NORMS FOR MULTIVARIATE DIAGNOSIS OF NUTRIENT IMBALANCE IN THE EAST AFRICAN HIGHLAND BANANAS (MUSA SPP. AAA)

Abstract

Despite low yields and soil fertility problems, fertilizer use in the East African Highland banana (AAA-EA) production is absent. High fertilizer costs increase the need for site-specific fertilizer recommendations that address deficiencies. This study aimed to derive and compare norms for AAA-EA bananas, using Compositional Nutrient Diagnosis (CND), Diagnosis and Recommendation Integrated System (DRIS), and a DRIS that includes a filling value (DRIS-R_d), and study nutrient interactions. Data on foliar nitrogen, phosphorus, potassium, calcium, and magnesium concentrations, and plant performance were obtained from 300 plots in Uganda. CND indices were closely related to DRIS and DRIS-Rd indices (R² > 0.965). Four nutrient interactions were common in both low and high bunch weight subpopulations. Although the three approaches can be used to determine nutrient imbalances in AAA-EA bananas, we recommend CND for ease of use. Diagnosis of nutrient deficiencies should be based on methods that identify plant nutritional imbalances.

Keywords:

• compositional nutrient diagnosis (CND)
• diagnosis and recommendation integrated system (DRIS)
• foliar nutrient concentration
• nutrient imbalance
• nutrient interactions

ACKNOWLEDGMENTS

The authors are grateful to the host farmers on whose plots the data was collected. We also thank Symon Wandiembe for suggestions and support with some statistical aspects of this paper, NARO for laboratory analysis of soil and foliar samples, and Godfrey Taulya for support with quality maintenance of laboratory results. The authors are also grateful to Professors M. Tenywa and M. Bekunda of Makerere University, Uganda, for supporting the first author's PhD research of which this paper is a component. This research was funded by USAID through Agricultural Productivity Enhancement Program (APEP).