Soil Fertility Management On the Tillage Better Farms Programme in Ireland.

Introduction

Soil nutrient management is a key component in Irish tillage farming in order to maintain soil fertility and to realise crop yield potential and maximise farm profitability. This is one of the key components of the Teagasc, Tillage Crop BETTER Farms programme. This programme has being running since 2009 in conjunction with three farms in Ireland. The programme was established to provide a platform for technology transfer and for demonstrating best practice concerning many aspects of tillage farming in Ireland. On the three farms being monitored there is a history of soil sampling and targeted fertiliser applications to meet crop requirements. Over the past three years the fields on these farms have been intensively soil sampled to assess changes in soil nutrient status and to evaluate the fertiliser application programmes in relation to the soil type and crop rotation on each farm.

Materials and Methods

Three tillage farms (A, B & C) were selected to represent the main areas used for arable crop production in Ireland. These farms were intensively soil sampled in 2009 and re-sampled in 2011. Fields were divided into sampling area units and sampled to a depth of 10 cm, where 20 soil cores were mixed together as one composite sample.  Samples were taken after cereals crops were harvested and samples analysed for soil pH, Morgan’s -P, -K and -Mg. Each farm is supported by a local Teagasc tillage extension officer, tillage agronomy specialist and research staff in order to help implement and assess the impacts of proven technologies and best practices on the farm.

Results and Discussion

On Farm A farm the overall soil P levels have improved with fewer soils at the very low levels (Index 1). Soil K levels on the farm have been more variable with an increase in the very low (Index 1) soils and also an increase in very fertile soils (Index 4).  On Farm B (sandy loam) soil P and K levels have changed significantly. The percentages of soils at index 2 have increased from 12 to 53%, while soils at index 3 have decreased from 65 to 41% and none of the soils at index 4. Soil K levels show a similar trend in that the percentage of soils with very low and low K levels (index 1 and 2) have increased, while the percentage of soils at K index 3 decreased from 29 to 6% over this period. On Farm C soil test results show no change in soil P levels over this period.  Soil K levels show a positive change with the percentage of low K soils (index 1) decreasing from 44 to 22%, soils and the percentage of soils in K index 2 and 3 increasing by 12% and 11% respectively.

Conclusions

On Farm A the crop rotation now includes more winter cereals. The fertiliser strategy has changed to supply the correct P and K balance to better match both soil and crop P and K requirements. On Farm B continuous winter barley production on a sandy loam has shown that additional P and K is required to meet annual crop requirements and maintain soil fertility levels. On Farm C crop types are suited to the soil types and soil fertility levels. On this farm soil fertility levels have remained relatively stable despite any shortfalls in nutrient inputs in any one year, as adequate nutrients are being supplied when appropriate on a longer term basis.

Acknowledgements

We would like to acknowledge the farmers; Denis & John Crowley, Co. Cork, George & Kenneth Williamson, Co. Wexford, Joe O’Donoghue, Co. Meath, and Teagasc extension officers; John Pettit, Ciaran Collins & Shay Phelan Teagasc, for providing farm management details.