Elaine Ingham (2015). The Roots of Your Profits

Elaine Ingham. 2015. The Roots of Your Profits. Video. In 'Oxford Real Farming Conference (6 – 7 January 2015)'. Retrieved from youtube.com/watch?v=x2H60ritjag.

In this ca. 90 minute keynote presentation aimed at the farming community, soil microbiologist and founder of 'Soil Food Web Inc.', Elaine Ingham, gives an overview of the different members of the soil microbiome, and their roles and importance to healthy and robust plant growth. This, and the ways in which the microbiome interacts with their plant neighbours to tailor nutrient uptake are described. The slides also provide examples and (quantitative) characterisations of the different successional environments, together with the results of field trials and photographs showing the effect of compost teas and inoculants upon root growth, nutrient uptake and watering needs (within a ridiculously short period of time).

• 10:57–14:16: On exudates and the interaction between plants and their microbiome (including nutrient retrieval and protection against detrimental bacteria and fungi)
• 16:31–19:25: On the conversion of soluble forms nitrogen, phosphorus and sulphur into gasses under anaerobic conditions, the role of aerobic bacteria in building micro-aggregates and retaining organic nutrients, and the detrimental effects of inorganic fertilisers
• 19:36–21:20: On the role of fungi in the formation of macro-aggregates; on soil compaction and its effect on water sequestration vs erosion
• 22:01–25:00: On nutrient cycling, i.e. the release of nutrients captured in bacteria and fungi by protozoa and fungal-eating nematodes and micro-arthropods
• 26:08–27:00: On the next trophic level, or how predatory nematodes and macro-arthropods 'manage' the fungal-eating nematodes and micro-arthropods, and how earthworms, spiders, birds, etc. manage them
• 30:54–31:46: On how plants use their root exudates to signal which nutrients they require, and the speed with which their release can be controlled (on the order of 3 seconds!)
• 32:33–38:42: On nutrient retention, or why it is that one doesn't need to go in and replenish the soil after crops have been harvested (hint: it's because the micro-organisms produce the acids and enzymes that break the (insoluble) sands, silts, clays, rocks and pebbles down, convert them into plant-available forms, and secure them against leeching, etc. — if they're there)
• 38:42–39:04: “When you think about the fact that that soluble pool is less than 1% of the total nutrients that are actually present in your soil, you can see where you could be led astray if the only thing you're told about are the soluble nutrients present in your soil.”
• 39:59–40:21: “And as long as you understand that the reason we've been put into that chemical trap is because we've destroyed the biology in the soil. The only reason the Green Revolution works is because the life has already been destroyed. They're not growing on soil, they're growing on dirt.”
• 44:12–45:05: “We need to make certain that the proper balance of these organisms [is] present in our soil and then forget about the inorganic fertilisers. Forget about pouring manure on your soil. A little bit of compost — half a tonne of compost every couple, three to five years. That's, maybe if you need it, that's what you should be thinking about. Will that reduce your workload? Just a little. So, those soluble nutrients, we need them in small concentrations instead of putting the whole growing season's set of nutrients on the soil at the beginning of the growing season, and of course, 80% of those leech, are gone, they damage everything downstream.”
• 45:06–46:18: “So really, when you think about this, sending a sample of soil into a soil chemistry lab makes no sense. That's not the important information. The important information is what's your biology? Do you have the organisms to tie up your nutrients? Do you have the organisms that will then release those nutrients right in the root zone, and not away from the root where the plant doesn't need it. If you really want to monitor nutrients, what you need to be monitoring is your plant tissue. So a plant tissue test will tell you what your plant is actually getting. So you can go into the scientific literature, you can look at the studies that have been done ... comparing soluble nutrients present in the soil with what's actually in your plant. At any point in time, what's the relation between the plant tissue nutrient concentrations and the soluble nutrient concentration in your soil? There is no relationship at all.”
• 46:38–47:41: On the definition of a 'more-on' farmer (fixing the biology vs continually purchasing and applying inorganic fertilisers
• 47:54–48:14: “I can take you to any forest system, and I can show you that the phosphorous concentration in that forest is 0.0001 ppm, but you look in the plant tissue and there is excess phosphate present in the plant tissue of the plant.”
• 48:34–50:51: On conventional models of nutrient availability vs soil pH, plant-preferred soil pH levels, and how plants actually control pH levels right around their roots (cf. pH levels averaged over a field on a larger scale), sometimes creating vastly different environments at different locations simultaneously
• 50:52–52:13: On soil vs dirt, and how, through the uptake of organisms in the former, rain (and other) water is effectively 'filtered'; this is in contrast to dirt, and especially dirt with compaction layers, where in-solution nutrients are not taken up, and thus taken away with the water
• 52:41–59:59 and Slides 10–12 in the presentation: Examples of bacteria, fungi, aggregates, protozoans, nematodes and roots (and the characteristics of beneficial vs detrimental species), as seen through a microscope
• 59:59–1:16:22 and Slides 13–15 in the presentation: On how the presence of micro-organisms and bacteria:fungi ratios can be used to characterise soil biological succession; also, where different types of crops (and plants, more generally) fit within this successional continuum
• 1:16:23–1:18:21 and Slide 16 of the presentation: On why it is, given the succession of biomes, that the whole world isn't one big forest (hint: because of natural and anthropogenic disturbances)
• 1:18:25–1:21:01 and Slides 17–18 of the presentation: Photographic examples of soil stratification due to compaction and the resulting root confinement; also the effect of this stratification upon water stagnation
• 1:21:01–1:23:45 and Slide 20 of the presentation: On how deep root systems can penetrate healthy soil — a few inches (for veggies) to a few feet (for trees), according to conventional / agricultural wisdom, vs 4+ feet (for common rye grass) to — and how this affects their resilience to drought conditions, etc.
• 1:27:28: Start of Q&A
  • 1:29:54–1:34:00: On whether BRIX (the spectral analysis of plant sap) is a good indicator of soil health (and/or the total amount of solids in the sap as an indicator of a plant's photosynthetic activity, when corrected for temperature, time of day, etc.)
  • 1:34:11–1:35:58: On how crop rotation isn't necessary if you have the right biology in the soil