[Terrapreta] Guidelines for Using Terra Preta

[Sean K. Barry]

Hi Richard,

"To me this is still an interesting research topic and is not ready for dissemination as proven agricultural methodology in the temperate zone."

This is an excellent point you make.  It suggests to me that great patience and heavy research and experimentation are required before making claims that "IT WORKS" about any soil management techniques, which are applied on worldwide basis.

SKB


  ----- Original Message ----- 
  From: Richard Haard<mailto:richrd at nas.com> 
  To: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Cc: Todd Jones<mailto:tjones at nas.com> ; Veronica Wisniewski<mailto:veronicaw at fourthcornernurseries.com> 
  Sent: Sunday, April 22, 2007 7:14 AM
  Subject: Re: [Terrapreta] Guidelines for Using Terra Preta


  Tom, Larry and temperate zone list readers.


  I have to admit that I am not reading all of the threads that come across this list but my comments below on Toms posting are addressed to those interested in the so - called terra preta phenomenon in soils in temperate North America.  


  I think it is way too early to state with confidence that the effect of charcoal in soil , in the temperate north has any effect other than a soil conditioner that sequesters, nicely, some carbon. My own idea of what we were doing here on this list is to encourage temperate NA readers to try the material and to study and discuss the scientific research on the  topic that is occurring in the global arena.



  On Apr 21, 2007, at 2:41 PM, Tom Miles wrote:


    Much of our discussion in the past few months has been to clarify what terra preta is and how it functions. There are clearly many misconceptions about charcoal, the qualities of charcoal, how it is made, how it can be used, and how it functions in different soils with different plants.  A useful product of this discussion and the ongoing research and field trials would be draft guidelines for the use of terra preta. I’m thinking of the kind of general information published by our extensions services. Eventually these will be developed by many organizations, including the IAI, but it would be useful to start drafting something here.


  My own view from here in the northwestern corner of the US where I have been farming the same tract of soil for 20 years is that I may have 'terra preta' already, even before I apply charcoal on to my soil.


   If you look at the recent comment by Christoph Steiner on the characteristics of the soils in the humid tropics of Brazil -


  On Apr 16, 2007, at 10:13 PM, Christoph Steiner wrote:
    Dear All,


    Most soils in the Amazon Basin have very low contents of inorganic
    nutrients. These are deeply weathered soils and the predominant minerals
    are iron and aluminum. Therefore most nutrients in Terra Preta have
    organic origin. Terra Preta fertility is linked to an anthropogenic
    accumulation of phosphorus and calcium associated with bone apatite, thus
    increasing the pH. Increased pH alters the availability of nutrients.
    Phosphorus, which is considered to be the primary limiting nutrient to
    plant production on the highly weathered soils of the humid tropics, could
    become available through fine root endomycorrhizal associations and
    through heterotrophic phosphate solubilising microorganisms, which are
    supposed to be stimulated by soil charcoal additions.


  I actually felt differently about my own farming effects on our farm soil before I started conducting soil analysis at our field and comparing the results to analysis of the new field on the same soil type that has never been intensively farmed. Our farming practice of raising bare root plant crops on our sandy loam soil could not be harder on soil organic matter because we harvest everything, roots and tops leaving, sometimes, the leaves of deciduous species behind to be recycled. Yet our soil organic matter is holding at 4 to 5% in comparison to 5 to  6% on the new soils. 


  I farm in a climatic zone where like the moist tropics precipitation exceeds evaporation and rainfall leaches the soil carrying away the soluble elements not captured by the microbes and plants into the water table.


  My soils are the product of glacial deposition and sediments carried by the great Frasier river system of British Colmbia, that formed our land during the post glacial period 10 to 15,000 years ago. In contrast to the moist tropics these soils carry large natural supplies of phosphorus, potassium and calcium in addition, our neighboring dairy farmers over the years have been spreading liquid manure to further cause accumulation of nutrition and OM. 


  My farm's limiting factors are some trace elements which can be easily controlled, water during our  normal summer  drought period which is a problem in our well drained soil, and soil nitrogen which is always in on the low end of the spectrum in both our heavily farmed field and our new field. 


  What then would I look for in my soils that would indicate a positive effect from the application of charcoal? In my case retention of soil nitrogen and improving soil water holding capacity.


   Less than 3 miles away from our fields are very rich glacial till soils that we had farmed for 7 
  years  during our B&B ornamental growing period. These soils have bottomless nutrition and superior water holding capacity, they never need to be fertilized and never need irrigation but they are useless for bare root plant production because they are a mucky mess during the wet winter months when we harvest. Across the temperate United States we have a matrix of soil types in diverse climatic zones and diverse geological origins that are equally different from soils and climates of the moist tropics where terra preta has been described. 



  Is is not premature to write down guidelines for 'using'  - Tom wrote - 'terra preta' , I would write charcoal in soil? 


  Where is the data that it works up here? Perhaps the Montana paper that described better nitrogen retention in forest soils where fire sources inorganic carbon is encouraging but for those of us who are trying charcoal out in soils in this venue what results and what evidence should convince us that - yes we are having a 'terra preta' effect in our farmed soils? Measuring the crop yields and looking for improvement in controlled studies with charcoal would be another useful indication but I have yet to see any conclusive evidence that shows crop yields, up here, are better when charcoal is applied. Yes some interesting indications that call for more studies but not any reason to stir up farmers and their technical support organizations to recommend the use if charcoal in soil much less to call it 'terra preta'.


  To me this is still an interesting research topic and is not ready for dissemination as proven agricultural methodology in the temperate zone


  Rich Haard, Propagation Manager, Fourth Corner Nurseries
  Bellingham, Washington






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