Study will attempt to solve nitrogen mystery

Feb 19 2008 by Sam Wood, The Journal

A NEW project aiming to establish best practice for estimating the amount of nitrogen available to the crop from the soil has been launched by the Home Grown Cereals Authority.

HGCA research director Graham Jellis said: “With fertiliser prices increasing and stricter regulations around the application of nitrogen, making the right fertiliser decisions is becoming more important. Estimating the amount of nitrogen available to the crop from the soil – the soil nitrogen supply – is crucial to the process. However, there is a lack of confidence across the industry of how soil nitrogen supply should be estimated.”

The project will aim to establish best practice for estimating soil nitrogen supply (SNS) by looking at when, where and how to use soil measurement timing, sampling, depth, sample handling and laboratory analysis of minerisable nitrogen. The project will also determine how best to account for over-winter crop nitrogen in oilseed rape.

The three-year project will make use of data from 25 years of soil nitrogen testing as well as establishing new trials.

Daniel Kindred, of Adas, lead scientist for the project, said: “We will be creating a new data set from around 50 sites per year for three years, measuring soil nitrogen in autumn and spring, as well as measures of mineralisable nitrogen.

“At these sites, the crop will be taken through to harvest without adding fertiliser, and the total N in the crop measured at harvest to give the ultimate measure of SNS for making comparisons.”