Under filed conditions, mycorrhizal inoculum effectiveness depends on plant species and phosphorus nutrition

Abstract

The cultivation of horticultural crops, such as green peppers, tomatoes, eggplants and bell peppers is very common in semi-arid Mediterranean climate conditions. Two field experiments were performed to determine the effect of mycorrhizal species, plant species and phosphorus levels on mycorrhizal effectiveness and phosphorus (P) and zinc (Zn) nutrient uptake. In the first experiment, under field conditions, four plants species were inoculated with five arbuscular mycorrhizae (AM) species. In the second field experiment, under the same soil conditions, the same plant species were treated with three levels of phosphorus (P), i.e., control; 50 kg and 100 kg P₂O₅ ha⁻¹. The most effective mycorrhiza species Claroideoglomus etunicatum selected in the first experiment was used in the second field first experiment. In the first experiment, fruit yield enhancement, yield increase, inoculation effectiveness and nutrient concentration in the plant leaves were analyzed. Under field conditions, plant species growth is strongly dependent on the species of AM fungi. Tomato and green pepper plants were inoculated with Cl. etunicatum, eggplants were inoculated with Funneliformis mosseae and bell peppers were inoculated with Rhizophagus clarus, which are high fruit-yielding plant species. In general, Fu. mosseae and Cl. etunicatum increased the yield of the tomatoes, green peppers and eggplants. It seems mycorrhiza species specific to plant species. In the second experiment, mycorrhizal inoculation with P fertilizer application, in particular a moderate amount of P (50 kg ha⁻¹ P₂O₅) fertilizer increased the green pepper, bell pepper and tomato fruit yield compared with non-inoculated plants and non-P fertilizer application treatments. Increasing the application of P level reduced the mycorrhizal inoculation effectiveness (MIE). The results indicate that for all four solanaceae family plants 50 kg ha⁻¹ P₂O₅ is a P level threshold for mycorrhizal development, which enhanced plant growth and addition of fertilizer over 50 kg ha⁻¹ P₂O₅ reduced MIE. P and Zn uptake were significantly increased with mycorrhizal inoculation. These findings are supported by our hypothesis that mycorrhiza inoculation can reduce mycorrhizal dependent horticultural plants P fertilizer requirement.

Keywords:

• AM fungi species
• bell pepper
• tomato
• eggplant
• green pepper
• mycorrhizal inoculation effectiveness
• phosphorus uptake

Acknowledgments

The authors wish to thank the Çukurova University for financial support.