Overview
The three trials covered in the aforementioned paper were conducted at Cloverdale Holdings a 730 Ha, 2900 cow dairy farm near Ashburton from December 2009
This summary outlines the findings of a four-year New Zealand dairy farm study investigating how humic compounds improve the efficiency of nitrogen fertiliser, particularly when applied as a liquid (foliar) application.
The trials compared traditional granular urea with dissolved urea applied by foliar spray, both with and without added humic acid. Across three replicated trials, results consistently showed that adding humic compounds significantly increased pasture dry matter production and nitrogen use efficiency.
Key findings from the study include:
- Up to three times more pasture grown per unit of nitrogen when urea was applied as a liquid with humic acid, compared to granular urea.
- Average dry matter increases of 9–18% when humic acid was added, with one trial achieving an additional 2,681 kg DM/ha.
- The research demonstrated that farmers could reduce nitrogen inputs by up to 65% while maintaining or increasing pasture production.
- Foliar application resulted in higher plant uptake of nitrogen, reduced losses to leaching and runoff, and improved environmental outcomes.
- Additional benefits observed included deeper and denser root systems, lower nitrate levels in pasture, and positive animal health indicators.
The study concludes that combining dissolved urea with humic compounds delivers a highly efficient fertiliser system, producing more pasture with less nitrogen input and lower environmental impact.
👉 Download the full summary PDF below to explore the trial data, charts, and detailed results.