Variability and critical values of nutrients in a highland banana farming system in East Africa
JoanPaula Elliseus Rutazaha1, Jacob Kaingo2, Peter Wilson Mtakwa3, Godfrey Taulya4
1International Institute of Tropical Agriculture (IITA), Tanzania
Poor soil fertility remains a major constraint in East African highland banana systems. Site-specific nutrient management practices promote attainment of sustainable yields. Critical values and their spatial distribution are an essential component for designing a sustainable nutrient management plan. This study was conducted to map the spatial distribution of nutrients and to determine the respective critical values for banana production in Rombo District, Tanzania. It involved a survey of 100 smallholder banana farms. Soil samples were collected at 0-30 cm depth along with plant samples. The samples were analysed for physicochemical properties and nutrient concentrations, respectively. Data on girth at base (Gbase) and at 1-m height from the ground (G1), number of hands per bunch and number of fingers on the bottom row of the second-last hand were collected from three selected mats per farm for allometric estimation of fresh bunch weights. Aboveground biomass (AGB) for the mother plants was also determined. Boundary line analysis was used to determine critical values. Matoke had a significantly (P≤0.05) higher Gbase, G1 and AGB than Malindi and Mshare, whereas Malindi had significantly (P≤0.05) more hands. Kriging was used to generate the nutrient distribution maps. There was no significant difference (P≤ 0.05) among the cultivars for fingers and bunch weight. Critical values in banana leaves were 2.39, 0.15, 1.5, 0.35 and 0.3% for N, P, K, Ca, and Mg, respectively. Coefficient of variation was observed was in the order P>Cu>K>Zn>Mn>S. Results provide a basis for nutrient management practices and fertiliser recommendations for enhancement of yields in banana farming systems.
Keywords: Banana farming systems, critical values, kriging, soil fertility
Contact Address: Jacob Kaingo, Sokoine University of Agriculture, FoCoActive Project, P.O. Box 3006, Morogoro, Tanzania, e-mail: jacobkaingogmail.com