| A wood-grass biomass energy plantation was installed at the Genetics Field Station, Tully, New York in the spring of 1987. Annual and seasonal changes in willow growth, biomass production, nutrient accumulation and nutrient use efficiency were examined for three years. Comparison among five willow clones and one hybrid popular clone; planting density; N, P and K fertilizer application; and years were made in this study.; Hybrid poplar clone NM5 (Populus nigra x maximowiczii) had significantly higher biomass production compared to all willow clones in the first year. In the second year willow clone SV1 (S. viminalis) and poplar clone NM5 produced the highest biomass yield and had a higher nutrient use efficiency than all other clones. Willow clone SV1 produced the highest biomass yield in the third year and had a higher nutrient use efficiency than all other clones. Without fertilizer applied, NM5 and SV1 produced the greated biomass in 1989.; Three planting densities (15cm x 15cm, 30cm, x 30cm, and 46cm x 46cm) were examined. Trees in highest density plots (15cm x 15cm) produced larger amounts of biomass in the first year. Space and light competition limited tree growth in the third year in the highest density plots. Trees in the lowest density plots (46cm x 46cm) produced more biomass than trees in the highest density plots in the third year.; Although large amounts of the nutrients were returned to the site through leaf fall, nitrogen and phosphorus were retranslocated to root and stool during leaf fall.; Nitrogen, phosphorus and potassium fertilizer application had no effect on biomass production during the first growing season because nutrients contained in the cutting and/or initial soil fertility were adequate for the small amount of biomass produced with limited root systems. In the second year, water was believed to be the major factor limiting growth. During the third year, with irrigation, fertilization with N, P and K increase willow biomass production. Nitrogen was the major growth limiting factor in the third year.; During the third growing season of this study, the best willow clone SV1 produced 15 odt ha{dollar}sp{lcub}-1{rcub}{dollar} yr{dollar}sp{lcub}-1{rcub}{dollar} of biomass. It is expected that with adequate growing space, fertilization and irrigation, production of 20 odt ha{dollar}sp{lcub}-1{rcub}{dollar} yr{dollar}sp{lcub}-1{rcub}{dollar} or biomass could be achieved. |
