INTERACTION BETWEEN NITROGEN AND WATER IN GROWTH OF GRASS SWARDS .2. LEAF AREA INDEX AND NET ASSIMILATION RATE

The effect of nitrogen fertilizer and irrigation treatments on the leaf-area index (L) and net assimilation rate (E) of a monthly cut sward of Italian ryegrass (Lolium multifolium) is considered. Response to nitrogen was due to increase in both L and E, whereas response to irrigation was largely due to increase in L. The data show little evidence of a seasonal decline in E. This may have been due to the mid-season replacement of old tillers by new, and by the encouragement to new leaf production caused by periodic harvesting. © 1969, Cambridge University Press. All rights reserved.