July 2025

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 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.” 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: 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 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

When it comes to growing healthy, productive crops, your plants often reveal what they need — you just have to know where to look. According to soil scientist Dr Gordon Rajendram, leaves are one of the best indicators of nutrient deficiencies. Subtle changes in colour, shape, or spotting can highlight underlying issues before they affect your yield. Yellowing between the veins may indicate a magnesium deficiency, while stunted or distorted leaves often point to problems with boron or calcium. Left untreated, these issues can progress quickly. The good news? Foliar feeding offers a fast, effective solution. Unlike traditional root-based fertilisers, foliar sprays deliver nutrients directly to the plant’s leaves. This allows for quicker uptake and immediate correction of deficiencies, particularly during peak growth periods or when soil conditions are poor. It’s a practical way to support plant health and boost performance — without waiting for the soil to catch up. But foliar nutrition is just one part of a wider conversation: what should you really be putting on your land? Too often, fertiliser decisions are made based on habit rather than evidence. While it’s tempting to stick with what’s worked in the past, every season brings new challenges. Weather patterns shift, nutrient levels change, and crop demands evolve. Applying nutrients without soil data risks overuse, waste, and environmental harm. A smarter approach involves testing your soil regularly, understanding what your crops need at each growth stage, and tailoring your inputs accordingly. That might include slow-release fertilisers, biological amendments, or timely foliar applications. Finally, it’s important to move beyond the mindset of soil testing as a “spring-only” task. Nutrient availability isn’t static — it fluctuates year-round with rainfall, plant uptake, and microbial activity. Monitoring your soil throughout the year provides valuable insights and helps prevent problems before they start. As Dr Gordon Rajendram advises, tuning into what your plants and soil are telling you — and responding with targeted, informed action — is the key to growing stronger crops, protecting your land, and improving your bottom line. Contact Dr Gordon Rajendram 021 466 077 | rajendram@xtra.co.nz www.gordonrajendramsoilscientist.co.nz Contact MediaPA 027 458 7724 phillip@mediapa.co.nz