Assessing the depletion of soil P following sequential extractions with Mehlich-3 and Olsen solutions.

Messiga, A.J., Ba, Y., Ziadi, N., Bélanger, G., and Lafond, J. (2014). "Assessing the depletion of soil P following sequential extractions with Mehlich-3 and Olsen solutions.", Archives of Agronomy and Soil Science, 60(10), pp. 1445-1458. doi : 10.1080/03650340.2014.884709  Access to full text

Abstract

We analyzed in soils with contrasting cultivation histories the depletion of P following sequential extractions with soil testing solutions. Soil samples were collected in three experiments in eastern Canada (L’Acadie, Lévis, and Normandin) and P was sequentially extracted 16 times, once daily, using Mehlich-3 (M3) or Olsen (Ol) solution. The cumulative amount of P extracted was 252 mg P{SUB}M{/SUB}3 kg1 and 77 mg kg1 P{SUB}O{/SUB}l for L’Acadie, 212 mg P{SUB}M{/SUB}3 kg1 and 66 mg P{SUB}O{/SUB}l kg1 for Lévis, and 424 mg P{SUB}M{/SUB}3 kg1 and 83 mg P{SUB}O{/SUB}l kg1 for Normandin. The depletion of P was described by a logarithmic function (Y = a ln (N) + b) for P{SUB}M{/SUB}3, and a power function (Y = αN{sup}β{/sup}) for P{SUB}O{/SUB}l. The inorganic P pool decreased in the three soils. The organic P pool did not decrease possibly because soil testing solutions did not directly extract P from this pool. This study demonstrated that laboratory soil testing analysis using M3 or Ol solution principally target P from the inorganic pool, suggesting that P fertilizer recommendations to mineral soils relying on these methods do not account for the potential of the organic P pool to contribute to soil P availability.

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