Browsing by Author "Ledin, Stig"

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    Comparison Of Four Low-Technology Composting Methods For Market Crop Wastes
    (Waste Management,, 2009) Tumuhairwe, John Baptist; Tenywa, John Stephen; Otabbong, Erasmus; Ledin, Stig
    Four methods for composting, pit-cover (PC), pit-open (PO), above ground-open (AO) and above ground-covered (AC), were compared for their effect in accelerating compost maturity using market crop waste (MCW). The composting process was monitored through determining changes in temperature and pH, with compost maturity indices measured in terms of variations in water-soluble carbon (WSC), ammonium-N () and nitrate-N (), and C/N, , WSC/organic N and WSC/total N (TN). Total organic carbon (TOC), nitrogen (TN), potassium (TK) and phosphorus (TP) were also determined. Temperature rapidly increased from mesophilic to thermophilic and gradually reduced through maturation phases. A similar pattern was recorded for pH, which reached a slightly alkaline level at maturity. Composting significantly (p < 0.05) decreased the concentrations of TOC, TN, TP, TK, and WSC and increased that of . All four low-technology composting methods used in this study produced mature composts within 63 days. Suitable maturity indicators for MCW compost were C/N ratio < 12, WSC < 1%, < 400 mg kg−1, / < 0.2, WSC/TN, WSC/organic-N < 1. On the basis of these indicators, the AC method generally enhanced maturity faster than the AO, PC and PO methods. Pit methods require less investment and are recommended for the smallhold farmers.
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    Effectiveness of crop-waste compost on a Eutric Ferralsol
    (Journal of Plant Nutrition and Soil Science, 2011) Amoding, Alice; Tenywa, John Stephen; Ledin, Stig; Otabbong, Erasmus
    Lack of environmentally safe handling of garbage is a growing problem in urban sub-Saharan Africa (SSA). Composting the garbage for soil-fertility management presents an opportunity for reducing the risks of environmental pollution. This study aimed at evaluating the agronomic effectiveness and nutrient-utilization efficiency of urban market crop-waste compost on a Eutric Ferralsol. The study was conducted in central Uganda with treatments including compost applied at 0, 5, and 10 t ha–1 (d.w. basis); inorganic N fertilizer at rates of 0, 40, and 80 kg ha–1 and inorganic P fertilizer at 0, 9, and 18 kg ha–1. Maize (Zea mays L.), variety Longe 4 was used as the test crop. The nutrient quality of the compost was medium with total N of 0.9% and total P of 0.45%. Compost significantly increased plant height, LAI, stover weight, and grain yield; however, there were no significant differences between the 5 and 10 t ha–1 rates. Nitrogen also had a significant effect on LAI and stover yield, though there was no significant difference between the 40 and 80 kg ha–1 rates. Likewise, P increased plant height with no significant difference between the 9 and 18 kg ha–1 rates. Mineral N at 40 kg ha–1 led to the highest increase in N uptake by plants (76%) above the control. Nitrogen- and P-utilization efficiencies for the 5 t ha–1 compost rate were more than twice that of the 10 t ha–1 rate. The highest P-utilization efficiency (69%) was obtained where 9 kg ha–1 P was applied with 40 kg ha–1 N, while the highest N-utilization efficiency (48%) was obtained with the 5 t ha–1 compost applied together with N at 40 kg ha–1. From the above studies, it is clear that effectiveness of the 5 t ha–1 compost rate is the most promising.