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Tillage Update 17th March 2022

In this week's Tillage Update Mark Plunkett, Teagasc Crops Soil & Plant Nutrition Specialist, has advice on the first fertiliser application to winter cereals, slurry application and trace elements. Mark also advises maintaining a soil pH of 6.5 for spring cereal crop production.

Winter crop growth on the increase

Springtime is here with longer and brighter days with improvements in plant growth.  As we move into this time of the year the favourable conditions for growth increases the plants demand for major plant nutrients such as N, P, K & S.  Over the last number of weeks, there has been quite significant amounts of rainfall.  With improving soil and weather conditions, aim to apply fertiliser to winter crops as these crop will be requiring their first application of major plant nutrients if not already applied.

First fertiliser application to winter cereals

Winter Barley - Once field conditions improve apply first split of nitrogen plus crop P and K requirements. Aim to apply ~ 25 to 30% of the crops N requirements, in many situations the fertiliser blend selected will supply sufficient N and it’s N form will be ammonium based N which is a safer form of N at this time of year.     

Winter wheat – Aim to apply ~ 25% of the crops N requirements by mid-late March or GS 30.  Complete P and K applications in the 1st split. Where plant populations are not on target or where take-all is a risk increase the rate to 75kg N/ha in the 1st split.

Slurry application to winter cereals

Due to high fertiliser prices and issues with supply, applying cattle / pig slurry to growing crops of winter barley / wheat is currently practised. This is a very efficient way of utilising the N, P & K in these manures plus the addition of organic matter / carbon.  Aim to apply 22 to 33 m³/ha (2 to 3,000gals/ac) with an umbilical system.  For example a 10t/ha winter barley crop receiving an application of 28M³/ha (2,500 gals/ac) of pig slurry will supply ~ 58kg N, 22 kg P & 56kg K/ha.  This application will supply sufficient N for the 1st split and ~55% of the crops P & K requirements.

Trace elements 

Check soil test results for minor nutrients such as manganese, copper & zinc.  Where soils are very low to low (Index 1 or 2) apply foliar trace elements now at mid-tillering and complete stem extension (GS 30/31).  Aim to apply 15kg S/ha for both winter and spring crops.

Spring crops

As soil conditions improve, planting of spring crops will be kicking off around the country.  With the increasing costs of fertilisers, it is more important than ever to make sure soil pH 6.5 is maintained for spring cereal crop production.  Check soil test results and where lime is required apply in advance of sowing and work well into the seed.  For sensitive crops such as spring beans or fodder beet a higher soil pH 6.8 to 7.1 is required. 

With the rising costs and tight supplies of fertilisers aim to apply sufficient N, P and K based on average grain yield over the last 3 years.  Where possible combine drill especially P low index soils (Index 1 or 2) as it brings many benefits especially in the first 3 to 6 weeks in supporting rapid root and plant development for the spring barley plant.  Aim to apply all P and K at sowing time and apply ~ 25 to 30% of the crops N requirements at sowing time.

Find out more information and advice from the Teagasc Crops team here.   The Teagasc Crops Specialists issue an article on a topic of interest to tillage farmers every Thursday on Teagasc Daily.  Find your local Teagasc office here