Assessment of Endogenous Soil Fertility to Update Fertilization of Maize (Zea mays L) Crops in the Savannah Region of Togo

Abstract

The diagnosis of soil fertility is a prerequisite for the formulation of balanced and site-specific fertilizer recommendations. Macro elements (nitrogen – N, phosphorous – P and potassium – K) based nutrient omission trials were conducted in the districts of Oti, Tandjoare, Tone and Kpendjal of the Savannah region. The objective was to assess endogenous soil fertility under maize cropping to further develop updated site-specifique fertilization schemes for the crop. A total of twenty-five producers were selected in the region (eight in Tandjoare, seven in Tone, five in Oti and five in Kpendjal) for the study in a paticipatory approach. The approach was participatory in order to involve the end user in the exercise. A randomized complete block design was adopted with five fertilization treatments including N0P0K0 (T1), N0P60K70 (T2), N120P0K70 (T3), N120P60K0 (T4) and N120P60K70 (T5) kg ha-1 for the trial. The unit plot size was 100 m2 (10 m x10 m). Grain yield, yield response to nutrients and Agronomic Efficiency (AE) were determined. Genstat Edition 12th was used to discriminate means.The average yields were 0.56, 0.83, 3.18, 3.44 and 4.57 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Tandjoare, 0.32, 0.52, 1.06, 2.39 and 3.02 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Tône, 1.01, 1.35, 2.56, 3.16 and 4.39 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Oti and 0.39, 0.75, 1.54, 2.33 and 3.31 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Kpendjal. The ranking of yield data by fertilizer treatment indicates that all three macronutrients (N, P and K) are required for maize production in the Savannah region, with a priority ranking of N>P>K. The results also showed that the best Agronomic Efficiency is obtained when all macronutrients are supplied in all four districts. The results of this diagnostic will be used as a basis for formulating balanced, site-specific fertilizer recommendations for intelligent, environmentally-friendly agriculture.