Effects Of Cultivating Management Measures On The Growth And Energy Production Efficiency Of Triarrhena Sacchariflora (Maxim.) Nakai

Sugarcaneflower silverreed (Triarrhena sacchariflora (Maxim.) Nakai) is a C₄ rhizomatous perennial grass originating from the Eastern Asia. Its great adaptability to different environments, high yielding potential, and good combustion quality makes it one of the most ideal crops for energy production. In greenhouse, the effects of soil water content on the growth and biomass characteristics of Sugarcaneflower silvergrassreed were studied. In field experiment, the growth and biomass characteristics and energy production efficiency of Sugarcaneflower silverreed were investigated under two different irrigation level (A₁=80, A₂=0mm), and three different fertilization (Complex fertilizer, N: P: K=20: 12.5: 10) applications (B₁=0, B₂=375, B₃=750 kg·ha^-1) and four different planting densities (M₁=4, M₂=2, M₃=1.33, M₄=1 plants·m^-2). The following results were obtained:1 Growth characteristics The growth of Sugarcaneflower silverreed was truly affected by soil water content, fertilization and plant density. Along with the decline of soil water contents, the aboveground morphological parameters, e.g. height, leaf area, tiller number et al., and the biomass accumulation at elongation stage decreased significantly; the biomass accumulation was not severely stunted under light water stress (60% of soil relative water contents, RWC). The proportion of the underground biomass and the ratio of root to shoot increased significantly following the decrease of soil water content.Along with the increase of fertilization applied and planting density, the height and leaf area index increased significantly, reaching maximum values at heading stage. At 144d after planting the angle between the stem and leaf petiole decreased gradually from the lower canopy to the upper canopy. The leaf angle of upper canopy decreased gradually following the increase of fertilization applied and planting density; at same time, the dry matter yield increased significantly. Under treatments of 2 plants·m^-2, A₁B₂, and A₁B₃, the structures of canopy were superior to other treatments.2 Biomass characteristics There were significant effects of soil water content on the biomass characteristics of Sugarcaneflower silverreed. The concentrations of ash, potassium and chlorine in stems and leaves increased while the volatile and nitrogen dropped along with the decrease of soil water content. The biomass quality was improved under light water stress.There were significant effects of irrigation, fertilization and plant density on the concentrations of industrial component and mineral element of Sugarcaneflower silverreed, while the concentration of chemical component was not severely impacted. Along with the increase of plant density, the concentrations of plant water, potassium and chloride in stems and leaves increased, nitrogen and sulfur in stems increased, while nitrogen and sulfur in leaves decreased. Under treatment A₁, the gross caloric value (GCV) of aboveground biomass, potassium in leaf, and chlorine in stem decreased significantly, while the concentrations of potassium in stem and chlorine in leaf increased significantly. The lowest chlorine content in leaf was obtained under treatment B₂. There were no significant effects of irrigation and fertilization on the sulfur content in stems and leaves. Along with the increase of fertilization applied, the concentration of ash in stems and leaves decreased significantly, but no significant difference between treatment B₂ and B₃. The highest hemicellulose content and lowest lignin content were obtained by treatment B₂. Moreover, the mineral content in leaves was larger than that in stems.Although delayed harvest in winter or just before shoot emergence in spring reduced moisture contents and mineral element content significantly, the biomass yield reduced substantially. There is on significant effect of delayed harvest on the sulfur contents in stems and leaves.From the view of application, the planting density of 1 or 2 plants·m^-2 of Sugarcaneflower silverreed for biofuel feedstock was superior to the 1.33 and 4 plants·m^-2, and the appropriate combinations of irrigation and fertilization were A₁B₂ and A₂B₂; the best harvest time was in Winter. However, for the purpose of liquescence utilization of Sugarcaneflower silverreed, the better plant densities were 1.33 plants·m^-2 and 2 plants·m^-2, the better irrigation and fertilization combinations were A₁B₂ or A₁B₃ which have lowest lignin and highest hemicellulose contents; the best harvest time was in Autumn.3 Energy production efficiency The whole seasonal radiation use efficiency was truly affected by irrigation, fertilization and plant density. Along with the increase of irrigation, fertilization and plant density, the photosynthetically active radiation use efficiency and total radiation use efficiency increased significantly. The plant density for highest net energy production was 4 plants·m^-2, secondly 2 plants·m^-2, the lowest one was 1 plant·m^-2, while the coefficient of energy consumption was contrariwise. The combination of irrigation and fertilization treatments for highest net energy production was A₁B₃, the lowest one for net energy production and the coefficient of energy consumption was A₂B₁).Generally, the appropriate plant density for both high energy production efficiency and good combustion qualities was 2-4 plants·m^-2, and the better combinations of irrigation and fertilization were A₁B₁, A₂B₂ and A₁B₂. The best harvest time was in winter. The high energy production efficiency and good biomass characteristics of Sugarcaneflower silverreed in Northern China makes it one of the promising crops for energy production.