In:
Journal of Plant Nutrition and Soil Science, Wiley, Vol. 178, No. 4 ( 2015-08), p. 555-566
Abstract:
Low molecular weight organic acids exuded by plants roots enhance inorganic P i release into soil solution and thereby increases plant‐available Pi in soils. Low molecular weight organic acids may also induce organic P (P o ) release into soil solution, but kinetics of both Pi and Po displacement from the soil matrix into soil solution of agricultural soils is poorly understood, and the mechanism for P o release is not well explained. This study used kinetic experiments to determine the concentrations and release rates of P i and P o induced by oxalic acid, citric acid, and malic acid in calcareous, neutral and acidic soils. Kinetic data were well described by Elovich ( r 2 = 0.801–0.993, P 〈 0.001) and power functions models ( r 2 = 0.721–0.977, P 〈 0.001). Low molecular weight organic acids at 10 mmol kg −1 soil induced the exponential release of both P i and P o , which reached a plateau approx. 480– 2,880 min after the start of the experiment. Cumulative P o release induced by low molecular weight organic acids was ranked as oxalic acid (0.63–3.17 mg kg −1 ) 〉 citric acid (0.61–2.82 mg kg −1 ) 〉 malic acid (0.52–1.76 mg kg −1 ) and mainly resulted from the release of labile P o (NaHCO 3 ‐P o ) regardless of soil type. By contrast, oxalic acid was most effective in enhancing P i release from the HCl‐P i (Ca‐P i ) fraction of the calcareous soil, and citric acid was most effective in releasing P i from the NaOH‐P i (Fe/Al‐P i ) fraction of the neutral and acidic soils. Therefore, the mechanism for the kinetics of P o release induced by low molecular weight organic acids is ascribed to their ability to mobilize the labile P o (NaHCO 3 ‐P o ) rather than their ability to chelate cations ( i.e. , Fe 3+ , Al 3+ ) bound to P o in soil.
Type of Medium:
Online Resource
ISSN:
1436-8730
,
1522-2624
DOI:
10.1002/jpln.201500047
Language:
English
Publisher:
Wiley
Publication Date:
2015
detail.hit.zdb_id:
1481142-X
detail.hit.zdb_id:
1470765-2
SSG:
12
SSG:
13
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