Together with the New Zealand Asparagus Council, we were fortunate to obtain funding from “Our Land and Water” to investigate nitrate best practice management.

We surveyed a number of growers about fertiliser and nitrate management practices. We find growers generally have good management for transport, handling and storage. We see a wide range of practices for nitrate management including rates and timing, and this is what we are trying to understand.

We have established five trials, two in Hawke’s Bay and one each in Mangaweka, Manawatu and Mid-Canterbury. We are monitoring nitrate levels in soil, roots and fern, to build a picture of how the amounts move between these pools.

As part of the project we offered fertiliser application equipment calibration, and the machines tested were doing an acceptable job. We used the fertspread tool to complete calculations and produce reports.

While a large number of samples have been sent to the Eurofins lab for analysis, we are also using the Nitrate Quick Test to assess nitrate in the soil at three depths in each plot.  When we compare the results of the quick test with lab results, we find a good agreement. The key is making sure the soil sampling is done correctly so it is representative. 

Many thanks to the growers hosting and supporting the trials, and the NZAC and Our Land and Water for support and funding.