Tillage Edge Update 25th February 2021
Mark Plunkett, Soil & Plant Nutrition Specialist reports from a number of tillage fields in the southeast on how crops have developed over the recent months. Crops have over wintered will with well rooted and good tiller development. Crops look to have greened up well despite the cold, wet weather
Crops look to have greened up well despite the cold and wet weather over the last number of weeks. Nitrogen is not a limiting factor for the majority of crops at present as demand is low due to soil and weather conditions.
In the Fields Crop Update
Winter Oilseed Rape
Later sown crops of winter oilseed rape have been heavily grazed by pigeons over the last number of weeks and have lost a lot of leaf during that period. These crops will require an application of N once soil and weather conditions improve. Before applying fertiliser N check the following (met.ie) to ensure applied N will be used efficiently by the crop and reduce loss risk to the environment:-
- Soil temperatures >5.5 ᵒC & rising
- Good soil trafficability
- An improving weather forecast
A compound fertiliser maybe applied to supply crop P & K requirements as well as early crop N to increase crop green leaf area index (GAI) and deliver target GAI of 3.5. Where possible select an ammonium forming fertiliser (protected Urea) for the 1st split. This will be a safer form of N and will reduce N losses to both air and water. Check the farm fertiliser plan for P & K advice and see table 1 below showing fertiliser N, P & K recommendations for a 5t/ha yielding crop for winter oilseed rape.
Winter Barley & Wheat
Both winter wheat and winter barley crops have over wintered well with good tillering and rooting visible. Crops have good colour despite the very cold and wet weather encountered over the last 2 months. Examine crops for over wintered weeds such as cleavers, speedwells, mayweeds, groundsel etc... and consider most suitable options to tidy up weeds when conditions are suitable.
Figure 1:- Winter wheat in the tillering phase with 3 well developed tillers (GS 23).
Table 2 below shows the P and K requirements for a crop of winter wheat and barley yielding 10t/ha and suggested fertiliser types and rates 9to supply crop P & K’s). A well prepared farm fertiliser plan will provide a list of suitable fertilisers at this time of the year and will ensure that the correct fertiliser types are available for the crops on your farm. Aim to apply P & K’s over the coming weeks as soils and weather conditions improve.
Table 3 below shows P and K advice for a 9t/ha crop of winter oats. Oats have a large demand for K due to high K levels removed at harvest time in oaten straw. Additional K can be supplied as muriate of potash (50%K) which can be applied at any time of the year to replenish and maintain soil K levels.
Where organic manures have been applied the figures in tables 1, 2 and 3 will need to be adjusted, for example a 1,000 gallons of cattle or pig slurry is equal to a 50kg bag of 6-5-32 or 19-7-20, respectively.
To prepare a fertiliser plan a number of pieces of information will be required as follows: - up to date soil test results, cropping plan, field areas and previous crop yields (last 3 years). Teagasc have developed a new online fertiliser planning tool (NMP Online) which will produce a farm fertiliser plan on a crop by crop basis and soil fertility maps for your farm. Contact your local advisor / consultant to prepare a fertiliser plan for 2021.
For more information on Teagasc Tillage check out https://www.teagasc.ie/tillagemonth/