Impact of different Nitrogen fertiliser application methods on grass yield and nitrogen use efficiency within a UK dairy grazed trial area

Description

Changes in food consumption habits and world population have driven the requirement for higher Nitrogen (N) rates to obtain higher crop yields. Recent increases in fertiliser cost have generated changes in N fertiliser use, with producers seeking more efficient and cost-effective application methods. One important development is foliar N application onto grass. Literature shows that foliar N has a greater Nitrogen Use Efficiency (NUE) than granular N, allowing for reduced application rates. However existing literature is based either on pot experiments; outside the UK or not inclusive of frequent biomass removal, such as grazing.

This project was designed to assess foliar N performance compared to granular N on grazed grassland. Farming Connect’s ‘Foliar Feed for Grassland’ project ran from 2019 to 2021, aiming to enhance previous relevant literature. Three trial areas receiving different N fertiliser regimes were set up: conventional (granular), foliar and control (no N application) and were commercially grazed by dairy cattle. Dry Matter (DM) growth was measured weekly between March and October, fortnightly in February and November, and monthly in December and January using a sward plate meter, calculating yield per hectare (kgDM/ha). The clover in the sward was considered in the results and its impact on the production of the sward. The trial showed conclusively that the NUE of foliar N was 570% greater than that of conventional N application, allowing reduced N usage to obtain a similar yield. The average foliar application DM yield was 0.8% (0.1tDM/ha) greater than the conventional yield, despite the N application rate averaging 166kgN/ha less. Clover populations recovered from suppression by granular N application, from 5% cover up to 20% in the foliar and control areas. There was a 71% decrease in financial costs through foliar N, whilst achieving competitive yields. Additionally, reductions in N use will consequentially reduce agriculture’s greenhouse gas (GHG) emissions whilst upholding and potentially increasing yields.

Period	7 Dec 2023
Event title	Hartpury University Research & Knowledge Exchange Conference 2023
Event type	Conference
Organiser	Hartpury University
Location	Gloucester, United KingdomShow on map