Benefit, cost, and phosphorus use efficiency of mycorrhizal field-grown garlic at different soil phosphorus levels

A field experiment was conducted to determine the effects of arbuscular mycorrhizal fungi (AMF) and soil phosphorus (P) on bulb yield, benefit and cost analysis, and P use efficiency in garlic (Allium sativum L.). Treatments included application of the AMF Glomus mosseae inoculum to the planting furrows after treatment with different levels of P (0, 20, 40, and 60 kg P ha(-1)). Garlic cloves were planted in furrows within a day after treatments were imposed. AMF-inoculated plants had higher fresh bulb yields than plants in uninoculated plots regardless of P level. The enhancement in fresh bulb yield due to AMF-inoculation was highest in plots fertilized with 20 kg ha(-1). The AMF-inoculated plants had less P use efficiency than uninoculated plants. Bulb yield differences between AMF-inoculated and uninoculated plants were considered the benefit derived by plants from AMF-root associations. Bulb yield differences between AMF-inoculated and uninoculated plants with similar P concentrations were considered the costs paid by plants for AMF-root associations. Values of benefit and cost analysis for AMF-root associations were highest when soil P was lowest and decreased with increasing P application. Benefit and cost analysis may be helpful in evaluating host plants to optimize efficiencies of AMF symbiosis under field conditions.