical fertilisers

Chemical fertilisers have long been relied upon by farmers to boost crop yields. However, their excessive use has led to environmental pollution, increased costs, and a dependency on external inputs. The cost of fertilisers has also surged significantly, with prices more than tripling in certain cases. This rise can be attributed, in part, to the escalating fuel prices following the economic recovery from the Covid-19 shock and the war in Ukraine. As a result of these price increases, farmers are facing severe repercussions, and consumers are bearing the brunt of higher food prices. These price increases have exacerbated the global food crisis, with millions of people facing acute hunger or food shortages. In addition, the climate crisis has triggered extreme weather events such as heatwaves, droughts, and floods in crucial agricultural regions worldwide, causing further damage to harvests. 

It is clear that reducing reliance on chemical fertilisers is not only economically beneficial, but also crucial for mitigating environmental impacts.

It’s often assumed that fertiliser use and crop yields present an unavoidable trade-off. To increase yields, you need more and more (and more) fertiliser. But studies suggest that this trade-off is not always as extreme as we may think.

What the science says

Scientists have conducted studies to address issues related to the use of synthetic fertilisers in agriculture. Their research aims to identify climate-friendly practices that can reduce reliance on chemical fertilisers while maintaining high yields. They’ve found that by adopting sustainable and regenerative farming methods, farmers can improve ecosystem health, mitigate economic shocks, and promote a fairer distribution of fertilisers, all without compromising food production.

In a recent publication in the peer-reviewed journal Nature Sustainability, researchers highlighted the benefits of reducing dependence on chemical fertilisers. This reduction would help buffer farmers and consumers against economic shocks, such as the current surge in fertiliser costs and subsequent increase in food prices. Additionally, widespread adoption of these practices could lead to a more equitable global distribution of fertiliser. The study analysed 30 long-running experiments conducted on farms in Europe and Africa, each lasting over nine years. The researchers assessed how natural farming methods could enhance crop yields. The data encompassed over 25,000 harvests across six crops: wheat, maize, oat, barley, sugar beet, and potatoes.

Key findings from the study include:

  • Sustainable farming techniques did not increase yields when used alongside high fertiliser applications. However, the highest yields were achieved when sustainable practices were combined with some nitrogen additions to the soil.
  • Adding animal manure to the soil proved more effective in boosting yields compared to plant-based compost or cuttings.
  • Cultivating a variety of crops helped suppress weed growth and disease incidence.
  • Growing legumes such as beans and clover had the added benefit of improving soil fertility by adding nitrogen.

Another one of the world’s largest and most impressive studies shows us that simple interventions can produce significant results. From 2005 to 2015, researchers worked with 21 million smallholder farmers  across China to see if they could increase crop yields while also reducing the environmental impacts of farming, and they were successful! Average yields of maize, rice and wheat increased by around 11%, while nitrogen fertiliser use decreased by around one-sixth. By producing more crops and using less fertiliser, this experiment provided an economic return of US$12.2 billion—just by educating and training farmers on good management practices.

The impact of regenerative farming techniques 

The use of sustainable farming techniques, such as adding manure and compost to soils, growing nitrogen-fixing plants between crops, and cultivating a diverse range of produce, has been shown to increase yields while protecting and improving natural ecosystems. Long-term experiments conducted in Europe and Africa demonstrated that these practices could replace a significant proportion of chemical fertilisers. Emerging technologies, such as precision farming, also offer farmers the opportunity to reduce fertiliser use by applying it only where it is needed most. Drones and satellite imagery can provide valuable information on soil conditions and nutrient deficiencies, allowing for targeted application of fertilisers.

Regen Ag Explained infographic- RegenZ


Practical strategies for farmers to reduce the harmful effects of chemical fertilisers on soil 

Transitioning away from synthetic fertilisers towards regenerative farming practices requires strategic planning and implementation. Over a period of three to five years, farmers can adopt several practical strategies to reduce chemical fertiliser inputs and improve soil health. These strategies include incorporating perennial pasture and crops, implementing cover cropping, practicing adaptive grazing, and utilising alternative amendments such as animal manure and compost. By following these methods, farmers can build soil carbon, enhance soil health, reduce input costs, and promote sustainable agriculture.

