Irrigation Technology, Maize Productivity and Resource-Use Trade-offs in Tanzania: Implications for Sustainable Intensification

Abstract

This study explored how different irrigation methods affect maize productivity and resource use on Tanzanian farms, using recent survey data from over 200 holdings. It examined basic trends, nitrogen use efficiency, and influential yield factors, ensuring robust analysis through extensive reliability checks. Results showed that flooding/furrow irrigation achieved the highest average yields (3.01 t/ha), while large-scale pivot systems accounted for 94.2% of total maize harvested. Although flooding/furrow systems used the most nitrogen-fertiliser (124.54 kg N/ha), they were less efficient in converting fertilizer to grain (26.09 kg grain kg⁻¹ N). Both flooding/furrow and pivot irrigation, as well as insecticide use, were linked to higher yields, whereas expanding maize area was associated with lower yield per hectare. These findings highlight the need to evaluate irrigation not just by total output but also by land and input efficiency, suggesting that sustainable intensification should focus on context-specific irrigation and better nitrogen management. However, because the data was based on observational records based on farmer reports, the study cannot draw firm conclusions about cause and effect or fully measure environmental efficiency.