Results from the fertilizer demonstration experiment with maize at Farm for the Future Tanzania in Iringa, in 2020

Abstract

In 2020, an experiment was run for the third consecutive season at the Farm for the Future Tanzania Ltd. (FFF), which is part of Ilula Orphan Program’s (IOP) Farm, Ilula, Iringa Region, in Tanzania. The FFF farm is training farmers in 16 villages with a focus on dissemination activities at regional and national levels. The purpose of the experiment is to test and demonstrate crop fertilization strategies that combine high maize yields with high nutrient use efficiency (NUE) and low greenhouse gas (GHG) emissions. Five nutrient management treatments were combined in a full factorial setup with two tillage options. Highest yields were obtained with reduced tillage combined with NPK fertilizer to target 70% of waterlimited yield (Yw) and micro-nutrients (Mg, S, Zn combined), and with half NPK fertilizer and half composted manure. The lowest maize yields were obtained from both the treatment without fertilizer application and the fertilizer treatment with only P and K applied at reduced and conventional tillage. Results showed no significant differences in both agronomic N use efficiency (N-AE, additional grain yield per kg N applied when correcting for the P and K applied) and fertilizer use efficiency (additional grain yield per kg N applied when including yield effects from P and K) between reduced and conventional tillage. N-AE obtained in the experiment of 34.0 kg yield/kg N was much higher compared to the current average N-AE in sub-Saharan Africa of 14.3 kg yield/kg N. When targeting 70% of Yw for maize, this improved N-AE value could result in 58% reduction in GHG emission per hectare (ha) from fertilizer application (direct and indirect emissions). Despite the cancellation of the farmers field days, due to the Covid19 pandemic, ten young farmers still took part in the experimental setup and trial planting.