SOM #1: managing soil organic matter and carbon for optimal productivity and to support sustainable farming
NRM
Agriculture
Environment
Taking care of soil organic matter (SOM) is critical because it plays a huge role in the overall quality of soil. It helps improve the functioning of important natural ecosystems, increase the soil’s capacity to produce food, provide flood mitigation, and protect water and air from potential pollutants.
As an industry we must plan how we better manage soil and organic matter now and into the future, implementing strategies that are sustainable and adaptable over the longer term.
The importance of a soil plan that includes SOM and carbon management
A soil management plan used to be a bit of a box-ticking exercise, but these days it’s crucial that we make a proper assessment and take it seriously. This is particularly important due to the requirements of the Sustainable Farming Incentive (SFI). It doesn’t have to be a big job, but it is an important job.
Assessing the physical characteristics of land parcels, in terms of the topography and their natural features, helps us understand the risks of damage and loss of functionality when managed in a not-such-a-good way. We have all seen the tsunami of soil and water running off bare fields over last autumn/winter and throughout spring this year when crops were harvested late in less-than-ideal conditions, and when winter crops either poorly established or were not drilled at all!
Soil type and its texture indicate the likelihood of erosion risk. How free-draining a soil’s texture is, the proximity to surface water, and how steep sloping fields are are all physical characteristics that need to be considered when deciding how we manage our farmed land.
Higher SOM levels can prevent crop productivity from declining for a time, but if it is not maintained over the longer term, then the important relationship between organic matter and soil functionality nosedives. SOM and soil carbon content (SOC) are rapidly becoming one of the most important management KPIs in crop production, and when soil becomes degraded it can no longer support the vital processes crop productivity relies on. This is why SOC is becoming an essential indicator of a farming business’ overall viability and production potential.
Additionally, the wider advantages of adopting management practices that build and protect SOM and SOC at the farm level can’t be ignored. Improvements in SOM and SOC are linked to a multitude of benefits, such as soil pore connectivity within soil aggregates. Soil pore connectivity enables the movement of nutrients, water, air, and gases, and creates an important environment where microbial and fungal communities can thrive. A fully functioning, biologically thriving soil leads to great outcomes for food production because it improves nutrient cycling and therefore better use efficiency by plants. It also improves water dynamics (i.e. moisture retention and infiltration), which all leads to a more resilient farming system and, in turn, makes space for natural systems.
Nature is a self-organising business and works it all out if we give it the chance to. The less interference, the more giving our natural systems become.
Is one farming system more environmentally friendly than others?
Work being undertaken at Rothamsted Research in Devon over the last 6-7 years has been focussed on the impact of changing from a livestock pasture system to an arable system on the health of soil and the environment. This work recognises that livestock agriculture contributes to climate change through the losses of GHGs to the atmosphere, but if we reduced or possibly eliminated our animal numbers, then what do we do with the land they would be utilising?
The obvious alternative is arable agriculture: cultivating land to produce crops that humans can eat.
We know the benefits of maintaining pastureland from a SOM and SOC perspective. Cultivations over time reduce the capacity of a soil to retain organic matter, and these large, longer-term experiments are in the business of quantifying the initial decline, when we move from away from pasture based agriculture.
Long-term (170 years) experiments conducted by Rothamsted Research in Harpenden have well documented the benefits of adding back organic materials to cultivated arable land. This is due to the clear benefits these materials bring to overall soil health, organic matter, and carbon.
If you want to read for yourself about this valuable resource, click here to find out more.
It strikes me that the project at North Wyke might end up showing that throwing the baby out with the bath water results in poorer outcomes for climate and our environment if we switch entirely from livestock pasture-based systems to arable agriculture. I do not want to see an environment without grazing animals, but there is always room for improvement in terms of how we currently manage our livestock systems and as a society consume meat-based foods. Click here and watch a video about the project and what the researchers hope to achieve.
NRM: here to help
Measuring soil organic matter and soil carbon couldn’t be easier. NRM’s CarbonCheck services include soil organic matter analysis to help you qualify for the SFI, improve soil health, and get a head start on your carbon capture journey.
Click here to contact us directly or speak to your adviser for further information.
References
https://www.rothamsted.ac.uk/national-capability/the-long-term-experiments
https://www.youtube.com/watch?v=mSlHiNmn3Ls
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