Empirical Investigation of the Role of Mycorrhizal Inoculation in Improving Phosphorus Uptake and Growth of Tomato in Phosphorus-Deficient Soils of Nasarawa State

Arbuscular mycorrhizal fungi form symbiotic associations with plant roots and can significantly enhance phosphorus acquisition from low-phosphorus soils, and their application as a biofertiliser in tomato production offers a potential complement to mineral phosphorus fertiliser in the P-deficient ferralsols of Nasarawa State. This study empirically investigated the effect of mycorrhizal inoculation at three phosphorus supply levels (0, 30, and 60 kg P2O5 ha-1) on phosphorus uptake, growth, and yield of tomato at Lafia LGA, Nasarawa State, North Central Nigeria. A 2x3 factorial (inoculated and uninoculated at three P rates) randomised complete block design with three replications was conducted during the 2023 dry season under supplemental irrigation. Mycorrhizal colonisation rate, shoot phosphorus concentration, leaf area index, fruit number per plant, individual fruit weight, and total fresh fruit yield were measured. Results showed that mycorrhizal inoculation significantly increased root colonisation rate (from 8.3 to 67.4 percent), shoot phosphorus concentration, and fruit yield at all P supply levels. The largest yield benefit from inoculation was at 0 P (uninoculated: 8.7 t ha-1 versus inoculated: 14.2 t ha-1). At 30 kg P2O5 ha-1, inoculation produced yield equivalent to the uninoculated 60 kg P2O5 ha-1 treatment (18.4 versus 18.1 t ha-1). The study provides empirical evidence for mycorrhizal inoculation halving mineral phosphorus requirements in tomato and recommends inoculant production and application protocols for Nasarawa State market garden extensification programmes.

Keywords: mycorrhizal inoculation, phosphorus uptake, tomato, Nasarawa State, biofertiliser