Abstracts |
The effects of inoculating arbuscular mycorrhizal (AM) fungi on the growth, phosphorus (P) uptake, and yield of Welsh onion (Allium fistulosum L.) were examined under the non-sterile field condition. Welsh onion was inoculated with the AM fungus, Glomus R-10, and grown in a glasshouse for 58 days. Non-inoculated plants were grown as control. Inoculated and non-inoculated seedlings were transplanted to a field with four available soil P levels (300, 600, 1,000, and 1,500 mg P2O5 kg -1 soil) and grown for 109 days. AM fungus colonization, shoot P concentration, shoot dry weight, shoot length, and leaf sheath diameter were measured. Percentage AM fungus colonization of inoculated plants was 94% at transplant and ranged from 60% to 77% at harvest. Meanwhile, non-inoculated plants were colonized by indigenous AM fungi. Shoot length and leaf sheath diameter of inoculated plants were larger than those of non-inoculated plants grown in soil containing 300 and 600 mg P2O5 kg -1 soil. Shoot P content of inoculated plants was higher than that of non-inoculated plants grown in soil containing 300 and 600 mg P2O5 kg-1 soil. Yield (shoot dry weight) was higher for non-inoculated plants grown in soil containing 1,000 and 1,500 mg P 2O5 kg-1 soil than for those grown in soil containing 300 and 600 mg P 2O5 kg-1 soil. Meanwhile, the yields of inoculated plants (200 g plant -1) grown in soils containing the four P levels were not significantly different. Yield of inoculated plants grown in soil containing 300 mg P2O5 kg -1 soil was similar to that of non-inoculated plants grown in soil containing 1,000 mg P 2O5 kg -1 soil. The cost of AM fungal inoculum for inoculated plants was US$ 2,285 ha -1 and lower than the cost of superphosphate (US$ 5,659 ha -1) added to soil containing 1,000 mg P2O5 kg -1 soil for non-inoculated plants. These results indicate that the inoculation of AM fungi can achieve marketable yield of A. fistulosum under the field condition with reduced application of P fertilizer. |