Static Pile Compost System for Coffee Farms in Northern Thailand.

The rural farming community of Maejantai in northern Thailand needed an alternative soil supplement to synthetic fertilizer for their coffee farms in order to explore becoming certified organic coffee producing farms.  This study was conducted to investigate if a static pile system was an appropriate and effective composting method for the community of Maejantai. It also discerned which feedstock formula yielded the highest level of nutrients, highest percent organic matter, and lowest pathogenic organism count. Two static piles were constructed in March 2014 in the community: one with cow manure and rice straw layered in a 1:4 ratio and one with cow manure, rice straw, and coffee cherries layered in a 1:3:1 ratio. The piles were watered and monitored daily and after 8 weeks the finished compost piles were tested for nutrient and pathogenic organism levels. Both static piles produced a finished product that surpassed Thai composting standards. The compost pile with the coffee cherries yielded an overall higher quality product than the compost pile without coffee cherries. The quantity of nitrogen (N) and carbon (C), for the pile with coffee cherries was 2.08% and 23.47%, respectively; and for the pile without cherries was 1.38% N and 18.89% C.  Phosphorous and potassium concentrations for the pile with cherries was 2,816 mg/kg and 21,404 mg/kg, respectively; and for the pile without cherries was 2,561 mg P/kg and 11,560 mg K/kg. The percent organic matter was 34.88% and 20.93% for the pile with coffee cherries and the pile without coffee cherries, respectively. The pile with coffee cherries had 1,100 MPN fecal coliforms/g and < 3 MPN Escherichia coliforms/g. The pile without coffee cherries had 93 MPN fecal coliforms /g and < 3 MPN Escherichia coliforms/g.  The greater quantity of fecal coliforms found in the coffee cherry compost pile relative to the compost pile without coffee cherries was probably a result of the fact that the pile without coffee cherries spent five more weeks in the thermophilic decomposition stage than the pile with coffee cherries. Development of a static pile composting system was a successful and “low-tech” technique for generating high quality compost in the developing world.  Moreover, a static pile composting system with cow manure, rice straw, and coffee cherries produced a higher quality compost than piles without coffee cherries; thus, demonstrating a sustainable technique to recycle a typical waste product in the production of coffee beans.