Response of WW-517 Old World Bluestem to Fertilization, Watering, and Clipping

Abstract

An experiment (TUBE) was conducted to evaluate the effect of two levels of fertilizer, two levels of watering, and clipping on dry matter (DM) and crude protein yield, water use efficiency (WUE), and end of season root weights of WW-517 Old World Bluestem (OWB) (Bothriochloa intermedia var. indica) established in plastic tubes buried in the soil. A second experiment (MICRO PLOT) evaluated dry matter and crude protein yield of OWB, in 2.7 ft² plots within a two year old grass stand, at two levels of fertilizer and five clipping regimes. In the TUBE experiment, fertilization had no effect on leaf yields, but the wet-clipped treatment increased leaf yields 40% compared to dry-unclipped plants. Level of fertilizer applied did influence OWB stem, top-growth (aboveground portion less stubble), and aboveground yields. The wet-fertilized-clipped treatment increased top-growth and above ground yields by 54 and 49% when compared to dry-unfertilized-unclipped plants. Frequency of watering, unlike fertilization or clipping, did not significantly influence OWB WUE. Water use efficiency of OWB, averaged across watering regimes, was 1.2 and 0.7 g DM/L water for fertilized-clipped and nnfertilized-unc1ipped plants, respectively. Leaf crude protein yield of wet-fertilized plants was at least 35% greater than other treatments. End of season root weights increased with frequency of watering, but declined with fertilization and clipping. In the MICROPLOT experiment, leaf, top-growth, and crude protein yields were enhanced by fertilization and clipping. Results from this study indicate fertilization coupled with clipping at proper intervals increased aboveground plant yield and nutritive value. Response to these treatments was further enhanced with addition of water. In contrast, root weights were reduced following fertilization and clipping. Reduction in root weights, likely decreased the volume of soil from which plants could extract water and nutrients and may ultimately have an adverse affect on plant vigor.