Farmers and agronomists could soon benefit from a new Adas initiative aimed at improving crop nutrition, by testing grain and benchmarking results.
Work carried out as part of the Yield Enhancement Network (YEN) is already showing the value of grain analysis when assessing crop nutrition.
Soil test limitations
Soil analysis tends to be carried out every four years or so, and is an indicator of nutrient availability.
However, Adas crop nutrition expert Roger Sylvester-Bradley points out that it is not fully reliable and needs to be double-checked with other testing.
Leaf testing can be a useful indicator of the nutritional status of crops, enabling farmers to take corrective action.
But like soil testing, it has limitations. It is problematic to interpret, as there are weather effects and levels can change as crops age.
A more reliable measure is grain testing, which indicates if a crop actually captured enough nutrients throughout its life, giving a full post-mortem of crop nutrition.
Dr Sylvester-Bradley says another benefit is that it is much easier to get a representative sample from a field than with soil sampling.
“You just need to sample each trailer, bulk up the samples and you get a pretty representative sample.”
Deficiencies are widespread
Testing of grain samples from 633 YEN crops at harvest 2016, 2017 and 2018 revealed only 27% had no nutrient deficiencies, when tested for the 12 essential nutrients.
The 12 nutrients tested were nitrogen, potassium, phosphorus, sodium, calcium, magnesium, manganese, zinc, copper, iron, boron and molybdenum.
Another 27% had one deficiency, 21% were deficient in two nutrients while 4% have five or more deficiencies.
To help farmers identify and tackle potential deficiencies, Adas is planning to launch a new Crop Nutrition Network before harvest.
Farmers taking part will be able to learn more about the YEN findings.
However, the key component will be the gain sampling this harvest, which will be tested for the 12 nutrients and then benchmarked to see if they are similar to local crops.
Where there is a suspected deficiency, farmers will also be encouraged to carry out patch testing trials.
For example, where there is a low phosphate result (below the critical value of 0.3%), farmers will be encouraged to patch test applying phosphate fertiliser, thereby confirming the deficiency through a crop response.
Why take a farm-centric approach to crop nutrition research?
Previous work carried out by Adas investigating crop responses to nitrogen fertiliser found big differences between farms.
The project involved 18 farmers over four seasons, where they carried out tramline trials, applying 60kg/ha more and 60kg/ha less than the farm standard. The aim was to see if they were over- or underapplying nitrogen fertiliser.
However, the data revealed that 22% of the yield difference was down to the farmer. “Therefore, farmers themselves hold many of the secrets to improving productivity.”
Adas researcher Roger Sylvester-Bradley says that while small, replicated plot work is valuable for science, it does not address the problem of yield variation.
That’s why he believes a farmer-centric approach is the way ahead for crop nutrition research, to discover why some farms consistently outyield others.
For more information, see the Adas YEN nutrition webpage go to www.yen.adas.co.uk/projects/yen-nutrition
Roger Sylvester-Bradley was speaking at the recent Association of Independent Crop Consultants annual conference held near Towcester.