Day 57 – Dr Elaine Ingham
It seems to be traditional now for me to put a map on each post, so here it is.
This is the only picture, so visual types might want to stop reading now.
Dr Elaine Ingham runs Soil Foodweb Inc and is world famous for her research in to [no prizes for guessing], the Soil Foodweb. She advocates that by getting the soil biology to be not only abundant, but also balanced, it is possible to make loads of money.
The method is fairly straight forward:
- Don't disturb the soil any more than necessary (no-till).
- Provide food for the bugs to live on (leave plant residues on the surface).
- Make use of properly made composts, and compost teas/extracts (no one makes proper compost in t he UK apparently).
- And finally, never use any inorganic inputs. This includes fertilisers, herbicides, fungicides and insecticides. To be clear, this is going further than being certified organic, because they too can use toxic inorganic chemicals on their crops.
As an example, we were shown a slide of a farm that grew oats conventionally. They yielded 3.5t/ha. This soil was heavily bacteria dominated, with almost no fungi. As a trial they treated some ground with compost and got it up to an even balance of bacteria and fungi. The yield, with no inputs, rose to 6.5t/ha. Elaine thinks that if the total amount of soil life was increased, but still kept balanced, the yields would double to around 13t/ha: "we have seen it occur". That's a big claim, which I think would exceed the world record oat yield. I will leave it up to you to decide if it sounds plausible.
One of the claims that I was particularly interested in was that "there are enough nutrients naturally occurring in your soil that you will never need to apply them". I've written about this before, in particular whether we need to be apply phosphorus fertiliser or not. Elaine put up a slide showing average concentrations of nutrients that are found in soil around the world. For phosphorus the figure was 800ppm. I don't know if that is what we have, but let's do some maths.
An acre of soil 6" deep weighs 1,000t.
A hectare of soil 6" deep therefore weighs 2,470t.
A hectare of soil 10cm deep weighs 2,470*10/15.24 = 1,620t = 1,620,735kg
1,620,735/1,000,000 * 800 = 1,296kg/ha of P
According to RB209 every tonne of wheat grain removes 7.8kg of P2O5 = 3.4kg of P
So a 10t/ha wheat crop will remove 34kg/ha of P
1,296/34 = 38 years of P for each 10cm of soil you are extracting from.
Dr Ingham claims that mature forests store more nutrients as wood each year that we ever take off the land through grain farming, and that they have been going for millennia without any additional inputs. This may be true, and if you consider that tree roots can be found going down to 7m+ in depth, that would be (38*70) 2,660 years of P. Sounds plausible.
But how deep do we delve in a annual cropping system? Our plants do not have centuries to put down deep roots. Dr Ingham says "wheat, corn, rye, oats, etc can, and should, put roots down to 10 to 12 feet in the first month or two of their life". I find it hard to believe that this is possible in a lot of situations - roots cannot grow into solid bedrock, and can they get into solid clay subsoils? Personally (with no science to back it up) I would be surprised if we get much more than a meter down, which would give us (38*10) 380 years of available P. But this also assumes that it is possible to extract right down to 0(zero)ppm. If you believe Neil Kinsey, this is not alway the case, so that may be overstating what is actually achievable. Of course, on the flipside, we may have 3,000pm of P in our soils, which would certainly mean there is a lot about. It needs testing.
One of the big benefits touted is that with healthy soil rotations become unnecessary. For centuries farmers have rotated crop types to stop pest problems building up. However, there are many people who believe that the longer you grow a particular crop, the more the soils becomes suited to it, and the more productive it will become. The problem is in reconciling these two opposing points of view. Dr Ingham thinks rotating crops is crazy - why go to the hassle of getting the soil working right for one species only to go and shake it all up again? [These%20guys]These guys found that wheat yields increased when grown conventionally, which they put down to increasing populations of nitrogen fixing bacteria living free in the soil (There are three types of bacteria that fix nitrogen, only one of which lives in the root nodules of legumes). It's an interesting idea, and one that would be incredibly convenient if it could be made to work.
The key is in the compost. As I said earlier, she reckons no one over here does it properly. It is critical that at no point anaerobic bacteria can be allowed to flourish, and that means turning the pile within the first few days (or even hours) to keep the temperature below 75C at all times. If done properly it will be finished after about 3 weeks, and will contain large numbers of all different types of soil life.
Once the soils are balanced, the pH will sort itself out (it does not want to be much higher than 7, otherwise nitrogen hangs around as NO3, which weeds love), plant pathogens never get to high enough levels to cause problems, nutrients will be made available to the plant, and weeds will not grow. This last one I find hard to believe. The theory is that different succession level plants have different biology niches, and so if you tailor your soil for your crop, nothing else will grow. But there are some weeds which are very similar to our cash crops, and I bet they would grow in the same conditions. It would be good to be wrong.
The recipe to "convert" your farm is straightforward. Before drilling your crop apply compost at around 10t/ha. Next drill your seeds, which have been soaked in compost extract and then dried. When the seedling has emerged spray with compost tea 3-4 times at 3 week intervals. That's it. 0-20% yield increases, with effectively no inputs.
How does the saying go? If it looks to good to be true...[probably]...
@dontknowanything blogs on www.ooofarmer.wordpress.com