[Terrapreta] Charcoal and Other Carbon and Nutrient Sources

[Tom Miles]

The composting discussion raises the question of whether we should think more broadly about how combinations of biochar plus other techniques could work best to improve soil fertility depending on the circumstances. 

 

I note that Joseph Kimetu has been comparing the use of biochar with organic nutrient and carbon sources like Tithonia diversifolia in tropical Africa.   He gave a seminar last week at Cornell on: Restoration of soil organic matter in smallholder farming systems of Western Kenya. 

 

See:

 

http://a-c-s.confex.com/a-c-s/2007am/techprogram/P34909.HTM


Tuesday, November 6, 2007


Reversal of Productivity Decline in Agroecosystems with Organic Amendments of Different Stability.


Joseph Kimetu1, Johannes Lehmann1, Janice Thies1, Alice Pell2, Daniel N. Mugendi3, Andre Bationo4, and James M. Kinyangi1. (1) Crop and Soil Sciences, Cornell University, 1022 Bradfield, Ithaca, NY 14850, (2) Animal Science, Cornell University, Ithaca, NY 14853, (3) School of Environmental Studies and Human Sciences, Kenyatta University, P.O Box 43844-00100, Nairobi, Kenya, (4) African Network for Soil Biology and Fertility (AfNet), Tropical Soil Biology and Fertility Institute of CIAT, P.O Box 30677-00100, Nairobi, Kenya

 

In tropical agroecosystems, productivity declines associated with soil organic matter (SOM) degradation can be reversed through the application of organic inputs of diverse quality which also increase crop fertilizer use efficiency. To soils that had been under continuous cultivation for 4, 10, 30, and 100 years, four organic matter sources; Tithonia diversifolia, Hemsley A. Gray, cattle manure, wood charcoal and fine sawdust were incorporated at the rate of 6 tons C ha-1, for 3 seasons over a 2-year period. Full fertilizer N, P and K rates (120, 100, 100 kg ha-1 respectively) were superimposed to the organic treatment plots. For soil with a long-term 100-year cultivation history, the addition of N, P and K yielded a maximum of 3.0 t ha-1 of maize grain which more than doubled with the addition of Tithonia (6.7t ha-1 and 8.0t ha-1 in the first and second year respectively). For Tithonia, an increase of 2.0 ± 0.6 t ha-1 above the fertilized, no biomass treatment was observed in soil with medium cultivation history (20 yrs). In both years, application of manure increased maize grain yield by a similar 2.0 ± 0.3 t ha-1. No immediate changes to maize yield were noted with application of highly recalcitrant OM (charcoal and saw dust) but in the second year charcoal and sawdust addition yielded 2.9 t ha-1 and 1.7 t ha-1 respectively higher than control. Nutrient uptake by maize crop was significantly improved with the application of Tithonia and charcoal OM. Almost 30% increase in base saturation (%) of the soil was observed with the application of manure. Soil pH, potential CEC and effective CEC were also improved with the use of OM inputs. We show that improved SOM, especially in degraded soil, are an integral part of reversing soil productivity declines in tropical agroecosystems.

 

Kimetu, J.,  J. Lehmann, A. Pell and J. Thies. 2007. Carbon sequestration and mitigation of carbon accumulation in <http://ciifad.cornell.edu/activities/initiatives/biocomplexity/kimetu/kimetu0407iaipster.pdf>  the biosphere: the role of biochar in tropical agricultural systems. 2007 International AgriChar Initiative Conference. Terrigal, New South Wales, Australia. April 29-May 2, 2007.

 

Advances in Integrated Soil Fertility Management in sub-Saharan Africa Challenges and Opportunities 

Edited by A Bationo, B Waswa, J Kihara and J Kimetu 1000 pages  <http://www.nhbs.com/browse.php?pub=206> Springer-Verlag

 

Soil organic carbon dynamics, functions and management in West African agro-ecosystems. 

http://dx.doi.org/10.1016/j.agsy.2005.08.011

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: /attachments/20080401/aa0a239b/attachment-0001.html