Utilise biological nitrogen fixation

Instead of relying solely on commercial nitrogen fertilizers, farmers can tap into biological nitrogen fixation, which is done primarily by bacteria associated with legume plants. By establishing or maintaining legumes in pastures and providing a suitable habitat for nitrogen-fixing bacteria, farmers can ensure a long-term and cost-effective supply of nitrogen for their crops and pastures.

Enhance soil carbon

Soil carbon is crucial for fostering soil health and plant fertility. Farmers can adopt the following principles to enhance the liquid carbon pathway and promote soil carbon buildup:

  • Provide year-round living cover through perennial pasture or annual cover crops to maintain actively growing roots in the soil.
  • Reduce nitrogen and phosphorus fertilisers that disrupt the carbon flow from microbes to plants, gradually decreasing their usage over time.
  • Promote plant and microbe diversity by incorporating various plant types and mixtures of grasses and broadleaves for cover crops and perennial pastures.
  • Utilize high stock-density animal impact to stimulate grazing’s positive effects on plant roots, nutrient cycling, water retention, and humus production. Grazing taller grasses maximises carbon sequestration and aids in building healthy soil.

Implement adaptive grazing

Well-planned and managed pasture-based operations can enhance animal and plant health, build soil health, support nutrient cycling, reduce costs, and provide economic returns. Adaptive grazing, which involves careful attention to pasture rest, recovery, and grass stubble height after grazing, can help maintain these beneficial qualities. Graziers should be flexible in moving livestock based on goals and the amount of grass stubble left behind, as stubble height directly correlates with pasture health.

Utilise alternative amendments

The sustainability of a farm system depends on more than just fertiliser use. Factors such as slope, texture, rainfall, and soil management practices have a greater influence on sustainability. Alternative amendments should be seen as minor components within a well-developed soil management system, fine-tuning it when necessary. These products are most effective when used alongside other sustainable practices such as forage-based rotations, cover cropping, and minimizing tillage.

Use animal manure

Animal manure can be a valuable resource when used in combination with other sustainable practices such as crop rotation, cover cropping, and green manuring. It adds important plant nutrients like nitrogen, potassium, and phosphorus to the soil while improving its quality. Proper timing of manure application is crucial to maximise its benefits for plants and soil, making it an effective means of enhancing soil and crop quality.

Employ compost

Incorporating compost properly is a long-term method for building soil fertility in organic production systems. Compost increases organic matter, enhances water holding capacity, improves soil structure and stability, suppresses soil-borne diseases, and enhances the presence of beneficial microorganisms. Over time, compost also improves nutrient availability in the soil, contributing to overall soil fertility.

Choose biological foliar fertilisers and soil conditioners 

Reducing chemical inputs doesn’t mean using zero inputs. Our sister company, Zylem, supplies  biological soil conditioners and foliar feeds that support sustainable agriculture and promote soil health and plant growth.

You may also be interested in: Is synthetic intervention part of regenerative agriculture?

Ready to reduce those inputs? 

Reducing chemical fertiliser inputs on farms is not only possible but also essential for sustainable agriculture. By implementing climate-friendly practices, farmers can increase yields, protect ecosystems, buffer against economic shocks, and contribute to global food security. The shift towards sustainable farming methods requires a holistic approach that incorporates regenerative farming techniques. With these strategies, we can reduce our dependency on chemical fertilisers and cultivate a more resilient and environmentally friendly agricultural system, and farmers can increase self-reliance, promote sustainability, and meet the growing consumer demand for nutritious, affordable foods.



justin platt photo- RegenZ

About the Author: Justin Platt

Justin is the Founder & CEO of Zylem and RegenZ. Justin has a BSc in Plant Pathology and Botany from UKZN. He has been involved in the agricultural services industry since graduating in 1979. Justin has a passion for regenerative agriculture.