PRODUCTION OF CHAR FOR AGRICULTURE; A PROFILE OF BEST’S TECHNOLOGY

PRODUCTION OF CHAR FOR AGRICULTURE;A PROFILE OF BEST’S TECHNOLOGY
Biomass energy Services technology, Pty, Saratoga, NSW, Australia February 7, 2007

See attached article.

EXECUTIVE SUMMARY
Recent research work has shown that char in soil can have a range of benefits in the growth of plants. Char can also be used to improve the quality of potting mixes and to remediate soil. In this paper, details of the types of waste that can be converted to char are provided along with the chemical composition of the char. BEST’s Paddle Pyrolysis unit can be used to convert most waste to char, this process is detailed in this document.

INTRODUCTION
Organics can be recycled utilizing a composting process or through thermal conditioning to produce a char. This latter product has the advantage that it is dry, has a concentration of macro and micro nutrients and can be applied with standard fertilizer spreading equipment. Char can be produced at the site where waste is produced and processing is much faster compared to composting. BEST has been producing chars from various wastes and from wood since 1996. BEST has been able to enhance the performance of such chars with conventional inorganic fertilizers as well as sterile organic streams (such as green waste, chicken manure and dairy manure).
Recent research carried out both in Australia and overseas has shown that yields of crops can be significantly improved when the char and inorganic fertilizers are combined (shown in Figure 1). In 2003, Steiner, C. et al investigated the sorghum plant yields using different combinations of char, chemical fertilizer and organic material. They found that the yield of sorghum plant increased from 0.3 t/ha to 1.2 t/ha after adding char.

In 2002 Glaser et al reviewed the physical and chemical properties of char and found higher nutrient retention and nutrient availability after charcoal additions to soil, related to higher exchange capacity, surface area, and direct nutrient additions.

The benefits from addition of char in organic fertilizer can be listed as follows:
• It is an absorbent for soil-damaging herbicides and pesticides. The greater the degree of activation of high carbon ash the more absorbent it becomes.
• It absorbs and neutralises the natural toxins in decomposing organic materials, particularly those in bark and so on.
• It absorbs at least some of the harmful chloride and fluoride found in tap water.
• It removes the germination-inhibiting chemical from the seed surface.
• It decreases NH4 leaching and increases the nutrient-use efficiency.
• It helps retain soil moisture due to its high porosity.