Monday, February 26, 2024

An invitation to analyse your arable crop

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Analysing the nutrient level of harvested crops can improve returns and yields.
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New Zealand arable growers keen to improve returns through nutrient analysis of harvested grain and seed crops are encouraged to participate in a pilot programme being run this harvest. The Foundation for Arable Research-initiated programme follows up a session with United Kingdom crop expert Professor Roger Sylvester-Bradley, who suggested NZ arable growers are missing out on vital crop management information, and potentially additional yield and returns, by not analysing the nutrient levels of their harvested crops.  

“I have been in crop nutritional research for more than 50 years and I cannot understand why we haven’t done this before,” Sylvester-Bradley told an online seminar with growers organised by FAR.

Most growers in the UK and NZ don’t carry out crop nutrient analysis. 

Analysis of protein and nitrogen has generally been a tool to indicate the marketability and value of a crop in terms of quality, but crop nutrient analysis is now being promoted as a way for growers to check post-harvest how well they are managing their biggest input, being nutrients.   

Sylvester-Bradley leads the Yield Enhancement Network (YEN) in the UK; it has found that more than 80% of crops on 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 in 2013 in the UK to get better data on crop yields and for benchmarking. 

In 2020, a YEN nutrition programme was started, analysing the nutritional status of growers’ crops to identify fertiliser over-use, show potential savings and diagnose deficiencies. 

While predominantly assessing the nutrient status of wheat and barley, other crops have included oats, oilseed rape, beans, linseed, triticale and rye.   

Sylvester-Bradley recommends that as well as conducting a normal soil analysis every three to five years, growers also do 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 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.”   

UK data shows that there is a lot of variation between what Sylvester-Bradley refers to as “stingy farms” and “generous farms” in terms of crop nutrient status.

“This shows that some farms are erring on being too cautious in providing good nutrition whereas other farms are too generous.”  

In the UK, critical levels have been determined for eight of the 12 essential nutrients, below which a crop is deficient to a degree that impacts on yield. 

UK data shows that more than 50% of crops are deficient in more than one nutrient and 20% of crops receive excess nitrogen. 

The biggest deficiency is of phosphorus, but nitrogen, magnesium and sulphur deficiencies are common. 

YEN nutrient data shows that 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.”  

NZ growers have the opportunity to learn more about the nutrient status of their grain and seed crops through FAR-initiated pilot programme this harvest.

To participate, growers need to supply harvest samples for analysis.  

FAR Growers Leading Change facilitator Donna Lill said the inaugural project is an opportunity to tap into the expertise of the UK’s YEN programme. 

The cost is about $150 for each paddock sample. This covers lab analysis and two YEN Nutrition reports. 

“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.” 

FAR plans to hold a meeting with participants later in autumn to discuss the results and what they might mean for paddock management. 

Growers are advised to plan now and have sample bags labelled and ready for harvest to collect a representative sample for each paddock, much like they will already be doing for merchants.  

Growers interested in supplying crop samples for analysis should contact Donna Lill at email:

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