Effect of Soil Properties on Coffee Quality in Ethiopia (Wollega University)
Published 08/11/2010
- 12:57 p.m. GMT
Influence of Soil Properties on Cup Quality of Wild Arabica Coffee in Coffee Forest Ecosystem of SW Ethiopia
By Abebe Yadessa Researcher and lecturer
Summary of the research
findings
A study to establish a relationship between cup quality of coffee and
soil properties was conducted in the coffee forest ecosystem of south western Ethiopia, the
home of wild arabica coffee. Cup quality of coffee depends on different factors
such as the type of coffee,
soil conditions, climatic conditions, processing methods etc. The
present paper assessed the influence of soil conditions of the Afromontane
rainforests in SW Ethiopia on cup quality of
wild arabica coffee. The study was based on 74 sample plots collected from
Sheko (40 samples) and Yayu (34 samples) forests. From each plot, red cherries
were hand picked and dry processed, and soil samples (0-20 cm depth) were also
collected. Soil texture, cation exchange capacity (CEC),
pH, major-nutrients and micro-nutrients were analyzed following the standard
procedures. The sensorial analysis was made in Ethiopia
by 5 professional tasters (3 from Ethiopia
and 2 from Germany).
Results showed that the overall cup quality of wild arabica coffee was not
correlated with total N and available P levels of the soil at Sheko, but
significantly and inversely correlated with N: P ratio. At Yayu, however, it
was neither correlated with N or P and nor with N: P ratio, but rather
significantly correlated with K, Ca, CEC
and pH values. The effect of micronutrients on coffee quality was more of
site-specific. Soil Zn content was negatively correlated with cup quality at
Sheko, but positively correlated at Yayu; that is, higher Zn concentration was
associated with poor coffee quality at Sheko but with better quality at Yayu.
Although the influence of soil properties varied according to the criteria and
from site to site, generally coffees with better cup quality were those
collected from plots with higher levels of available P, K, clay and silt, but
inversely correlated with sand content. Higher levels of soil pH, Mg, Mn and Zn
were also associated with improved coffee aroma. This indicates that the
quality of the soil is a very important factor for the production of quality
coffee, and specifically the balance between the different nutrients is of
paramount importance for the cup quality of coffee.
