| Abstract: | Cattle dung contributes to hot‐spot inputs of nutrients to grassland systems, but not much is known about its organic P (Po) composition and fate in the grassland soils. We used 31Phosphorus (P)–Nuclear Magnetic–Resonance (NMR) spectroscopy of alkaline soil extracts to examine potentials for tracing of different functional Po forms into a temperate grassland soil amended with dung. The proportion of monoester, DNA‐diester, and phospholipid+teichoic acid P were comparable in dung extracts, but the soil was dominated by monoester P. The temporal trends in the DNA‐diester P–to–monoester P (DDNAM) and diester P–to–monoester P (DM) ratio of dung, native soil, and soil amended with dung were monitored in the 70 d field experiment. The DDNAM and DM ratio in the dung‐amended soil (0–1 and 1–5 cm depth) were always intermediate between the dung and (unamended) control soil. Clearly, extracted soil P was a mixture of incorporated dung‐derived P and native soil P. The dung‐P contribution in the 0–1 cm samples peaked at 47% of the total extracted P at day 70 and at 15% after 42 d in the 1–5 cm soil depth (based on the DM ratio). The proportions of dung‐derived P and C in the soil were positively correlated with: 1) topsoil, using the DDNAM ratio (r2 = 0.975), and 2) top‐ and subsoil, using the DM ratio (r2 = 0.656). We concluded that our DDNAM and DM‐P ratios approach (obtained from solution‐31P NMR) did trace successfully the short‐term dynamics and fate of dung Po in soil. It indicated that dung‐derived Po varied as rapidly in soil as the dung‐derived C. |
