Inoculation with Arbuscular Mycorrhizal Fungi or Crop Rotation with Mycorrhizal Plants Improves the Growth of Maize in Limed Acid Sulfate Soil

Arbuscular mycorrhizal fungi (AMY) improve the uptake of immobile mineral nutrients such as phosphate, thereby improving plant growth. In acid sulfate soil (ASS), AMY spore density is generally low which impacts root colonization and phosphate uptake. Thus, inoculation may help increase AMY colonization of crops grown in ASS. AMY spore density decreases after cultivation of a non-host crop or bare fallow. In addition, preceding crops affect the growth and yield of subsequent crops. The production of AMY inocula requires AMY-compatible plants. The objective of the present study is to elucidate the effect of preceding crops on the persistence of inoculated AMY and growth of succeeding maize under an ASS condition with lime application. Spore density of AMY after cultivation of preceding crops (soybean or job's tears) was maintained in comparison to fallow leading to higher AMY colonization of maize and improved plant growth. Thus, maintenance of AMY spore density, either through selection of preceding crops or application of AMY inoculum, may be a viable strategy to improve maize growth in limed ASS of Thailand.