AGRARINIŲ ŽEMIŲ RENATŪRALIZACIJOS LIETUVOJE APŽVALGA.

This article discusses the recent changes in agricultural landuse and soil renaturalization processes in Lithuania. The paper briefly presents renaturalization research currently carried out in Lithuania and analysis of recent changes in arable land. Although renaturalization research in Lithuania is relatively young, but area of agrarian soils in Lithuania affected by renaturalization processes is huge (about 1 million ha according to year 2005 estimates). According to statistical land-use data and land-use surveys, area of arable land decreases every year, and the annual change ranges from -1% (in 1990-1991) to 10% (in 2005). Certain cycles of changes are obvious: from 1990 to 1995 the decline in arable lands was faster. There was noticeable slowdown in the period up to 2002, followed by sudden acceleration reaching its peak in 2005. During the last five years the situation has stabilized with arable land decreasing annually by 3-4%. It is believed that in different parts of Lithuania renaturalization processes currently progress quite rapidly and this trend will continue in future. Some scientists predict that with development of unconventional or even nonagrarian farming the agrarian landscape that dominated for centuries should be gradually replaced by forested landscape. Obviously, for the optimization of agrarian land use and planning of changes in it permanent long-term research is needed, from registration of annual changes to long-term monitoring of soil status. Thus the linking of causes and effects of re-naturalization processes with extent of actual changes in agricultural land and the summarized knowledge of various fields of science are preconditions for costefficient and naturally optimized soil renaturalization regulation. Pedological soil renaturalization research mainly focused on southern and south-eastern Lithuania characterised by low productivity and diverse soil cover. Studies carried out deal with a variety of potential transformations of arable land use, including grassland, afforestation, or even effects of long-term fallowing on pedological properties, soil properties change and nutrient circulation and energy, moreover, these studies also deal with bio-diversity issues. Studies at the Institute of Agriculture and Forestry have revealed that soil renaturalization significantly changes chemical and microbiological parameters of soil. The analyzed parameters include soil pH, P and ? mobile, organic carbon, total nitrogen and soil microbial properties. However, studies based on total or mobile mineral nutrients analysis, and soil organic carbon status remain largely uncovered. Complex field and laboratory studies on soil organic carbon (DOA) and nutrient content of organic and mineral forms (oNPS) by using different methods of soil renaturalization and soil carbon change prediction modelling have recently been started at the Vokė Branch of LRCAF. Previously such studies in Lithuania were only occasional, therefore now they will make an important contribution to devising scientifically based, rational and optimized land use strategy. The authors of the article summarize that in one way or another renaturalization processes have affected about 15% of the land in Lithuania, but they have been differently evaluated by specialists in different fields. Pedological renaturalization studies gain practical significance because of Lithuania's international obligations in the struggle against climate change. [ABSTRACT FROM AUTHOR]