Handheld NDVI sensor-based rice productivity assessment under combinations of fertilizer soil amendment and irrigation water management in lower Moshi irrigation scheme, North Tanzania

Abstract Handheld optical sensor was used to measure canopy reflectance at red region (656 nm) and near-infrared (774 generate NDVI data for monitoring rice productivity under soil amendment with combinations of fertilizers two levels water regime in smallholder Irrigation Scheme, Lower Moshi, North Tanzania. The study carried out an experimental design which consisted irrigation (flooding system intensification) multi-nutrients (NPK) single nutrient (urea) application replicated three times a randomized complete block design. Flood applied 7 cm height throughout the growing season, while SRI treatment 4 alternate wetting drying conditions. annual rates 120 kg N/ha, 20 P/ha, 25 K/ha. variety SARO-5 this experiment. Simple correlation coefficient ( r ) degree association between field crop performance parameters (plant height, number tillers, biomass, yield) across growth stages positions above tested fertilizer regimes. Results show that any given fertiliser levels, there no significant plant except vegetative stage 0.6 m booting 0.3 canopy, respectively P < 0.05). A good also observed full regardless position tillers relationship grain yield vegetative, booting, stage. simple linear regression models explained only slightly 30% predictions by early growth, decreasing gradually 5% demonstrate positive amendments Thus, we conclude handheld NDVI-based can be optimising use management. This allows future multi-functional land management within soil–water-food nexus.