Comparative DRIS and Crop Log Diagnosis of Sugarcane Tissue Analyses1

Abstract

AbstractThe Crop Log system of sugarcane (Saccharum spp. hybrid) tissue analysis is a critical concentration approach which is widely used for the diagnosis of nutrient deficiencies and imbalances in the Hawaii sugar industry. Recent studies conducted elsewhere suggest that the Diagnosis and Recommendation Integrated System (DRIS), which utilizes ratios of tissue nutrient concentrations rather than the concentrations themselves, consistently gives a lower percentage of incorrect diagnoses of nutrient deficiencies and imbalances than critical concentration approaches. In these studies, it is often unclear whether the higher accuracy of the DRIS approach was due to inherent advantages of the DRIS approach or to local calibration of the system. The objective of this study was to compare the diagnostic accuracy of the conventional Crop Log approach, a locally calibrated Crop Log approach, and DRIS. In an analysis of 28 past fertilizer experiments on the island of Hawaii the locally calibrated Crop Log and DRIS approaches gave 3 and 5% fewer incorrect diagnoses, respectively, than the conventional Crop Log approach. The results suggest that the DRIS approach can provide slightly more accurate diagnoses of nutrient deficiencies than the conventional Crop Log approach.