Monday, October 26, 2009

Who eats who?

Kristine Nichols, Microbiologist, Northern Great Plains Research Centre, Mandan, ND

Kris Nichols is part of an elite group of people - the world of soil microbiology is pretty small. Some of her most recent work has been investigating Glomalin. This is a glycoprotein which was found to be a major component of soil building organic matter. Basically for the layman, Glomalin is something protects something else that transports soil nutrients and may be very important in building soil carbon!

As we were talking, Kris said she always analyses her work from the point of view of her Dad who farms in Minnesota. "I always look at my research and I ask myself - is this something my Dad could understand and apply on his own farm?" This is probably the reason that Kris is often asked to speak at no till and soil conferences packed with farmers, a scientist with the ability and desire to make sure her research can be practically understood and applied. Thats good then, a research scientist with a bit of mud on her boots!

"My advice is to manage the soil environment as a first consideration and everything else will fall into place" says Kris. She said soil has historically been called dirt but to her what separates soil from dirt is organic matter. "We need more of this organic matter and again all these microbes are like people - they need food and shelter."

These are a few key things I picked up from Kris:

  • High clay soils need plenty of OM. Clay minerals bind themselves together and it is difficult to break their postive charge to each other. So you need to grow organic matter; this means clay won't bond to clay so much. This organic matter bonds the soil with microbial action and improves water holding capacity.
  • Suprisingly crop residue's in fact provide very little carbon to the soil. About 1%. Most carbon from crop residue never gets into the soil. The living plant and its roots contributes most carbon to the soil. 70% of Carbon produced by a plant should be in the soil.
  • There are limitations to conventional soil tests. We only measure plant availible nutrients not total availible nutrients. Plants do not operate in a closed system like this.
  • Why does manure tilled in show a decent crop reaction? - When you bury manure you feed one particular set of organisms and they utilise this food source very quickly. But they are only one set - after this food source has gone you will be left with famine and nothing for your other creatures. A balanced, varied diet is key.
  • Cover crops and crop mixtures are good because they release a variety of different sugars and energy sources which are used by a range of organisms. This will have positive impacts on soil fertility later on esp. with regards to providing or making nutrients availible - for free! These sugars have a positive effect on growth - when we talk about getting the soil to warm up in the spring it may not be a function of temperature thats important but the function of biological activity.
  • Pesticides and Soil: She ranks insecticides as the worst. Fungicides next and herbicides relatively harmless. That said even though microbes use herbicides as a carbon food source (for how else do they break down?) they can lead to an imbalance of what she calls aggressive "piranha-organisms." Ones which push others out of the way. The less the better.

There is so much more to say but it is much better communicated by Kris. There is a vid of her in the link. I left here with the feeling that the potential of soil biology is massive - its strange how small pieces of information can lead to a better understanding and a different way of thinking.

More on Kris:

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