Harvest in spring improves yield and quality of reed canary grass as a bioenergy crop

Reed canary grass (Phalaris arundinacea L.) is a new bioenergy crop in Swedish agriculture. A new production method was tested where harvest is delayed until the following spring. Four harvest times combined with two nitrogen fertilization levels were studied between 1991 and 1995 in 10 field trials in Sweden. At the end of the growing season, the yield of reed canary grass averaged 8.5 ton DM/ha. In the following spring on average 7 ton DM/ha were harvested as a senescent dry crop. The amounts of plant nutrients removed with the harvested crop in spring were no more than half of the amounts removed with harvest in August. A large portion of the plant nutrients can thus be recirculated in the spring harvest system, which reduces fertilization costs. Concentrations of the undesired elements Cl and K were about 6 times lower in the spring harvest than in the August harvest. The important ash content was lower in the crop at spring harvest than in August, but varied with the soil conditions. The presented results show that a delayed harvest system for reed canary grass is beneficial for both biological production and use of the harvested material for energy purposes.