Agrica

In buckwheat field the rhizosphere tartaric acid (μg g^-1) and soil phosphorus availability (μg, g dry soil^-1) concentration was higher in no added FYM plot (0.51 and 15.3) than added FYM plot (0.27 and 13.94), respectively which proved that buckwheat as a cover crop enhanced rhizosphere soil phosphorus in acidic soil. Such findings also suggested that organic-anion root exudation have a role in buckwheat-rhizosphere P- dynamics. As a cover crop, buckwheat (Fagopyrum esculentum) may increase soil-P availability. Buckwheat was grown in low-phosphorus and phosphorus-Farm Yard Manure (FYM) field plots, and organic anions were measured in rhizosphere soil. Soil-P availability was not affected by buckwheat, but the concentration of rhizosphere tartrate^2- was significantly higher (p < 0.005) in low-P vs. P-FYM plots. This suggests that organic- anion root exudation may have a role in buckwheat- rhizosphere P dynamics. The increase in soil pH ranged from 0.05 to 0.13 units along with soil organic carbon from 0.07% to 0.25% was also observed. Soil available phosphorus (Bray P₁) decreased from initial 22.6 kg/ha to 16.80 kg/ha indicating P uptake capacity of buckwheat from soil. In another pot study results revealed that lack of difference in buckwheat biomass between all the treatments may be a compensatory mechanism to uptake greater P. In acid soil with high aluminium (Al⁺³) toxicity, P solubilization was accelerated by some of the organic anions like oxalate, tartrate which were exudated by buckwheat roots. These oxalate and tartrate anion interacted with different phosphate complexes to increase the P in soil solution which suggested that direct rhizosphere chemical alteration played greater role to enhance P uptake.