BBRO Advisory Bulletin No 15 - W/C 28th July 2014
Rust and mildew continue to be found, and it is important that all crops now receive a full rate broad spectrum fungicide. Crops which are due to be harvested from October onwards will benefit from a second spray in about four weeks.
As you’d expect, our own fungicide trials are well under way in East Anglia and Lincolnshire and we’ll soon be conducting the first varietal assessments for their resistance to disease as part of the BBRO/BSPB Recommended List programme.
pH - With cereal crops clearing fast, soil sampling ahead of next year’s crops is stepping up a gear. It is critical to have a good understanding of how pH varies across fields as sub-optimal pH leads to inefficient use of all organic and artificial fertilisers applied. This, combined with the risk of micro-nutrient deficiencies, can directly reduce crop yield and impact on quality. For example, at pH 6 on a mineral soil, the nitrogen utilisation is only around 90% efficient. Where pH is found to be deficient, apply a fast acting liming product such as LimeX.
Base fertiliser - Soil analysis for base fertiliser requirements is essential for optimum plant nutrition. Ensure phosphate and potash offtake is balanced by a maintenance application on index 2 soils. On most soils, check P and K is maintained at index 2 by soil sampling every 3 to 5 years. Lighter soils will often not be able to hold sufficient nutrient to reach an index of 2.
Where organic manure is to be applied, base fertiliser applications should be adjusted accordingly. When making applications, use low ground pressure tyres to minimise soil compaction.
Boron deficiency adversely affects sugar beet yields and boron should be included in the analysis. Apply boron if the analysis shows that the soil contains less than 0.8mg/litre (ppm). Deficiency is unlikely to occur if soil contains more than 1.0mg/litre.
The table below summarises the BBRO’s base fertiliser recommendations.
*Only if exchangeable Na <25mg/kg
**On K index 2 soils it is only necessary to apply 100kg Na2O/ha when the soil contains less than 25mg Na/kg. Fen peats, silts and clays usually contain sufficient sodium and no fertiliser sodium is recommended.
Beet Cyst Nematode (BCN)
Soil sampling is the most effective way to determine the presence of BCN which, in severe situations, can reduce yield by more than 60%. A soil sampling service to establish the level of infestation is available through your British Sugar Area Manager.
Depending on the extent and level of infestation found, use of tolerant or light tolerant material is recommended, and again your Area manager will be able to advise you if you are in such a situation. More information about BCN is also available in the BBRO Sugar Beet Reference Book which can be accessed via www.uksugarbeet.co.uk.
The continuing hot dry weather has seen some crops starting to flag and irrigation of sugar beet is already underway on some farms. For those with the capacity to irrigate, more information is available in the recent Summer issue of the British Sugar Beet Review.
ALWAYS APPROVED PRODUCTS, ALWAYS READ THE LABEL AND COMPLY WITH INSTRUCTIONS
Caution: this information is based on results of experiments and experience but cannot constitute a recommendation.