New guide lays it down on fertiliser use
The new AHDB Nutrient Management Guide (RB209) offers best practice guidance on the application of mineral fertilisers, manures and slurries to crops and grassland.
Last updated in 2010, its revision was overseen by the AHDB-led UK Partnership for Crop Nutrient Management and delivered by an ADAS-led consortium of experts from across the UK research community.
Of most interest to dairy farmers will be the sections covering principles of nutrient management and fertiliser use, organic materials, and grass and forage crops.
Key changes for farmers growing grass and forage crops
• Nutrient recommendations for grass and forage crops include guidance on how to use the field assessment method to calculate soil nitrogen supply.
• Grassland nitrogen recommendations have been revised to focus on target yield of grass production without linking to particular animal production systems (dairy, beef or sheep), milk yield, stocking rate or concentrate use.
• Whole season nitrogen requirements and nitrogen application sequences are provided separately for cutting and grazing situations. The total nitrogen recommendations can be adjusted according to soil nitrogen supply, grass growth class, and seasonal rainfall. The recommendations for nitrogen use in autumn grass establishment has been increased.
• There have been no changes to phosphate and potash recommendations for grazing, silage or hay systems. Minimum changes have been made to nutrient recommendations for maize and wholecrop silages.
• The nutrient recommendations for swedes, turnips, rape and kale have been altered to reflect more grazing in-situ, so fewer nutrients are being removed off the field. The nutrient recommendations for fodder beet have been increased due to higher yields being targeted.
Key changes for farmers using organic materials
• Nutrient content figures have been added for goat farmyard manure and farm-sourced and food-based anaerobic digestate. Digested liquid biosolids have been removed.
• Nutrient content figures have been updated for horse, cattle, sheep and duck farmyard manure, cattle and pig slurry, biosolids and compost. Nutrient content of poultry manure is presented according to dry matter content.
For farmers and growers producing and using organic materials, the updated figures in the organic materials section will be very useful when calculating their nutrient and financial values. The changes mean that calculations for organic materials are becoming more accurate.
The guide can also be downloaded as an iBook from the AHDB website, www.ahdb.org.uk/RB209. Also available as an app, the guide can be found by searching for RB209: Nutrient Management on the App Store.
Thom Washbourne is AHDB Dairy knowledge exchange officer, West Midlands