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Use of the Diagnosis and Recommendation Integrated System with Alfalfa 1
Author(s) -
Russelle M. P.,
Sheaffer C. C.
Publication year - 1986
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1986.00021962007800030036x
Subject(s) - medicago sativa , agronomy , forage , irrigation , nutrient , dry matter , fertilizer , nutrient management , fodder , mathematics , biology , ecology
Improved means are needed to diagnose plant nutrient response to treatments. Our objective was to evaluate the sensitivity of two diagnostic techniques to irrigation, K fertilization, and harvest management of alfalfa ( Medicago sativa L.). Comparison of forage concentrations of essential elements with critical values was not as useful in diagnosing the order of limiting nutrients as were Diagnosis and Recommendation Integrated System (DRIS) indexes. Several elements were present in the forage at concentrations below published critical levels, even at herbage dry matter yields of 13.9 Mg ha −1 . The DRIS indexes reflected the general improvement in nutrient balance resulting from irrigation. Diagnoses based on DRIS indexes were not affected by harvest management, in contrast to the critical value approach. The relationship between the summation of absolute values of DRIS indexes and herbage yield was best described by a power function that incorporated a minimum index value at which yields were no longer limited by overall nutrient balance. The DRIS approach can effectively resolve nutritional responses of alfalfa to fertilizer and irrigation managements in the presence of differing harvest managements