Soil moisture management and fertilizer micro-dosing on yield and land utilization efficiency of inter-cropping maize-pigeon-pea in sub humid Tanzania

•This study was conducted to investigate main and combined effects of inter-row rainwater harvesting, fertilizer micro-dosing and cropping systems on maize and pigeon-pea production.•Tied ridges conserve soil moisture 24% more than flat and improved maize yield by 0.3 tha−1; fertilizer application increased maize yield by 1.12 and 1.60 tha−1 than control.•Tied ridges conserved more soil moisture than flat cultivation, this enhanced fertilizer use efficiency that improved crop yield and land equivalent ratio under inter-cropping. Principally caused by soil water stress and declining soil fertility, low crop productivity results in both food and income insecurity. The effects of nitrogen and phosphorus fertilizer micro-dosing with inter-row rainwater harvesting practices for maize and pigeon-pea inter-cropping on yield and land use efficiency are inadequately documented in sub humid tropics. A field experiment on sandy loam soils in sub humid conditions using a split-split plot design was conducted. Plots used in situ rainwater harvesting practices of tied ridges, open ridges, and flat cultivation. Sub-plots were sole maize, sole pigeon-pea, and 1:1 maize-pigeon pea inter-cropping. The sub-sub plots were control, fertilizer (N and P) application at the micro-dose level, and recommended rates. Tied ridges significantly (p