As a cover crop, buckwheat (Fagopyrum esculentum) may increase soil-P availability. Buckwheat was grown in low-P and P-fertilized field plots, and organic anions were measured in rhizosphere soil. Soil-P availability was not affected by buckwheat, but the concentration of rhizosphere tartrate2– was significantly higher (p < 0.005) in low-P vs. P-fertilized plots. This suggests that organic-anion root exudation may have a role in buckwheat-rhizosphere P dynamics.
Possinger, A.*, L.B. Byrne, N. Breen. 2013. "Effect of buckwheat (Fagopyrum esculentum) on soil phosphorus availability and organic acids." Journal of Plant Nutrition and Soil Science 176: 16-18.