The research was carried out to determine the effects of soil pH (or liming) and nitrogen (N) fertilization on the common mugwort (Artemisia vulgaris L.) and cup plant (Silphium perfoliatium L.) dry mass (DM) yield, calorific value and mechanical properties. Field experiments were set up in 2008 in Western Lithuania on a naturally acid (pH 4.2-4.4) moraine loam. According to the averaged data of four experimental years, the highest DM yield 4100 kg ha -1 of common mugwort was established in 2009, which significantly decreased in the subsequent years. And, conversely, the highest cup plant DM yield 17980 kg ha -1 was obtained in 2011. An increase in soil pH from 4.2-4.4 up to 5.6-5.7, resulting from 6.0 t ha -1 CaCO 3 application, increased cup plant DM yield by 27.4%. Fertilization with 120 kg ha -1 N significantly increased common mugwort and cup plant DM yield by 34.5% and 26.7% respectively, compared with the treatment without N fertilization. We also studied the chopping quality of common mugwort and cup plant and chaff fractional composition using sieves with different mesh sizes. The chaff of cup plant was finer and more even, and thus more suitable for use for energy purposes. Plant milling quality showed cup plant particles to be smaller and more even too, and thus better suited for pressing and combustion. The highest calorific value of common mugwort (17.97 MJ kg -1 ) was obtained in 2010 and that of cup plant (17.48 MJ kg -1 ) in 2012. The calorific values of common mugwort and cup plant were influenced most by the year of cultivation and 120 kg ha -1 N application.

Investigations on phosphorus (P) distribution in a naturally acid and limed moraine loam, Bathypogleyic Dystric Glossic Retisol were conducted in a site of a long-term experiment at the Vėžaičiai Branch of Lithuanian Research Centre for Agriculture and Forestry in 2008 and 2011. The aim of the present study was to determine the distribution of different phosphorus forms and fractions in naturally acid soil limed for a long time (62 years). During this study different amounts (18.4 and 104.9 t ha -1 ) of lime materials were incorporated into the soil and affected the formation of two soil pH KCl levels -acidic (5.6) and near to neutral (6.7). Seven different organic and mineral phosphate fractions and plant-available phosphorus were determined in the soil. The long-term soil liming was found to have no significant effect on the total P content and its distribution, but caused the changes in the proportions between the different phosphorus forms. Major part of mineral (74.02-83.68%) and organic (88.9-93.8%) P was composed of Al and Fe phosphates. Soil liming using ×2.0 liming rates every 3-4 years influenced a significant increase of the phosphates (AlPO 4 and Al(Fe)PO 4 ) little-available to plants obtained by the second cycle of extraction. It was determined that when soil pH becomes near to neutral, water soluble and plant-available P increases compared to its value measured at native pH. Increase of soil pH KCl till 6.7 had a significant effect on the amount of little plant-available Ca phosphates and less soluble organic phosphorus fraction amount in soil. The relatively optimal amounts of phosphorus fractions available for plants were determined in the soil with a pH KCl of 5.6, achieved by liming with a 0.5 rate every 7 years.

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