Beneficial microbes, plant extracts and cropping systems enhance maize yield and land use efficiency via rhizosphere microbial biomass nitrogen, acid phosphatase and urease activities

Maize production plays vital roles in food security and income of many farmers, but poor soil fertility poses significant challenge to yield, irrespective of the cropping system. This field study was setup as split plot in two alternate cropping seasons (September 2021 and April 2022) with mono- and inter-cropping systems as main plots, and seven treatments as sub-plots (Control, chemical–NPK + Lamida gold(Insecticide), Tithonia diversifolia –Ti + Piper guineense –Pi, Plant growth-promoting bacteria–PGPB + Endophytic fungi–EF, EF + Pi and PGPB + EF + Ti + Pi). The consortium of PGPB + EF + Ti + Pi significantly ( P < 0.001) enhanced maize yield by 41.4% in 2021 and 103.5% in 2022) when compared to the control which was statistically identical to NPK + Lamida gold across cropping systems. Maize + cowpea intercrop system enhanced land use efficiency by 58% and 88% during the September 2021 and April 2022 cropping seasons, respectively. PGPB + EF + Ti + Pi significantly ( P < 0.001) enhanced soil microbial biomass nitrogen, urease, and acid phosphatase activities, as compared to the chemical input and control at the R6 stage. Furthermore, maize yield correlated significantly ( P < 0.05) with soil microbial biomass nitrogen (r = 0.47), acid phosphatase (r = 0.49) and urease activities (r = 0.70 and r = 0.44) across the cropping systems and seasons. Intercropping significantly ( P < 0.001) increased soil acid phosphatase and microbial biomass nitrogen more than sole cropping. These results demonstrate potentials of beneficial microbes and plant extracts to enhance maize yield, and the importance of intercropping in maximising land use efficiency, thereby, highlighting their role in sustainable agriculture.