Development of Quick Test Method for Soil pH, Nitrate, Phosphorus, and Potassium Combining Chemicals and Phone Cellular Application

Conventional soil analyses are time-consuming; therefore, the quick test (QT) method is needed. This study was to assess accuracy of pH, N-nitrate, available phosphorus (P), and exchangeable potassium (K) analysis determined by QT developed Akvo calibrated with standard laboratory methods. The field research collected 131 samples, from horticultural lands in 4 regencies within East Java-Indonesia, started February August 2017. Soil measured were P, K, textures, organic C, CEC. colorimetric-based performed on sample extracted Mehlich 1, color dipping strip paper supporting chemical solutions. A smartphone camera used for reading, results directly displayed screen. method’s calibration models created stepwise multiple linear regression involving correlated properties. values (i.e. P) showed significant correlations laboratory. However, suggested that could be nitrate due having a relatively high correlation