Prairie soil improves wheat establishment and accelerates the developmental transition to flowering compared to agricultural soils.

Less than 1% of native prairie lands remain in the United States. Located in eastern Washington, the rare habitat called Palouse prairie was largely converted to wheat monocropping. With this conversion came numerous physical, chemical, and biological changes to the soil that may ultimately contribute to reduced wheat yields. Here, we explored how wheat (Tritcum aestivum L.) seedling establishment, plant size, and heading, signifying the developmental transition to flowering, were affected by being planted in prairie soil versus agricultural soils. We then sought to understand whether the observed effects were the result of changes to the soil microbiota due to agricultural intensification. We found that prairie soil enhanced both the probability of wheat seedling survival and heading compared to agricultural soil; however, wheat growth was largely unaffected by soil source. We did not detect effects on wheat developmental transitions or phenotype when inoculated with prairie microbes compared with agricultural microbes, but we did observe general antagonistic effects of microbes on plant size, regardless of soil source. This work indicates that agricultural intensification has affected soils in a way that changes early seedling establishment and the timing of heading for wheat, but these effects may not be caused by microbes, and instead may be caused by soil nutrient conditions.