Soil fertility is at the heart of good farming and is critical to the productivity and profitability of both grassland and tillage cropping. Irish farmers’ ability to produce some of the highest yields of grass in the world is due to our soils and our climate. The same is true for grain production that Irish farmers can exploit the high yield potential of modern varieties developed by plant breeders.
Soil sample results for soils analysed at Teagasc show that 90% of samples have sub optimal levels of the principle soil nutrients Lime, Phosphorus (P) and Potassium (K). Mark Plunkett, Teagasc Soil and Plant Nutrition Specialist said: “This is a serious limitation to the production potential of our soils and limits our ability to maximise our most competitive advantage in the market place which is our ability to grow high yields of quality grass and grain. High grain yields are essential for profitable cropping and good quality grass is a cost effective feed stuff for our livestock enterprises”.
According to Dr David Wall, leader of the Teagasc soil fertility research programme at Johnstown Castle; “The first principle in fertiliser planning is controlling soil acidity through liming soils on a regular basis. Soil test results indicated that 60 to 65% of our soils require lime on a regular basis to maintain a soil pH 6.3 for grassland and pH 6.5 for tillage cropping. Lime is a cost effective soil conditioner and in effect is a fertiliser as it is required to unlock major soil nutrients. For example our soils contain tonnes of soil organic matter and by maintaining soils close to the optimum soil pH up to 80kg of Nitrogen per hectare per year will be released. Phosphorus (P) is increasingly a more expensive nutrient due to its limited stocks worldwide. To maximise the availability of soil P and P applied in either manures or compound fertilisers, it remains critical to maintain soil pH 6.3 to 6.5 for grassland and tillage cropping respectively”.
Lime should only be applied on the basis of a recent soil test report and it recommends the rate of lime based on the soil pH and the soil type. Aim to put a liming programme in place and apply lime to fields with the lowest soil pH levels. It is good practice to target 20 to 25% of the farm on an annual basis.
September is the ideal month of the year to start planning lime and fertiliser applications to maximise the potential of the soils on your farm. For example now is a good time to consider lime applications for either grassland or tillage farms. Lime spread at this time of the year will have a good opportunity to work and adjust soil pH to the target over the winter time. In addition it will help identify fields that may benefit from extra P & K in the form of farm yard manure, cattle slurry or pig slurry to build soil P and K levels to the optimum level of Index 3.
September Discount on Soil Testing
For the month of September, Teagasc is offering its clients 6 soil samples for the price of 5 for early delivery to the soil testing laboratory. “This will ensure that up to date results are available to plan lime applications, make best use of valuable manures and ensure money is well spent,” said Dr Tom Kelly, Director of Knowledge Transfer at Teagasc. A soil sample is a small cost of €0.50c/ac/year and will provide specific farm information for the soils on your farm to maximise both grass and grain production annually.
