Gear up for Grain Sampling – Ben Burrows July 2021
Last harvest we encouraged our clients to take grain samples for nutrient analysis, a practice which is encouraged by the AHDB and YEN competition. In total we had over 100 samples to send to the lab and collect into a data set – this year it would be great to have even more!
Along with other, long established ways of monitoring crop nutrition such as soil testing and tissue testing – grain analysis is another useful method of reviewing how well (or not) plants have been able to get hold of essential nutrients. However, unlike tissue testing, which is useful as a ‘snapshot’ in a particular moment in time, grain analysis shows the accumulation of nutrients throughout the entire growing season. For example, you may take 2 or 3 tissue tests during the growing season, each of which shows that the plant is low in Boron. The grain analysis should help identify whether those apparent deficiencies actually translated through to inadequate Boron levels in the grain, or whether actually, the crop was in the end able to find enough Boron in the soil or from supplied foliar feed.
I thought it would be interesting to review a couple of the interesting trends we identified from our overall CMP dataset last year, starting with Sulphur…
We noticed that on the Group 1 milling varieties, the Nitrogen:Sulphur ratio appears to drop from the optimum of about 14:1. It is likely that these varieties are receiving higher rates of Nitrogen fertiliser, to help increase protein levels but perhaps Sulphur levels are not also being increased. The opposite is true of malting barley, for example Maris Otter has quite a high N:S ratio – less Nitrogen is being applied relative to the amount of Sulphur!
Next, onto Potassium. This is a nutrient which appears to come back as deficient on almost every tissue test taken during the spring – especially during periods of rapid plant growth. It would not have been a surprise to find that many of our grain samples would have low levels of K in the grain.
However, when looking at the grain analysis data, very few actually reported low Potassium levels. This is why it is important to consider soil, tissue and grain samples together – using all three can help build up a good picture of what nutrients your crop is consistently struggling to find enough of and you can then tweak your fertiliser plan or foliar feeding appropriately.
We will have sample bags and lab forms available from the office or via your CMP agronomist, as with last year ideally samples should come from particular fields off the combine or as trailers are coming into store – rather than sampling the whole heap after harvest. It is obviously an incredibly busy time – so worth planning where samples are likely to come from beforehand!