Abstract
A two-year nutrient omission trial was conducted on semiarid wasteland to determine the effects of nitrogen (N), phosphorus (P), and potassium (K) on the chemical composition and theoretical ethanol yield (TEY) of switchgrass (Panicum virgatum L.). The fertilizer treatments were the following: NPK, PK, NK, NP, and no nutrient inputs (CK). Results indicated that the crude protein (CP) content and protein yield of switchgrass aboveground biomass decreased significantly in the PK treatment (N omission) and the CK, compared with the NPK treatment. The omission of N, P, or K did not significantly affect the other feed and energy quality indicators. When averaged across the two years, the neutral- and acid-detergent fiber contents were lower in the NPK and NP treatments, but the CP, dry matter digestibility, dry matter intake, total digestible nutrients, net energy for lactation, and relative feed value were higher, indicating that the suitable application with combination of N and P was helpful to improve the forage quality of switchgrass. In PK and CK treatments, the contents of soluble sugar, cellulose, and hemicellulose were higher but that of ash was lower than that in other three treatments, indicating that no N application meant better quality of switchgrass aboveground biomass for bioethanol production. The TEY at NPK was 2532 L ha−1 in 2015 and 2797 L ha−1 in 2016; in particular, the TEY decreased significantly by 15.1% in PK, 14.7% in NK, 10.5% in NP, and 29.9% in CK in 2016. To conclude, N was the most limiting factor in switchgrass productivity and the combined N, P, and K nutrient supply management strategy is recommended based on the consideration of quality and quantity of switchgrass as forage and bioenergy feedstock on semiarid marginal land.
Highlights
Switchgrass (Panicum virgatum L.) is a perennial C4 grass widely distributed in North America
The most desirable characteristics of switchgrass, when it is considered as a bioenergy feedstock, include its low input requirements, high biomass yield potential, and high cellulose but low lignin and ash contents [4,5]
Agronomy 2020, 10, 1147 such as a high crude protein (CP) content and quality of fibers, switchgrass aboveground parts are widely used as forage [6]
Summary
Switchgrass (Panicum virgatum L.) is a perennial C4 grass widely distributed in North America. In recent years, it has been successfully introduced in northern China [1,2]. The most desirable characteristics of switchgrass, when it is considered as a bioenergy feedstock, include its low input requirements, high biomass yield potential, and high cellulose but low lignin and ash contents [4,5]. The sustainable development of switchgrass on marginal lands at low-cost and with high-yielding biomass feedstock of desirable quality is currently a promising solution to address the China’s increasing demand for bioenergy feedstock, as well as to overcome the country’s shortages of forage. Poor infrastructure and soil fertility are problems that face crop production on marginal lands, resulting in a lower biomass quality and yield compared to the same crop grown in normal croplands [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
