Nutrient Rich Strips are not new in cropping. They are used to see if there is a clear growth response to an applied nutrient. But it is often hard to quantify the response and translate it into fertiliser rate recommendations. Some fertiliser advisors are using a new tool to address this issue.
Nitrogen is the most common nutrient rich test strip used, because N can be topped up within the season. The N rich strips act as ‘Nitrogen Fuel Gauges’. The strips are laid down immediately after sowing.
The nitrogen rate in an N rich strip might be double or triple the starter N rate. In WA the typical rate in the N rich strip is about 60 kg of N per hectare. Advisors often use liquid fertiliser products to apply the N from a quad bike boomspray.
Western Australian company Summit Fertilisers uses GreenSeeker® technology to assess in-paddock N test strips. They interpret the results through their N calculator to give growers same-day results and fertiliser recommendations.
Advisors use the GreenSeeker® to take readings both on and off the test strip. These are done between 20 and 70 days after planting, before any in-season application of N.
The GreenSeeker® measures Normalised Difference Vegetation Index (NDVI). This is a graphical indicator that quantifies green vegetation. It shows the biomass responses to applied nutrients. The difference in crop growth indicates if applying more fertiliser will improve yield and profitability.
Advisors then suggest a rate of N to apply. They aim to maximise yield potential, or hit a protein target, in a profitable way.
Evaluating the potential response and making a same-day recommendation should increase growers confidence in their decisions to top up N through the season.