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TY - JOUR AU - Gourley, C. J. P. AU - Allan, D. L. AU - Russelle, M. P. PY - 1993 DA - 1993/10/01 TI - Defining phosphorus efficiency in plants JO - Plant and Soil SP - 289 EP - 292 VL - 155 IS - 1 AB - The many different definitions for "nutrient efficiency" make the use of the term ambiguous. We evaluated nutrient efficiency using data from a study of response to phosphorus (P) supply in white clover (Trifolium repens L.) and lucerne (Medicago sativa L.). Application of various criteria identified in the literature as measures of nutrient efficiency did not clarify differences between purportedly P efficient and inefficient germplasm. Germplasm differed in maximum shoot and total dry mass and in solution P concentration ([P]s) required to achieve 80% maximum yield, but not in P concentration of tissue ([P]t), internal P utilization, or P uptake per unit of fine root dry mass. Differences in yield may have resulted from factors other than efficient use of P. To reduce the confounding effects that other factors have on nutrient efficiency, it is essential that equivalent yields of germplasm be demonstrated where nutrients are not limiting. Mechanisms that enable enhanced nutrient efficiency can be identified less ambiguously using this approach. SN - 1573-5036 UR - https://doi.org/10.1007/BF00025039 DO - 10.1007/BF00025039 ID - Gourley1993 ER -