Abstract:
The main research emphasis on switchgrass (Panicum virgatum L.) in the USA is as
lignocellulosic bioenergy feedstock. However, early harvest of switchgrass can be used for
animal feed leaving the late growth for bioenergy feedstock. However, soil fertility status can
affect quality biomass production. The objective of this experiment was to determine the effect
of cattle manure (CM), poultry litter (PL), urea, combined NPK chemical fertilizer, inter-seeded
crimson clover (Trifolium incarnatum L.) and control on biomass and selected qualities of early
harvest switchgrass for animal feed. When average over years, the mean dry biomass yield at
Lake Carl Blackwell (LCB) was 17% greater than Perkins. But the crude protein concentration at
Perkins was 20% higher than LCB perhaps due to dilution effect. Over years and sites,
switchgrass biomass yields and qualities were improved with the application of nutrients. The
dry biomass and crude protein concentration for the nutrient sources ranged from 6,974 to 10,618
kg ha-1
and from 6.2 to 7.7 %, respectively. Application of PL increased dry biomass yield and
crude protein concentration by 52 and 24% over the control treatment, respectively. Application
of PL and CM produced improved crude protein concentration without biomass yield tradeoff
compared with chemical fertilizer applications. This result is promising to enhance quality forage
production and promote nutrient re-cycling. However, economic analysis and monitoring of PL
and CM application are needed to determine profitability and ensure environmental
sustainability, respectively. |
