Farmers are increasingly aware of the need for correct fertilizer management, and have developed a keen interest in the rapid and accurate assessment of soil nutrient status. A simple field‐based soil test for phosphorus (P), adapted from commonly used laboratory tests would allow the farmer to assess quickly fertilizer requirements. We have adapted themalachite green method forthe determination of P in water to a single‐solution technique for the determination of inorganic P in Olsen and Bray No. 1 extracts of soil. The method was modified for use in the field. The proposed method is at least four times as sensitive as the commonly‐used ascorbic acid method, simpler in application and the reagent is much more stable.