Estimates of variation for measurements of selected soil parameters on slash-and-burn fields in Northern Laos
1995
Roder, W. | Phengchanh, S. | Soukhaphonh, H.
Monitoring changes in soil fertility is an important component in the evaluation of land-use systems. This research was undertaken to estimate short-range soil variability of selected soil parameters in slash-and-burn systems of Northern Laos as a prerequisite for planning long-term experiments. Coefficient of variation for the top interval (0-3 cm) was 10.4, 8.7, 20.7, 12.8, 75.8, and 44.8% for pH, total nitrogen (N), organic carbon (C), total phosphorus (P), available P, and available potassium (K), respectively (averaged over two sites). Variation generally decreased with increasing depth of soil interval, except for soil organic matter, where coefficient of variation was 14.1, 13.4, 14.6, 18.2, and 26.9% for intervals of 3-10, 10-25, 25-50, 50-75, and 75-100 cm, respectively. The number of sub-samples required to document changes in available P and K will be unrealistically high if high confidence levels are required. Correlation between pH and available P and K was high for the 0-3 cm interval.
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