The effect of cutting height and cutting frequency on Panicum coloratum L. and the interrelationship of leaf age and photosynthesis

Parameters of yield, tiller number, leaf area, and crown weight were studied for a 20-week period on kleingrass (Panicum coloratum L.) which was varied as to the dates at which it was first cut and the frequency and height at which it was clipped. The percent total available carbohydrates of plant crowns were determined on selected treatments by hydrolysis with 0.2N H ₂SO ₄. Yield, tiller number, leaf area, and crown weight had higher totals for the 20-week period when the initial cut occurred at the heading stage of growth instead of at the mature seed stage. These higher totals were due to an additional harvest in the early initial cut. However, by delaying the initial cut of kleingrass plants until the mature seed stage, the plants became better established and produced a larger crown frame. Plants clipped at different frequencies differed in yield and tiller number at the early initial cut only and in leaf area at the early and late initial cut. Crown weights of the plants increased with decreasing cutting frequency. Leaf area remaining on the stubble was affected by frequency only at the high cutting height during the first half of the defoliation period. Plants which were cut at either 4- or 5-week frequencies generally produced similar responses, while those clipped at a 3-week frequency had less yield, tillers, leaf area, and crown weight. During the latter part of the defoliation period, plants cut most frequently increased in percent TAC...