To cultivate health on the farm, in our food and in a larger environmental way, we have to start with the soil. GSF market garden is about to enter its 4th growing season and prior to this the farm was not managed organically. One of the fields used for veg growing was intensively grazed by horses and the topsoil is shallow, compact and lacking in soil life. The compaction is observable in the thick cover of dandelions, a plant which thrives in anaerobic, collapsed soils – these robust plants are notably repairers of soil structure with their large tap roots. Compaction can also be seen in the way that water sits on the land and by the moss that thrives, in place of a more diverse sward, on water-logged, disturbed ground. The low levels of soil activity are observable above ground in the layers of thatch, ‘undigested’ organic matter sitting on the soil surface, because the process of decomposition is disrupted. There are surprisingly high levels of organic matter in the soils but not in a form that is accessible to plants as the process of breakdown into humus (the final and stable state of soil organic matter) is not complete.
Healthy soil microbiology is the unseen crowd that props up a larger thriving ecosystem and is essential for improving soil structure, nutrient cycling, water holding capacity, carbon sequestration, decomposition, disease suppression and, ultimately, plant, animal and human health through more nutrient dense foods. We are trying to improve the soils in the market garden – and across the farm – as we observe its various states and learn how to support the underfoot biosphere better. We have been testing the soils (with the help of Soilmentor) across the farm twice a year on regular sites; this is in part to prioritise observing and understanding the soils but also to track the change that we will hopefully be making! In addition, Holly‘s report as part of her CREATE course with Nicole Masters provided great insights and suggested remedial actions we could take.
In the market garden we have made certain management decisions with soil health at the fore. Firstly, by trying to keep the ground covered as much as possible with a diversity of plants. Green manures and cover crops can be challenging to fit into an intensive, complex growing system, as you need to make sure the diversity you are adding does not have a negative impact on your cash crops. Timing is key to getting green manures to work as you want them to, whether that is after a crop has finished or as an understorey to cropping plants. If you sow a companion cover crop too early, it may out-compete your cash crop, or if you let it go to seed this may affect subsequent crops in that area.
For example, we sowed white clover in some polytunnel pathways (which was mowed regularly) as a ground-cover trial; the polytunnels are an obvious place to start as, without ground cover, the soil in there will quickly become hard and dry. The clover, as well as being a nitrogen fixer, did a great job at improving the water retention ability of the soil, which in turn will better support soil life and the adjacent crops seemed to thrive as a result.
We also added a wild pollinator mix under some of our tomatoes and intercropped the aubergines with basil and Celosia – unfortunately the aubergines intercropped with basil were soon significantly behind those that weren’t, so the basil ended up coming out (the aubergines then quickly caught up so no harm done). We have had some successes and some failures this year and have a lot more to learn on keeping our soil covered in a way that works for our crops and the efficiency of the garden throughout the season.
Another management choice we have made in the market garden with the aim to increase soil health is minimal cultivation, or in the case of the no-dig beds, none at all. We are establishing a system of using heavy duty blackout sheets to tarp ground in preparation rather than rotavating it where possible. Here we mow and then cover, so there are roots in the ground and a mulch of plant material which feeds soil life. We are planning to start biopriming (pre-soaking) our seed with microbial extracts and spraying more bio-active solutions onto the land, to hopefully grow populations of beneficial organisms in the soil. Our soils are currently deficient in fungal activity, which we hope to boost with wood chip compost and extracts made with material from the healthier, wooded (and uncultivated) parts of the farm.
We have a long way to go still but are slowly becoming more versed in recognising what state the soils around us are in and how we can have a positive impact on them, which is essential for the future of our farm, communities and planet.
Athene Peel
