Weatherproof farming
Hot summers are an opportunity not a threat according to regenerative agriculture consultant Niels Corfield, but only if soils are healthy. Niels explains why he believes poor soil health is a threat to UK dairy and how on-farm monitoring is central to improving productivity and making farms weatherproof for the future.
My work on weatherproof farming is based on monitoring soils across over 100 farms throughout the UK, evidenced by simple spade pits and infiltration tests.
Comparing tests taken in the field with an area ‘out of management’, such as the margins or under a hedge, eliminates the influence of factors relating to soil type, leaving only ‘management’ as the major influence on results.
I’ve seen infiltration rates in the margins up to 100 times quicker than in ‘managed’ areas. It is this ability to capture and store water which gives the potential for dramatically increased grass production during the warmer months.
Soil moisture levels
Pastures need to be responsive to rainfall as weather patterns become increasingly unpredictable. Rainfall is less dependable with the certainty of ‘April showers’ gone; those short bursts of intense rain just as temperatures are increasing were the perfect way to ‘rehydrate’ the ground after a cold winter.
But wet winters and hot, dry summers are becoming the norm – and heat drives growth. So, these ‘new’ summers are actually a significant opportunity if the winter’s rain has been translated into a healthy soil moisture level.
Conversely, if soil moisture is low when the growing season begins, water becomes the limiting factor and dry conditions become a threat.
It is easy to assume the presence of standing water in fields during the winter indicates waterlogging, but this is not always the case – it could be an indicator of compaction.
From my own on-farm observations, I believe issues of compaction are driving the droughts we are seeing rather than the weather.
Irrespective of soil type, we have lost the aggregate structure of our soils due to the impact of our management practices. Even in the heaviest soils in the middle of winter, 2-3 cm of water can disappear in seconds when soil structure is good.
How to improve soil structure
Moving away from set stocking to a rotational grazing system is the most important change we can make in grazing management. To support this, I also advise a three-pronged approach to improving soil crumb structure, comprising mechanical, mineral and biological interventions.
1. Mechanical: Bottom up
Dry soils behave like ceramics, shattering across a wide area from one point of impact.
Mechanical interventions aim to cause maximum ‘shatter’ of soil at depth. By using the kinetic energy of roller-type slitters like Aerworx in a rotating action rather than a subsoiler’s pushing and pulling motion, this outcome is achieved quickly and with minimal horsepower.
2. Mineral: Middle out
The use of gypsum flocculates the soil. The large-sized calcium molecules force soil particles to open while the sulphur can bind with and remove excess magnesium, often seen in high levels in ‘tight’ soils.
3. Biological: Topdown
The aim of biological interventions is to increase turf depth and density using deep-rooting plants in multi-species mixtures. Attention is also given to the nutrients able to stimulate root growth, with phosphorus, boron and sulphur, as well as seaweed and humic acid, all having documented modes of action.
Although multi-species seed costs are higher, selecting diverse mixtures reduces the need to reseed so often in the long term – do it well and do it once!
Last year’s dry summer undoubtedly proved the value of sward diversity, with herbal leys the only fields of green in many areas. They need to be sown using a high seed rate with full cultivation and moisture to give them a good start. A maximum of eight species is showing good results, but each species group must be represented, ie. herbs and legumes in addition to grasses.
Milk from forage
Increasing milk from forage is an important part of First Milk’s regenerative farming plans. Making better use of rain to grow grass is a central part of achieving this goal, as well as addressing the need to reduce a farm’s carbon footprint through reduced nitrogen use.
The natural (and free!) elements available to us – air, water, sun and soil nutrients – can all be capitalised upon when soil health is improved. I estimate current water use at around 20% efficiency on most dairy farms. If we capture more moisture in our soils from the winter, we can drive greater grass growth during the summer. With the current hot spell we’re seeing, we could be breaking records by now!
Summary
- Maximise production from the free resources of air, sun, water and soil nutrients.
- Heat and sun drive growth better than anything out of a bag as long as water isn’t a limiting factor. Water is required for yield.
- Production is tied to rainfall. Use efficiency for rainwater is the same as other inputs. Historic management of soils can lead to a use efficiency of 30% or less.
- N-inputs don’t work without soil moisture.
- Compacted soils poach and poached ground goes hard before burning-off quickly.
- Burning-off is therefore a compaction issue.
- Healthy soils absorb water and retain it for warm periods.
For more information: nielscorfield.com