New research reveals grain analysis indicates success of nutrient management strategy

ADAS discusses new YEN nutrition service in Virtual Innovation Hub
The value of using grain analysis to diagnose phosphate deficiencies has been recognised for the first time. New recommendations for cereal crops and phosphate (P), outlined in the AHDB’s recently revised Nutrient Management Guide (RB209), are based on the culmination of ten years of research.

To help farmers benefit from this work, ADAS is launching ‘YEN Nutrition’, starting with a ‘Share-to-Learn’ Grain Nutrient Benchmarking service, which it will be discussing in the Virtual Innovation Hub.
The ‘principles of nutrient management and fertiliser use’ section of the Nutrient Management Guide has been revised with the benefit of a new understanding of soil health and the bioavailability of nutrients and includes updated information on crop analysis, soil sampling and phosphate management.
A new recommendation is that harvested materials from all crops (grain or non-grain) should be analysed routinely for P and other nutrients, to augment conventional routine soil testing. This will help to diagnose adequacy of P supplies as well as building intelligence about adequacy of other nutrients, and it will improve on-farm estimates of nutrient removals by any crop.
For good nutrient management, the total supply of nutrients from all these sources must meet, but not exceed, crop demand.
Crops obtain nutrients from several sources:

• Mineralisation of soil organic matter (all nutrients)
• Deposition from the atmosphere (mainly nitrogen and sulphur)
• Weathering of soil minerals (especially potash)
• Biological nitrogen fixation (legumes)
• Application of organic materials (all nutrients)
• Application of manufactured fertilisers (all nutrients)

Nutrients are applied as organic materials or fertilisers if the supply from other sources is unlikely to meet crop demand.
However, estimating crop demand and inherent soil supply is complex as these vary with species (and sometimes variety of the crop), yield potential, soil properties, weather (especially rainfall) and intended use (e.g. human food or livestock feed).
There are several tools for supporting this decision-making, but as Prof Roger Sylvester-Bradley, Head of Crop Performance at ADAS, comments: “Soil analysis tells us about soil availability and leaf analysis tells us about the immediate crop status – that is, the balance between uptake and use.
“It is important to register the different purposes that soil, leaf and grain analyses play, and that they are best used together, not as alternatives.
“Grain analysis adds particular value as it tells us about final crop performance. The grain stores most of the crop’s uptake of P, Nitrogen (N), Sulphur (S), Magnesium (Mg), Zinc (Zn) and Copper (Cu). Grain analysis summarises the combined effects of soil availability, fertilisers used and their efficiencies, crop rooting and topsoil moisture.
“We now advocate analysis of grain samples at harvest to gain an indication of the success of the overall nutrient management strategy. To support seasonal benchmarking of nutrient status, we will be sharing yields and additional crop and soil information.”
ADAS has used grain analysis for 2019 and the previous three harvests, and these have provided interesting insights.
Prof Sylvester-Bradley explains: “Although the 2019 data showed similar findings to the previous seasons – about 25% of the samples were deficient in N and about 50% deficient in P – the analysis also revealed that potassium (K) and Mg deficiencies were much more common in 2019 than in previous seasons. This may have been due to the dry April or the wet June in 2019, but the majority of samples were noticeably low in one or the other or both!
“We are looking to investigate this further at harvest 2020 with farmers engaged in YEN Nutrition; this will provide them with analysis and benchmarking of grain nutrient levels from six or more identified fields.”
The Nutrient Management Guide also revealed changes concerning phosphorus management, described by AHDB as “the first significant revision on phosphorus management for nearly 40 years”.
Phosphorous is important for energy transfer within a plant so is fundamental to life, however it comes from just two main sources: as natural P from manure, or manufactured P from crushed rocks from only a few sources in the world.
Prof Sylvester-Bradley continues: “Grain analysis is useful to find out about nutrient off-takes and this is especially useful in helping to guide P and K fertiliser decisions. However, critical thresholds are not available for all nutrients or are not yet reliable, so seasonal benchmarking enables each grower to see their own results set against all other crops in each season, and see whether their crops had high, average or low levels of each nutrient.
“Whilst we are introducing YEN Nutrition with just seasonal benchmarking this year, we are planning to add interactive benchmarking for next year; this will enable each advisor or farmer to compare their own results with any other subset of results – e.g. crop, variety, soil type, soil index, region, etc. – for any nutrient. In other words, anyone can start doing their own site-specific research at the click of a mouse.”
 
YEN Nutrition aims to provide the industry with a network and trustworthy site-specific results. It is being launched now, starting with its Grain Nutrient Benchmarking service. More information and registration can be found via the YEN website: www.yen.adas.co.uk/projects/yen-nutrition
More information about The Nutrient Management Guide: https://ahdb.org.uk/knowledge-library/nutrient-management-guide-rb209-amendments