Denis Burke is dairy farmer in Kilmain, Co. Mayo. He milks a herd of Holstein Friesian dairy cows. The 120 cow herd is a high-producing herd, milking on average 8,500L and 650 kg of milk solids.
The Kilmain farm has a mixture of soil types with dry limestone land rolling onto high organic matter soils. Denis talks about the different management strategies in maintaining these contrasting soils. He has exceptional soil fertility on-farm and is a testament to his nutrient management and exceptional grass swards.
Denis recognises the advantages of maintaining a healthy soil both for his farm production and profitability – and also the biology that lives beneath.
Through the adoption of the Grassland Agro/Aurivo soil sustainability programme nutrient planner, Denis adopted the expertise of his local Grassland Agro technical agronomist, Liam O’Donnell, who has developed a bespoke fertiliser plan to suit Denis, his farm and his specific system.
Slow release nutrients
Denis has been using OPTIGRASS speciality fertiliser for a number of years now. He recognises the impact the phased released form of nitrogen (N), and slow released form of phosphorus (P), has had on improving grass quality and soil fertility indices.
The slow released phosphorus has increased phosphorus availability and efficiency, and had a positive implication on grass quality, rooting and early tillering. The marine calcium and biostimulant component has had a positive impact on maintaining a healthy soil and reducing soil acidity.
Liam recently assessed soil structure on Denis’ farm using the GrassVESS technique, and diagnosed evidence of subsurface compaction on a few select paddocks that Denis highlighted as being poor grass growers. The poor soil structure is indicative of the poor fertility status on these particular paddocks.
As a measure of mitigating these subsurface problems Grassland Agro have advised the implementation of particular products that may help alleviate compaction, and also the implementation of certain cultivation practices when carrying out a reseeding programme.
Soil Health has a major influence on farm productivity and overall soil processes. Soil is often referred to as the earths natural filter, purifying the water that filters through it and eventually reaches a waterbody. It is essential that overall soil health is maintained in order to increase nutrient efficiency, agronomic output and reduce nutrient losses.
Some key steps can be undertaken to achieve optimal soil health.
- Check soil health
- Avoid soil structural damage
- Ensure sufficient Organic Matter levels
- Improve biodiversity
- Ensure targets are achieved regarding nutrient levels in soil
Checking soil health- Grass VESS
As part of the Aurivo/ Grassland Agro Soil Sustainability programme, our technical agronomists will be assessing soil structure on-farm using the GrassVESS technique developed by Teagasc.
Grassland Agro has developed a phone App for its technical agronomy team that will soon be available to everyone. This technique allows for the assessment and scoring of soil and root structure using an infield evaluation – using just a spade and ruler.
Although the GrassVESS technique does not test for soil biology populations it allows for the visual assessment of the soil habitat, including colour; structure; plant rooting patterns; and the abundance of larger soil organisms such as earthworms, which are all primary indicators or good soil health.
Diagnosing problem areas and prescribing management strategies to alleviate problems are crucial. The accumulation of surface water, mottling in soil horizons and compaction, are all indicators of poor soil structure and porosity and have detrimental effects on soil biology populations.
Grassland Agro have also developed a soil test to analyse soil biological activity. This test develops a soil health score and indication of potential of N mineralisation. By analysing the soil biological health score and GrassVESS soil structure in tandem, an overall soil health score can be developed for your farm.
If you would like to know more about these soil tests, please contact your local Grassland Agro technical agronomists or email: [email protected].
Avoiding Soil Physical Damage
Physical soil damage has adverse effects on the habitat for soil biology and micro-organisms, as well as their accessibility to a food source. Air, water and nutrients are essential to support a healthy soil biological ecosystem and maximise agronomic output.
Soil biodiversity can be largely effected by soil erosion; and the loss of soil organic matter has detrimental effects on all soil processes. Similarly with soil compaction, soil porosity is reduced, creating an environment with no air and a reduced ability of the soil to filter nutrients, causing a greater risk of nutrient runoff. This also creates an environment in which soil biology cannot live.
Avoiding machinery or animal traffic when soil conditions are poor, and maintaining a healthy vegetative cover in the ground, are key management strategies to help reduce the incidences of soil compaction.
Liming is an important management strategy in buffering the soil and creating optimal pH conditions for soil biology. Liming can also create structure in the soil through the addition of calcium or magnesium based liming products.
Calcium is a larger molecule than magnesium and therefore can create a better structure in finely textured soils. Finely textured soils (e.g. high clay content) are usually more acidic in nature also, by adding a calcium based liming product the calcium ions are creating a more porous structure.
However on sandy based soils, the addition of magnesium can create a more tightly knit soil, reducing the pore space and reducing leaching potential. The optimum ratio of calcium: Magnesium on clay soils is 7:1 and 3:1 on sandy soils.
Soil Organic Matter
Maintaining a healthy level of soil organic matter is critically important in the physical, chemical and biological health of any soil. Although Irish soils generally have high levels of soil organic matter, they can be quickly depleted on tillage and silage fields. Soil organic matter helps provide structure to the soil, it aids in the storage of nutrients in the soil and also offers food for the soil biology to live on.
A healthy level of good soil organic matter through the application of organic manure, adopting crop rotation strategies, incorporating crop residues and maintaining a root system is very important in providing an environment for biology to live and flourish.
Mixed Grass Species
Agriculture in Ireland is predominantly a grass based system, with greater than 60% of agricultural area under grass lays. This proportion of grassland contains limited species, however much work and focus has been put on increasing the diversity of species in grass lays.
Increasing the number of aboveground plant species not only results in an increase in biodiversity above ground, but also results in an increase in the food source available to soil organisms below ground, increasing soil biodiversity and the subsurface food web – which is essential in ensuring a healthy and habitable eco-system for soil biology to grow and flourish.
The new REAP pilot project will aim to improve the environmental and biodiversity status of land into the future and we plan on safe-guarding the health of our soil, the most vulnerable and valuable resource we rely so much on.
Similarly with the National Climate Action plan, farmers complying with nitrates derogation must include clover in their seed mix when incorporating a new sward. It is important that optimal soil conditions are maintained in order to maintain the N fixing bacteria in the soil.
Strategic Fertiliser Application
An overload of nutrients beyond plant requirement can have negative effects on soil biology. It can cause certain soil microorganisms to become dormant or inactive in the soil as soil conditions become unfavourable.
When land is depleted of nutrients through offtakes such as crops and silage and not replenished, essential nutrients and the food supply for micro-organisms will be limited, particularly surrounding carbon. When nutrients are unbalanced, it has a negative impact on all the processes we take for granted and expect soil biology to carry out, e.g. the decomposition of plant residues, N fixation and mineralisation.
Grassland Agro will develop a personalised fertiliser plan for your farm to ensure habitable conditions for all soil processes through the implementation of a liming and fertiliser programme with the aim of reducing nitrogen inputs in compliance with new measures of the climate action plans 20% reduction by 2030.
For more information, visit the Grassland AGRO website by clicking here.
