Don Somers runs a tillage farm in Oylgate, Co Wexford, and farms 178ha collaboratively with his uncle James. Don grows mainly winter and spring cereal crops, with break crops such as oilseed rape and beans. Soils types across the farm range from free-draining to moderately draining.
Crops have been established with a minimum tillage operation since 2018, which helps to reduce costs, increase field work rates and improve soil health. Don is also participating in the Teagasc Signpost Programme to demonstrate and implement climate smart options to reduce nutrient losses to the environment.
Crops, rotations and markets
A range of quality cereal grains, oilseeds and beans, which are mainly for the Irish feed market, are produced annually. Break crops bring the added advantage of higher yields in the following cereal crops. For example, winter wheat can yield up to 1.5t/ha more following break crops such as oilseed rape.
A typical crop rotation on the farm would be winter oilseed rape or spring beans, winter wheat, spring barley, winter oats, winter wheat and winter barley. Break crop selection is dictated by soil type, where the break crop fits in the crop rotation and soil conditions at the time of drilling.
Soil fertility status
Improvements in soil fertility have been achieved over the long term through a combination of optimising soil pH, applying additional phosphorus (P) and potassium (K) to lift soil indexes, balancing P and K applications based on grain yields, the application of organic manures and the use of cover crops to mitigate against P losses.
In 2023, P and K application rates will be tailored to balance crop and soil requirements.
Don is moving away from traditional N, P and K fertiliser blends in favour of straight fertiliser products such as Super-P and Muriate of Potash. Figure 1 shows that 59% of soils on the farm are at optimum soil pH, P and K compared to just 18% nationally for tillage farms.
Don’s aim over the next few years as a Signpost farmer is to optimise soil fertility to 90% through continued fertiliser planning.
Crop sensor and variable rate N technology
To improve crop N utilisation, Don has conducted crop N sensing on a number of fields to establish the variability in his crops in 2022 for the first time. An NDVI nitrogen (N) sensor that measures plant colour was set up on the tractor used for the main fertiliser spreader.
Chemical fertiliser N was applied using variable rates across these fields based on sensor readings received as the tractor passed through the crops. For the final N split on a field of winter wheat, 50kg N/ha was recommended to be applied at GS33/37.
According to other uses of the sensor and variable rate technology, at this final application timing to the crop it is a good time to try to balance total crop N required based on crop colour. At application, the N rate ranged from 42-65kg N/ha. The final grain yield for the field was 11.7t/ha and grain yield ranged from 9-13t/ha based on the yield map.
Measured grain proteins varied across the field from 7.08% to 8.4%, with an average grain protein of 7.82%. Overall, the N efficiency calculated was 89% (see Table 1), which is well above the national average of 65% for tillage crops in Ireland.
The autumn of 2021 was very favourable for excellent crop establishment, plus low winter rainfall reduced N losses over the winter period. A cover crop was grown and incorporated into the soil before planting.
These two factors reduced N leaching over winter, making more soil N available and resulting in high grain yields. The aim in 2023 will be to further utilise this technology to refine in field N application.
Cover crops and soil health
Options such as applying organic manure, sowing cover crops and straw incorporation are implemented to add soil carbon to the soil to feed its biological life and subsequently improve soil health. Cover crops are now part of the farm crop rotation and bring many benefits; adding valuable soil carbon, retaining soil N and P and making soil more friable and workable.
The aim is to sow cover crops as early as possible once crops have been harvested to maximise N uptake and cover crop dry matter production. Early cover crop mix consists of phacelia, vetch and clover. Later drilled cover crops include oats, rye and phacelia. Initial Teagasc Signpost studies on covers show that in 2021, cover crops took up between 27-64kg N/ha over the winter.
Diversifying into agri-environmental schemes
Don has applied to participate in Agri-Climate Rural Environmental Scheme (ACRES) as it is very attractive for his farming system considering that a number of measures within the scheme, including minimum tillage and cover cropping, are already practised on his farm.
To further enhance farm biodiversity, the tree planting option was chosen.