Effect of Cofee Residue and Cropping System on Crop Yield and Physicochemical Properties of the Soil in Southern Ethiopia
Dumping and burning of coffee residue brought a serious environmental problem. On the other hand, low soil fertility due to multiple cropping with low input coupled with moisture stress results in decline in production. This study was conducted to evaluate decomposition and mineralization of N fr...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2005
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6165/1/FP_2005_5.pdf |
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| Summary: | Dumping and burning of coffee residue brought a serious environmental problem. On
the other hand, low soil fertility due to multiple cropping with low input coupled with
moisture stress results in decline in production. This study was conducted to evaluate
decomposition and mineralization of N from coffee residue, and its effect on soil
physicochemical properties, crop yield, and apparent nutrient balance. Decomposition
and release of N in soil was studied using five periods of incubation (0, 30, 60, 90, and
120 days) and four rates of residue (0, 3, 6, and 9 Mg ha-') in pot experiment. The same
rates of residue and four rates of N fertilizer (0, 30, 60, and 90 kg ha-'), urea as source,
were studied under field condition.
In the pot experiment, coffee residue decomposed in two phases: viz. an initial faster
phase, and a later slow rate of decay. Decomposition rate (KD) was controlled by lignin
(L) and nitrogen (N) contents, and L/N ratio ( R =~ 0.975**, n = 36). Immobilization of
soil N persisted for the entire 120 days, and release of N was controlled by lignin and
cellulose contents, residue N and L/N ratio ( R=~ 0 .982**).
In the field, coffee residue alone significantly increased the mean uptake of N (106%), P
(165%), and K (93%) in both maize and haricot bean, and its combination with N
fertilizer enhanced the uptake by 143, 172 and 102%, respectively, compared to the
control (without both residue and N fertilizer). Water use efficiency (WUE) increased
significantly by 78% for maize and land equivalent ratio (LER) by 7% using coffee
residue alone; and by 95% for total WUE and 16% for LER using residue along with N
fertilizer. Efficiency of intercrop was 13% higher than sole cropping. Grain yield of
maize with residue only varied between 52 and 88% of the sole maize yield (4,330 kg ha-').
In both pot and field experiments, soil amended with coffee residue showed increase in
moisture content, total N (TN) and OC content. In the field study, the residue increased
the physicochemical properties of the soil such as moisture (38%), TN (7.6%), and OC
(8%) compared to the control. Intercropping increased soil moisture (3%), available P
(8%) and K (15%) but reduced soil N (19%) and OC (4%) relative to the contents in sole
maize.
Depletion of 20 and 70 kg N ha-' was obtained in soil treated with coffee residue and N
fertilizer alone, respectively. On the other hand, a positive balance of 19.4 kg N ha-' was
obtained from application of coffee residue followed by N fertilizer. The loss of K was
high at 289 kg ha-' with coffee residue only and at 159 kg h i ' from coffee residue
followed by N fertilizer. Application of 9 Mg ha-' coffee residue and 9 Mg ha-' coffee
residue with 90 kg N ha-' gave the highest maize grain yields (3,807 and 4,133 kg ha-',
respectively) and monetary values of 1,834 and 2,367 birr ha-' (lUSD= 8.40 Ethiopian
birr), respectively, indicating the economic using coffee residues.
Amelioration of soil with coffee residue and/or N fertilizer provided improvement in soil
physicochemical properties and crop yields. Therefore, utilization of coffee residue
would not only provide an alternative source of plant nutrients but also alleviates soil
fertility and reduce environmental pollution problems. |
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