Ground Breaking New Zealand Field Trials By Leading Hamilton Soil Scientist Dr Gordon Rajendram Indicate That Foliar Fertiliser Boosts Spring Pasture Growth In Canterbury Region
One of New Zealand’s leading soil scientists, Dr Gordon Rajendram, says foliar fertilisers hold the key to farmers overcoming Canterbury’s cool late winter/early spring major challenges for pasture growth.
Dr Rajendram, who is based in Hamilton, says results from his research field trials have revealed foliar fertiliser provides the necessary boost to pasture growth especially when soil temperatures are low and nitrogen uptake through the roots slow to a crawl.
Foliar fertilisation involves spraying water-soluble nutrients directly onto plant leaves. It’s like a targeted nutritional top-up, allowing plants to absorb nutrients almost immediately through their foliage via stomata, cuticle and leaf hairs.
“This method is proving effective in cold climates like the Canterbury region incurs,” says Dr Rajendram.
“Foliar sprays deliver nutrients exactly when and where they’re needed,” he says. “You’re feeding the plant directly, so it bypasses the limitations of cold soil conditions and kickstarts growth quickly.”
AgResearch Backs the Science
Dr Rajendram isn’t the only one seeing these results. AgResearch, one of New Zealand’s leading agricultural science organisations, has conducted similar trials with consistent outcomes. In fact, foliar fertiliser has demonstrated efficiency rates of up to four times higher than granular applications.
Faster Response, Less Fertiliser
Graph 1
One replicated pasture trial in New Zealand revealed that just 9 kg N/ha as foliar urea achieved the same grass yield (1,426 kg DM/ha) as 37 kg N/ha of granular urea. The response is rapid for a 24 day period. That’s a powerful statistic – it means foliar N delivered about 61 kg of dry matter per kg of N, compared to just 14 kg/kg N for granular urea. “With a quicker plant response and fewer applications needed, this method saves time and product, offering real cost-efficiency to Canterbury farmers,” Dr Raendram’s trials have uncovered.
Dr Rajendram notes: “Granular urea is only about 35% efficient, while foliar applications are faster and use less product overall. That’s a win for farmers and the environment.”
Table 1
Unit N40 (extra kg DM per unit N applied over 40 days of growth) for the different seasons and regions using Granular Urea.
Reference: G.S Rajendram et al (2009). Nitrogen Fertiliser Trial Base. Taken from 1272 Nitrogen Fertiliser Response trials throughout New Zealand over 80 years conducted by MAF and AgResearch.
Environmental Benefits
With Canterbury’s sensitivity to nitrate leaching and water quality issues, foliar fertilisers offer an environmentally responsible choice. Because nutrients are absorbed directly by leaves rather than moving through the soil, volatilisation and there is less chance of leaching into waterways. The reduced volume of fertiliser required, further supports sustainable practices.
Practical Advice for Canterbury Farmers
Dr Rajendram advises farmers to use foliar sprays as a complement to their existing soil fertilisation strategies. For best results, he recommends applying in the early morning or when there is dew on the leaves – and avoiding hot, dry days to prevent leaf burn.
Summary
If you're farming in Canterbury and struggling with sluggish pasture growth during late winter/early spring, foliar fertiliser may be the answer. Backed by an AgResearch study and Dr Gordon Rajendram’s decades of expertise, this method offers:
- A faster response during cold weather
- Less product required
- Up to 4× greater efficiency than granular fertilisers
- Reduced risk of volatisation and nitrate leaching
By integrating foliar feeding into your nutrient management plan, you can keep your pastures thriving and your inputs low – even during the chillier months.
References
- Rajendram, G. S. (2025). Grow more grass in the colder months. Gordon Rajendram the soil scientist.
- Rajendram, G. S., et. al. (2009). Nitrogen fertiliser response trials over 80 years in New Zealand. New Zealand Journal of Agricultural Research, 52(4), 511–528.
- Chalker-Scott, L. (2015). Foliar fertilisation in plants: A review. Journal of Plant Nutrition, 38(3), 376–390.
- Mosali, J., et al. (2020). Foliar phosphorus application improves wheat P-use efficiency. Field Crops Research, 250, 107792.
Contact Dr Gordon Rajendram
021 466 077 | rajendram@xtra.co.nz
www.gordonrajendramsoilscientist.co.nz
Contact Phillip Quay
MediaPA
027 458 7724
phillip@mediapa.co.nz