– Review by Clive Bright
Following the momentum of the Biological Farming Conference in November 2018 (which was designed to be an inclusive, broad introduction to the many facets of functioning soil health); there was an appetite among the delegates for more in-depth information. NOTS decided to invite Dan Kittredge back for an advanced two-day workshop on the 7th & 8th of January 2019. It was hoped that 30-40 would attend, but the final tally was closer to 60 – again emphasising that the tide is turning.
Dan is a horticulturist, and although he references his personal experience, he speaks in broad strokes, the principles apply regardless of the production model. Together with Dan, there was a panel of Irish contributors with the goal of giving Irish context to the discussion. The crowd where diverse many of them experts in various sectors of both farming, growing and research, (both organic and convention). There was even a strong contingent of large dairy farmers, drawn no doubt by panel contributor John McHugh, (organic dairy farmer) famous for his inspiring conversion from large intensive dairying to a low-input organic model; involving mob-grazing his dairy herd on species-rich herbal leys. John is also an outspoken contributor to Agriland (on-line agricultural news portal) with many articles on his farming philosophy.
Also on the panel was Irish grower Jim Cronin, Thomas Fuohy represented tillage (min-till and cover cropping and diverse rotations), and although I sat for beef, I echoed John McHugh as another mob grazing grassland farmer.
It was an intense interactive two days of learning and discussion – teasing out ideas and practical routes to applying Dan’s knowledge in an Irish context.
Dan is a keen advocate of re-mineralising soils an addressing trace element deficiencies, such as boron and cobalt together with major ones like sulphur and calcium. He advises that balancing the suite of elements is “an important piece of the puzzle to get your soil to it full biological potential, and establishing the microbial pollination to cycle those nutrients and therefore grow nutrient dense food”.
He anchored his whole presentation around five foundational factors of healthy soil: Air, Water, Food, Life, Minerals. “The first thing to address is water – no water, no life – don’t water the plants, water the biology in the soil. If you cannot maintain constant hydration throughout the growing season, re-mineralising is a wasted effort”.
This point was illustrated best when demonstrated by Jim Cronin when he showed pictures of some of his kale plants that had succumbed to ringspot fungus*. Jim explained that he grew disease free brassicas in the same garden later that season. The question was: what caused the first crop to be susceptible to ringspot? Two observations were made; first, that other plants in the picture had slightly lighter green younger leaves which is symptomatic of a Sulphur deficiency. The second observation was that the soil was dried and had no cover/mulch. We learned that the ring-shot had occurred during the summer drought (2018). The dry conditions stressed the plant.
Dry soil causes the soil biology to stop functioning and dramatically limits the plant availability of Phosphorus and Sulphur. Ringspot is especially virulent in sulphur deficient crops, in fact, it was noted that the conventional fungicides for this infection include sulphur as a dominant ingredient. The moral of the story was that if the soil was kept hydrated, it is very likely the infection would not have occurred, because under normal conditions the plant available sulphur levels are adequate, the foundational problem was a water deficiency rather than a sulphur deficiency.
Many of the common biological ideas were discussed such as keeping the soil covered with mulches, limiting tillage to preserve the soil structure and beneficial fungal networks.
Dan stressed that inoculating seed with a diverse biological inoculum was the “best way to get the big bang for your buck” suggesting that it was like colostrum for the plant.
These inoculums can be purchased, but he also described methods to make your own by taking a walk with a bucket aiming to visit as many habitats as possible, field, forest, river bank etc. find plants with the shiniest leaves and take some soil from around their roots. Mixing these soils in the bucket which harbour a vast range of biology, adding water and stirring before using it to drench the planting holes.
Once the soil minerals are in balance, Dan suggests keeping things in check by adding rock dust (quarry spoils) from a granite or basalt quarry. It was noted that the availability of this material in Ireland was very limited because most of the bedrock and therefore quarries in Ireland are limestone quarries. The main granite seams are in the south-east and basalt in the far north in Antrim which means the haulage cost for most, would be prohibitively expensive.
Another cheap source of a broad spectrum of minerals is sea salt or rock salt. Dan advises this can be dissolved in water and spread at up to 75lbs (34kg) per acre as a foliar spray. The hesitation from the audience was voiced, that salt on soil was understood to be a bad thing. Dan reassured that this was a relatively tiny amount compared to what could cause any damage. He made the analogy of adding salt to soup, too little does nothing, too much and the soup is horrible but at the right amount and it brings the whole soup together.
Toward the end, people wanted a suggestion of something that could be done at the start of the growing season. In the spring when light levels are low, photosynthesis can be simulated by a foliar spray of sugar, (organic molasses @ 1gal or 3.7L per acre) to encourage early growth and therefore facilitate more photosynthesis. The molasses can be added to the sea salt and delivered in a single application. Dan confessed that he calls this cheating; in that, it grows better crops than if they were left to grow of their own devices. He says it is the sort of cheating that is also for the greater good, stimulating photosynthesis with the addition of minerals allows for more mineral and carbon cycling to occur therefore it has the dual effect of enriching the soil and the crop.
Other take away messages were how two simple and relatively cheap measuring/monitoring tools could be used effectively to aid observation in the field – Refractometer (Brix meter) and a soil conductivity meter. If a plant is growing in ideal conditions and is not stressed, the plant leaf sap should be at a Brix reading of 12 early in the morning. Brix 12 can be difficult to achieve, but it is the goal as it correlates directly with the health and nutritional density of the plant.
The conductivity meter shows the general nutrient availability in the soil; dry soil will have a low reading but so will a wet soil with low mineral availability. A soil with adequate moisture and plant available nutrients will have a high reading. Both the refractometer and the conductivity meter are tools to help you monitor when things are going well and can be an early warning of a problem. For example plants with a low Brix are more susceptible to disease.
The course was jam-packed with information, simple ideas and concepts all cleverly delivered in Dan’s well-honed stories, logical metaphors and real-life examples. His raconteuring nature makes Dan’s wisdom stick, and as the days go by since the event, those stories and their messages still churn in my mind.
Watch Dan’s short lecture on Soil Inoculants below: