Isotopic tracing of phosphorus uptake in corn from ³³P labelled legume residues and ³²P labelled fertilisers applied to a sandy loam soil

Author(s)
Nachimuthu, Gunasekhar
Guppy, Christopher
Kristiansen, Paul
Lockwood, Peter
Publication Date
2009
Abstract
In low input (e.g. organic) farming systems where soil phosphorus (P) fertilisers such as superphosphate are not used, maintaining sufficient available soil P for plant growth can be a major challenge. The use of P accumulating cover crops may increase P availability for subsequent crops. We hypothesised that P release from organic residues of legumes (faba bean ('Vicia faba') and field peas ('Pisum sativum')) could supply adequate P to meet the needs of a subsequent crop in a low P soil. A pot experiment was conducted to determine the contribution of P by legume green manure to subsequent corn using ³³P labelled legume residues and ³²P labelled inorganic fertiliser (KH₂PO₄). The treatments included two rates of P application, (a) 10 kg P ha⁻¹ as legume root and shoot residues or as inorganic fertiliser with and without a C source, and (b) 38 kg P ha⁻¹as a combination of legume shoot and root residues or a combination of root and inorganic fertiliser and inorganic fertiliser alone. An absolute control (zero P) was also used. Shoot dry matter, P uptake and P source (residues or fertilisers) of total P in corn were measured at harvest. Faba bean and field pea residues alone or in combination with fertilisers contributed up to 10% and 5% of the total P uptake by corn respectively, compared with up to 54% by inorganic fertilisers. Incorporation of field pea and faba bean residues with P concentrations higher than those observed under field conditions, may not always lead to adequate net P release to supply the early growth phase of subsequent crops.
Citation
Plant and Soil, 314(1-2), p. 303-310
ISSN
1573-5036
0032-079X
Link
Publisher
Springer Netherlands
Title
Isotopic tracing of phosphorus uptake in corn from ³³P labelled legume residues and ³²P labelled fertilisers applied to a sandy loam soil
Type of document
Journal Article
Entity Type
Publication

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