Soil Analysis Examples and Coffee Nutrients
When buying soil for growing coffee, the
following values are recommended for coffee soil (Malavolta,
201):
P
(resin) - 15-30 µg/cm3.
P
(Mehlich 1): 10-20 ppm
SO4-S:
10-15 µg/cm3.
K%
CEC (pH 7.0): 10-15%
Ca%
CEC (pH 7.0): 40-60%
Mg%
CEC (pH 7.0): 10-15%
V%:
60-70%
CEC
(pH 7.0): 7-10 meq/100 cm3.
B
(hot water): 0.4-0.5 ppm.
B
(0.05 N HCl): 1.0-1.2 ppm.
Cu
(Mehlich 1): 2-3 ppm.
Zn
(Mehlich 1): 4-7.
Analysis of Soil: Correcting Problems
Lime is often used to help correct
acidic soils to a pH between 4.5-5.5 in the first 20 cm of
soil. When planting coffee, the holes should be covered with
250-500 g of limestone per meter (Mavolta, 199). Production
increases of up to 500% have been observed by adding limestone.
In Brazil the highest producing plantations had a pH from
6.0-6.5, a cation exchange capacity of 40-50%, and the base
saturation in the upper 20 cm was 60% (Malavolta, 198).
The requirement for lime can be calculated as follows:
Lime
needed = (T(V1-V2)/RPTN)p where
T
- meq/100 cm3 of exchangeable H+Al+K+Ca+Mg
V1=S/T*100
RPTN=Relative
Power of Total Nutrition. The average is 75%.
p=factor
of compensation for depth:
= 0.5 for 0-10 cm.
= 1.0 for 0-20 cm.
=1.5 for 0-30 cm.
(From
Malavolta, 198).
To correct
problems with acidity below 20 cm deep phosphogypsum is often
applied. Mavolta suggest that phosphogypsum should be
applied when aluminum saturation is higher than 20% or the
participation of Ca in the effective CEC is lower than 40% (Malavolta, 200).
Coffee Fertilizer
Since the coffee hullls and pulp are
rich in nutrients, many people often use coffee grounds as fertilizer.
One 60 kg bag of coffee contains 1,026 g of nitrogen, 60 g
of phosphorous, 918 g of potassium, 162 g of calcium, 90 g
of magnesium, 72 g of sulfur, 0.96 g of boron, 0.80 g of copper,
3.6 g of iron, 1.2 g of manganese, 0.002 g of molybdenum,
and 0.72 g of zinc (Malavolta,
197). The pulp resulting from processing contains
1,068 g of nitrogen, 84 g of phosphorous, 2,250 g of potassium,
246 g of calcium, 78 g of magnesium, 90 g of sulfur, 2.04
g of boron, 1.08 g of copper, 9.0 g of iron, 1.80 g of Manganese,
0.004 g of Molybdenum, and 4.20 g of Zinc (Malavolta 197).
Mineral deficiencies in mineral content
can usually be detected visually from looking at the coffee bean leaves.
See Coffee Bean Leaf Analysis for more
information on laboratory tests available.
Related
Articles
Mineral Deficiencies
Coffee Leaf Analysis
Growing Coffee
Environmental
Conditions for Growing Coffee
Coffee
Plant
Climate
CEC