The UK’s Yield Enhancement Network (YEN) head Prof Roger Sylvester-Bradley revealed this during a webinar with growers organised by the Foundation for Arable Research (FAR).
"I have been in crop nutritional research for more than 50 years and I cannot understand why we haven’t done this before."
Most growers in the UK and New Zealand don’t carry out crop nutrient analysis.
Analysing protein and nitrogen indicates the marketability and value of a crop in terms of quality. However, crop nutrient analysis is now being promoted as a way for growers to check how well they are managing their biggest input — nutrients — after the harvest.
Prof Sylvester-Bradley has found more than 80% of crops on UK farms show a deficiency in at least one nutrient.
"Nutrient concentrations at harvest show whether crops captured insufficient, adequate or excess of each nutrient. Without measures at harvest, nutrient management is guesswork and this prevents improvement."
YEN began to get better data on crop yields and for benchmarking in 2013. A nutrition programme was started in 2020, analysing the nutritional status of growers’ crops to identify fertiliser over-use, show potential savings and diagnose deficiencies.
While mainly testing the nutrient status of wheat and barley, other crops have included oats, oilseed rape, beans, linseed, triticale and rye.
Prof Sylvester-Bradley recommended growers carry out a normal soil analysis every three to five years and a grain analysis on all 12 essential nutrients every year.
"In my mind, the top priority is not the soil analysis, or leaf analysis, but grain analysis, as that represents the final result of all the decisions you have made in growing your crop. It is easy to do, costs a bit more than soil analysis, but is well worth it."
The nutrients are nitrogen, phosphorus, potassium, sulphur, magnesium, calcium, iron, manganese, zinc, copper, boron and molybdenum.
"While these are required in different amounts, they are all essential, so if we are good managers we need to be monitoring these."
UK data shows there is a lot of variation between "stingy farms" and "generous farms" in crop nutrient status.
Prof Sylvester-Bradley said this showed some farms were being too cautious in providing good nutrition whereas other farms were being too generous.
UK data shows more than 50% of crops are deficient in more than one nutrient and 20% of crops receive excess nitrogen. The biggest deficiency is phosphorus, but nitrogen, magnesium and sulphur deficiencies are common.
YEN nutrient data shows 25% of paddocks have deficiencies costing more than $610 a hectare. Differences in wheat protein can be as much as 4% below, or more than 2% above the optimum level.
"So, 25% of sampled crops were mismanaged as far as nitrogen is concerned and the financial implications are quite big."
Growers are advised to look for a trend and see whether a particular nutrient is being under- or oversupplied over all crops on their farm.
Prof Sylvester-Bradley said he would expect some differences in critical nutrient levels between New Zealand and the UK because of climate differences, and this was already evident between the UK and Denmark.
New Zealand growers interested in learning more about the nutrient status of their grain and seed crops are being encouraged to participate in a FAR-initiated pilot programme being held for the first time this harvest.
They will need to supply harvest samples for analysis at a cost of about $150 for each paddock sample to cover laboratory analysis and two YEN nutrition reports.
The FAR’s project co-ordinator, Donna Lill, said it was an opportunity to tap into the expertise of the YEN programme.
"The benefit of working with YEN UK is they have the systems and database. They also have the knowledge around benchmarking and the critical levels for different nutrients. There may be differences between the UK and New Zealand, but it is a starting point.’’
The FAR plans to hold a meeting with participating growers in autumn to review the results for future paddock management.
