|CHENDEV, YURY - Belgorod State University|
|Sauer, Thomas - Tom|
|HERNANDEZ, GUILLERMO - University Of Alberta|
|BURRAS, CHARLES - Iowa State University|
Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2014
Publication Date: 1/8/2015
Citation: Chendev, Y.G., Sauer, T.J., Hernandez, G.R., Burras, C.L. 2015. History of east European chernozem soil degradation: Protection and restoration by tree windbreaks in the Russian steppe. Sustainability. 7:705-724. DOI:10.3390/su7010705.
Interpretive Summary: Sustaining soil resources is a complex undertaking as any activity has long-term effects that may change with time. This study addresses the history of land use in the Russian steppes and how land use affected soil resources. Prior to human intervention, this area was a semi-arid grassland. Cultivation of crops started about 150 years ago. Although the soils are deep and fertile, wind and water erosion and poor farming practices led to widespread low productivity. Beginning in the early 20th century, a program of tree windbreak planting began to help protect soils in the region and to rehabilitate soils that were already degraded. Tree windbreaks modified the local microclimate ensuring higher and more consistent crop yields by reducing the effects of drought. Better crop growth improved soil protection as the soil has greater plant or plant residue cover to protect it from wind and water erosion. This program of tree planting continues as recent studies have identified positive changes in soil organic matter and related properties associated with tree windbreaks within crop fields. This research is of interest to scientists, managers, and policy makers as it demonstrates the long-term positive impact of field windbreaks on crop production and soil protection.
Technical Abstract: The physiographic region of the Central Russian Upland, situated in the Central part of Eastern Europe, is characterized by the most fertile grassland soils – Chernozems (Mollisols in the USDA taxonomy). However, over the last several centuries this region has experienced intense land-use conversion. The most widespread and significant land-use change is the extensive cultivation of these soils. As a result, Chernozems of the region that were some of the most naturally fertile soils in the world with thick A horizons had become, by the second half of the 19th century, weakly productive, with decreased stocks of organic matter. When not protected by plant cover, water and wind erosion degraded the open fields. The investigation of methods for rehabilitation and restoration of Chernozems resulted in the practice of afforestation of agricultural lands (mainly by windbreak planting). Preferences of agroforestry practices were initially connected with protection of cropland from wind and water erosion, improvement of microclimate for crop growth, and providing new refugia for wild animal and plant habitats. During the last several decades, tree windbreaks have begun to be viewed as ecosystems with great potential for atmospheric carbon sequestration, which plays a positive role in climate change mitigation. For the evaluation of windbreak influence on Chernozem soils, a study was developed with three field study areas across a climatic gradient from cool and wet in the north of the region to warm and dry in the south. Windbreak age ranged from 55-57 years. At each site, soil pits were prepared within the windbreak, the adjacent crop fields of 150 years of cultivation, and nearby undisturbed grassland. Profile descriptions were completed to a depth of 1.5 m. A linear relationship was detected between the difference in organic-rich surface layer (A + AB horizon) thickness of soils beneath windbreaks and undisturbed grasslands and a climate index, the hydrothermal coefficient (HTC). These results indicate that windbreaks under relatively cooler and wetter climate conditions are more favorable for organic matter accumulation in the surface soil. For the 0-100 cm layer of the Chernozems beneath windbreaks, an increase in organic C stocks comparable with undisturbed grassland soils (15-63 Mg ha-1) was detected. Significant growth of soil organic matter stocks was identified not only for the upper 30 cm, but also for the deeper layer (30-100 cm) of afforested Chernozems. These findings illustrate that in the central part of Eastern Europe tree windbreaks improve soil quality by enhancing soil organic matter while providing a sink for atmospheric carbon in tree biomass and soil organic matter.