Pear seedling responses to phosphorus,fumigation and mycorrhizal inoculation

The effects of P, fumigation and mycorrhizal inoculation on the growth and nutrient content of pear cv. Bartlett (Pyrus communis L.) seedlings were evaluated on the P-sorbing, Parkdale soil (Vitrandepts). The P treatment levels were 0.03, 0.04, 0.06, 0.09, 0.15, 0.25, and 0.40 mg P I-1 of soil solution, based on a P-sorption isotherm. At age 145 d, dry weight, plant height, and stem diameter responses to P and to biological treatments were highly significant as were all interactions. At P levels between 0.03 and 0.25 mg I'1 the greatest growth was observed in either the unfumigated control seedlings or those given the Glomus intraradices Schenck and Smith treatment. At the highest P level thegreatest growth was observed in the plants treated with Glomus deserticola Trappe, Bloss & Menge. At the highest P level, mycorrhizal colonization and concentration of Zn and Cu declined in control plants, but not in inoculated plants.