Effects of soil renaturalization on organic carbon sequestration and vegetation changes

Abstract

Agricultural producers are encouraged to use non-useful arable land to alter ecological intakes, such as grasslands, and to save the existing tree groups or small forests when the conditions for farming are unfavourable. The aim of this study is to evaluate the changes in the species composition of natural phytoconioses and the SOC sequestration of re-naturalized (1995–2015) arable land, adapting these landscapes as ecological inserts in the low-productivity land of SouthEastern Lithuania (Geoabruptic Haplic Luvisol). Estimating the species composition of abandoned land, it has been determined that over 21 years the species diversity decreased and the weeds typical to arable land disappeared, the invasive Conyza canadensis L. appeared, and the species Festuca arundinacea Schreb. and Dactylis glomerata L. became widespread. Also in the absence of agrarian activity, the processes of rapid overgrow began thus altering the abandoned landscape. The biomass of abandoned land is included in the formation of humic substances and in comparison with arable land agrofitocenose, in this land use, the accumulation of SOC increased by 12 041 kg ha^–1. Compared to arable land, coniferous forests have helped to reduce SOM mineralization and stabilize SOC stocks (decreased only by 257 kg ha^–1) in soil over the past 21 years.