本研究目的擬針對甘比亞地區土壤特性，探討施用化學肥料對水稻生長、產量及土壤肥力之影響，以期建立適當且合理的化學肥料應用技術。試驗處理包括複合肥料 (N-P₂O₅-K₂O=15-15-15%) 及尿素 (N 46%) 等不同用量組合，共計八級處理，分別在 Sapu 潮汐灌溉區、 Jahally 抽水灌溉區及 Sukuda 看天田等試區進行田間試驗。由試驗結果顯示，在 Sapu 潮汐灌溉試區， 1999 年秋作水稻產量以 A 處理 ( 複合肥料 200 kg/ha ，尿素 200 kg/ha) 的 6.85 t/ha 較高，其次為 D 處理 ( 複合肥料 100 kg/ha ，尿素 200 kg/ha) 的 6.61 t/ha 。 2000 年春作水稻產量則以 D 處理的 6.41 t/ha 較高。在 Jahally 抽水灌溉試區，水稻產量以 D 處理的 5.78 t/ha 較高。在 Sukuda 看天田試區，水稻產量以 E 處理 ( 複合肥料 100 kg/ha ，尿素 100 kg/ha) 的 5.06 t/ha 較高。顯示在水源充足地區，如潮汐灌溉及抽水灌溉區，在使用複合肥料 100 kg/ha 及尿素 200 kg/ha 的 D 處理 (N-P₂O₅-K₂O=107-15-15 kg/ha) 時，可獲得相對較高的水稻產量。在水源較不足如看天田地區，則在使用複合肥料 100 kg/ha 及尿素 100 kg/ha 的 E 處理 (N-P₂O₅-K₂O=84-15-15 kg/ha) 時，即可獲得較理想的水稻產量。

關鍵字： 化學肥料、水稻、土壤肥力、甘比亞。

The purpose of this research is to evaluate the effect of chemical fertilization on yield enhancement of rice and soil fertility in the Gambia. There were eight treatments conducted with different application amounts of compound fertilizer (N-P₂O₅-K₂O= 15-15-15%) and urea (N 46%). Field experiments were conducted at sapu (tidal irrigation), Jahally (pump irrigation) and Sukuda (rain- fed) in the Gambia. The results indicated that the highest of rice yield (6.85 t/ha) was found on the treatment A (compound fertilizer 200 kg/ha; urea 200 kg/ha) at sapu in 1999 fall. The second was showed on the treatment D (compound fertilizer 200 kg/ha; urea 100 kg/ha) that the rice yield was 6.61 t/ha. However, there was not significantly different between the treatment A and D. In 2000 spring, the highest of rice yield (6.41 t/ha) was found on the treatment D at sapu. The rice yield of treatment D that was 5.78 t/ha was the best treatment than other treatments at Jahally in 1999 fall. The rice yield of treatment E (compound fertilizer 100 kg/ha; urea 100 kg/ha) that was 5.06 t/ha was the best treatment than other treatments at Sukuda in 1999 fall. Therefore, the reasonable fertilization for rice was treatment D (compound fertilizer 200 kg/ha; urea 100 kg/ha) at sapu and jahally that used by tidal and pump irrigation. For rain- fed rice such as at Sukuda, the reasonable fertilization was treatment E (compound fertilizer 100 kg/ha; urea 100 kg/ha).

Key words: chemical fertilization, rice, soil fertility, the Gambia.