Phosphorus dynamics in the rhizosphere of two wheat cultivars in a soil with high organic matter content

Soil organic matter (SOM) is a key of most nutrient cycling and its content influences labile phosphorus (P) pool. In order to promote P availability from SOM, some plant strategies could be important to increase organic P mineralization, which may change among cultivars of the same crop. This study evaluated phosphorus dynamics in the rhizosphere of two wheat cultivars in soil with high organic matter content. Experiment was established in a greenhouse using a Humic Cambisol in a randomized block design using Quartzo and Abalone as wheat cultivars and harvested 20 days after seedling. Pots with a horizontal mesh (25 µm) were used to isolate the soil from roots. At harvest, the soil under the mesh was sliced in five distances from the rhizoplane (0–3; 3–6; 6–10; 10–20; 20–30 mm). Organic P was the buffer to maintain P dynamics in the rhizosphere and there was phosphorus depletion in the first slice near the rhizoplane due to the root effect, regardless the cultivar. Quartzo showed high labile inorganic P, presumably due to the high amount of root hairs, which increased the acid phosphatase activity and consequently root P uptake. Quartzo was more efficient in changing rhizosphere regarding the P acquisition.