The effect of total water supply, and frequency of application, upon lucerne. II.* Chemical composition

Abstract

Total water supply, expressed as a proportion of class A pan evaporation (E_pan), and frequency of water application were varied independently during summer. The phosphorus concentration in the shoots of lucerne increased by 35% when the total water supply was increased from 0.1 to 1.0E_pan; the nitrogen concentration was not significantly affected. The in vitro digestibility of leaf and stem fractions decreased with increasing total water supply, and the proportion of highly digestible fractions (leaf and flower) also decreased, so that total shoot digestibility decreased from 65% at 0.24 E_pan to 55% at 0.58 E_pan. Frequency of water application had no significant effect upon phosphorus or nitrogen concentration or in vitro digestibility.

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*Part I, Aust. J. Agric. Res., 23: 239 (1972)