Soil Science & Plant Nutrition · 2013 · 19 citations · 10 references
AgricultureEarth SciencesSoil SciencesSoil ChemistrySoil FertilitySoil ScienceManure Nutrient ManagementNutrient MineralizationPhosphate MineralsPhosphorus CyclePhosphorus ManagementSoil Phosphorus ChemistryAvailable Soil PhosphorusInorganic Phosphorus CompoundsOrganic Phosphorus CompoundsPhosphorus Dynamics In ManurePhosphorus SolubilizationSequential ExtractionSoil Solution PhosphorusX-ray Diffraction Analysis
Abstract Swine manure compost (SMC) contains a significant amount of phosphorus (P). In this study, the characteristics of P compounds in SMC were investigated by the nondestructive X-ray diffraction (XRD) method, chemical extraction, and a cultivation experiment. Only magnesium ammonium phosphate hexahydrate (MAP or struvite, MgNH4PO4·6H2O) was detected as crystal P compound by XRD in most SMC. Furthermore, MAP crystal was observed by scanning electron microscope (SEM) image. The amount of ammonium nitrogen in MAP (MAP-NH4-N) was 3.38 ± 2.24 mg-N g−1 on average, equivalent to 54% of total NH4-N (hydrochloric acid-extractable NH4-N) in SMC. The content of P in MAP (MAP-P) in SMC calculated backward from MAP-NH4-N was 7.5 ± 4.5 mg-P g−1. Sequential water extraction demonstrated that MAP in SMC was dissolved in water. The ratio of MAP-P to water-extractable P (WEP) was 66%, indicating that the amount of WEP was controlled by MAP existence in SMC. The amount of P uptake by the Japanese mustard spinach (Komatsuna; Brassica rapa var. perviridis) plant accorded with WEP content in SMC.
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