Low plant available phosphorus limits legume growth and biological nitrogen
fixation (BNF). This study examined, under controlled conditions, the relationship
between soil phosphorus and alfalfa and soybean BNF on two contrasting low-P soils
(Ontario and Nova Scotia) from organic dairy farms. Soluble P was applied up to 135
mg P kg-1. An optimum range of 45 to 90 mg kg-1 applied P increased soybean plant
growth, nodulation, N and P uptake and BNF. Significant effects of soil type reflected
greater N supplying ability and lower P sorption for the Ontario soil. Alfalfa response to
soluble P application was not as apparent. In addition three potentially organically
acceptable amendments (MSW compost, Crystal Green® struvite and partially solubilized
rock phosphate) were evaluated as alternate sources of plant available P. Compost and
struvite, applied at moderate rates, sufficiently supplied P to increase plant growth and
BNF comparably to that found for soluble P fertilizer.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:NSHD.ca#10222/13347 |
| Date | 20 November 2010 |
| Creators | Ward, Amanda |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
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