Tillage farmers have been advised to carry out grain sampling at harvest by the Potash Development Association (PDA).
It has highlighted that the subsequent analysis result could prove helpful for farmers monitoring the success or limitations, regarding input decisions taken and soil management practices implemented during the previous growing season.
It is generally acknowledged that it is always difficult in agriculture, particularly in an annual cropping cycle, to successfully achieve this.
This can be due to the time span involved and the number of variables that are at play during the process.
However, there is a strong bank of evidence to confirm that grain sampling and analysis at harvest can influence decisions for the coming season in a very beneficial way.
This can be pinpointed in crops grown on low phosphate (P) index soils, or those that have not been able to access sufficient phosphate during the growing season, which are likely to show low levels in the grain.
However this may not be quite so clear cut for potassium (K) as the results of experiments have shown relatively stable levels of grain potassium, despite big variations in yield and soil K levels.
Although for K this may mean it is difficult to use these results to influence decision making for future management, it does mean that growers can more easily budget K removals and therefore replacement levels.
Grain sampling
Grain sampling may be also be harder to achieve with other nutrients where final yield and crop quality vary in response to differences in soil supply.
Recent work carried out by the Agriculture and Horticulture Development Board (AHDB) has indicated that sampling at harvest is a more accurate measure of true offtakes based on site and season specifics.
Analysis of the grain after harvest can help to indicate whether nutritional input decisions during the season were appropriate.
Data complied by NRM’s laboratories reflects the grain analysis trends identified for harvest 2022, relative to 2021.
The figures show that there was a 4% lower N off take, 8% lower off take for P, and a 3% lower grain off take for magnesium Mg last year, compared to the year previous. However, there was a 4% higher off take for K.
According to agronomist, Tom Land, there is a value of tissue testing crops in order to identify their exact nutritional requirements throughout the growing season.
Growers he said can get a clear and real-time picture of what is happening in a crop at any given point.
The tissue testing process can identify what nutrients are being taken up by a crop, allowing growers to make alterations to nutritional programmes to rectify any deficiencies.