Are K and Na levels in biomass of reed canary grass influenced by grass maturity and in-field leaching

摘要

For improving the properties of grass biomass for combustion, it is important to reduce its concentration of mineral elements, primarily alkaline metals. The objective of this research was to study the effect of grass maturity on K and Na concentrations in the biomass and the leachability of K and Na from the biomass under field conditions. The experiment was carried out on plots with reed canary grass fertilized with mineral fertilizer at a rate of N_(60)P_(30)K_(60)- The harvest was performed at three stages of reed canary grass development: (i) heading, (ii) dough and (iii) ripe seed. After cutting, the biomass was left on the growing site for 14 days. The sampling was done at harvest and 7 and 14 days afterwards. Samples were dried and analysedfor K and Na concentrations. Potassium concentration decreased in biomass with the maturing of the reed canary grass, and it was partly leachable. Sodium concentration in the biomass was low; it did not change during the maturing of grass and did not leach during the post-mowing period. For lowering the K concentration in the biomass, the harvesting should be performed at seed ripening stage and the yield should be left on the field for one week.