GrowHow acts on HGCA Soil Nitrogen Supply Prediction research results
GrowHow UK has welcomed the findings from the HGCA-backed independent research into Soil Nitrogen Supply (SNS) predictors which were previewed today (5 December), at the 2011 HGCA Agronomists' Conference held in Daventry. The full report, which is to be published in the New Year has taken four years to produce. It confirms the value of the GrowHow Additionally Available Nitrogen (AAN) measurement in predicting the amount of nitrogen that will come from the soil. The AAN test is part of the company's unique N-Min Service.
Commenting on the findings, GrowHow Arable Agronomist Allison Grundy said: "Independent validation of our N-Min Service is welcome news and I think it is fair to say that some in the steering group were surprised at how well it performed."
One of the key conclusions from the Establishing Best Practice for Predicting Soil Nitrogen Supply project (HGCA Project 3425) is that a Soil Mineral Nitrogen (SMN) test on its own is a relatively poor indicator of the amount of nitrogen that will come from the soil. However, including the GrowHow AAN component as well as the SMN (as measured in N-Min), greatly improves the accuracy of the prediction.
"But this research has done more than just compare the predictors. Its real value for N-Min is that it has enabled us to learn how to improve the accuracy of the service and, at the same time, target it more precisely to the fields where it will bring the best return for farmers, helping achieve best value from their soils and fertiliser inputs," says Allison Grundy.
The GrowHow N-Min Service has therefore been enhanced and simplified for the 2012 season.
"Previously, we used a proven calibration model to estimate the Nitrogen in the 30-60cm profile. In the light of this research we have decided to ask for samples to be taken down to 60 cm depth, or for shallow soils, a sample to the maximum rooting depth, to further improve the accuracy of the N-Min."
The very best predictor, according to the SNS project, was an N-Min to a depth of 90 cm. However sampling to 60 cm is a far more user friendly and practical solution and, according to the research, almost as accurate, so this has been selected as the sampling depth for the standard N-Min service.
Allison continues: "We are also introducing a new N-Min 90 service which will cater for samples taken down to 90 cm. This extra option gives farmers and their advisers the opportunity to sample to depth and it will be particularly useful for farms with high organic matter, peaty and deep silty soils as well as those with high residues following vegetables and grass."
The Establishing Best Practice for Predicting Soil Nitrogen Supply SNS project was set up in November 2007. It has been funded by HGCA and co-ordinated by ADAS. Scientific partners were NIAB/TAG, Scottish Agricultural Colleges, Eurofins Laboratories, NRM Laboratories and Hill Court Farm Research. Input also came from Rothamsted Research, Horticultural Development Council, Processors & Growers Research Organisation, Clive Rahn Plant Nutrition and Ian Richards from Ecopt. GrowHow contributed by providing additional field sites and access to the company's research collected over the past 10 years to validate, enhance and progress the N-Min Service. The full report is expected to be published early next year.