Diagnostic nitrogen concentrations for cabbages grown in sand culture
1989
Huett, D.O. (New South Wales Agriculture and Fisheries, Alstonville (Australia). Tropical Fruit Research Station) | Rose, G. (New South Wales Agriculture and Fisheries, Wollongbar (Australia). North Coast Agricultural Inst.)
From outdoor lysimeter experiments the relationship between growth rate relative to the maximum at each sampling time and leaf N concentration was used to derive diagnostic petiole sap nitrate-N, leaf nitrate-N and total N in the youngest fully opened leaf (YFOL), the youngest fully expanded leaf (YFEL) and the oldest green leaf (OL) and bulked leaf total N concentrations. Critical concentration corresponded to 90 percent maximum growth rate and adequate concentration corresponded to 91-100 percent maximum growth rate. The concentrations of K, P, Ca, Mg and S in YFOL, YFEL, OL and bulked leaf corresponding to N treatments producing maximum growth rates are also presented.
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