Physicochemical Characterization of Nitisol in Southwestern Ethiopia and Its Fertilizer Recommendation Using NuMaSS

Abstract

Nutrient management decision support system (NuMaSS) is a tool that diagnoses soil constraints
and selects the appropriate management practices, based on agronomic, economic and
environmental criteria, for location-specific conditions. However, its validation in different soil
types and agroecology should be tested. Thus, the present study was conducted to assess the
fertility status of Nitisol and suggests the application of NuMaSS as a diagnostic tool to
recommend supplementary N and P fertilizers for maize across different agroecology zones.
Accordingly, fifty soil samples were collected from five locations and analyzed for the major soil
physical and chemical properties. The soil pH-H2O was below the critical level for all soil samples.
Nitrogen, Cu and Zn were deficit in all soil samples. Deficiency of available phosphorous was also
observed in 88% of the soil samples. High probabilities of nitrogen and phosphorous deficiency
were also observed in the study areas using NuMaSS. Moreover, 24 Kg/ha P and 73 Kg/ha N for
Dedo; 24Kg/ha P and 82 Kg/ha N for Agaro; 20 Kg/ha P and 100 Kg/ha N for Serbo; 27 Kg/ha P and
94 Kg/ha N for Dimtu; and 4.9Kg/ha P and 97 Kg/ha N for Asendabo were recommended for maize
using NuMaSS.