Effects of land use and agricultural management systems on wind erosion along a climate gradient in the dry steppe (ReKKS) 01.08.2017 – 31.12.2022

In the steppe regions of Kazakhstan and south-west Siberia, climate change and intensive agricultural use are causing soil degradation. Innovations for the sustainable use of agricultural resources can solve this problem. In the ReKKS project, German, Kazakh and Russian partners are working closely with local partners to develop and implement innovative, sustainable and climate-friendly agricultural concepts and methods to minimise soil erosion and improve the water, nutrient and carbon balance.

Background and goals

Wind erosion is a persistent problem in the dry steppe of Kazakhstan. Continuous erosion, transport and deposition of soil material by wind is a major cause of humus loss and soil degradation on agricultural land. The type and intensity of land use are the main causes of erosion. Open areas with a flat relief in particular are subject to a high risk of erosion. In extreme cases, wind erosion leads to the loss of usable arable soils by impairing their water and nutrient storage and carbon sink functions. Reducing wind erosion is a key objective of climate-optimised soil cultivation, which not only serves agriculture, but also soil and climate protection and sustainable ecosystem development in temperate steppes.

For geoecologists, the overarching goals are

• To visualise spatial patterns of wind erosion disposition as a function of climate, soils and land use along a climatic gradient in the dry steppe.
• Identification of control variables of wind erosion and assessment of wind erosion disposition along this gradient.
• Quantification of the effects of land use and arable farming systems on wind erosion at site and regional scales.
• Identification of optimal land use and arable farming systems to reduce soil and humus losses due to wind erosion.
• Development of training materials and modules.

Methodological approach

• Laboratory methods: Physico-chemical soil analyses (texture, aggregate stability, organic matter, etc.)
• Field experiments: Mobile wind tunnel, erosion traps
• Modelling
• Remote sensing

Comparative texture and carbon analyses of the soil in the erosion zone and in the sediment trap are aimed at assessing the selective erosion of certain grain sizes as well as the contribution of wind erosion to humus losses due to use and the resulting general impairment of site quality. Based on this, the aim is to provide information and recommendations for action for site-adapted, climate-optimised agricultural use of the dry steppe while minimising soil and humus losses due to erosion.

In order to evaluate the success of erosion-minimising management systems, it is necessary to establish an in-situ system to analyse sediment transport caused by wind erosion and to quantify the sediment load under varying landscape and usage conditions. A mobile wind tunnel makes it possible to quantify soil erosion depending on the control variables: meteorological conditions, soil properties, soil moisture, crop type and tillage.

Results

1. Agricultural steppe soils are susceptible to wind and water erosion. In particular, the decomposition of aggregates during snowmelt favours subsequent soil loss due to wind erosion.
2. The high mechanical stress during seedbed preparation causes heavy soil loss due to wind. In this context, ruts and unpaved roads are an underestimated source of erosion.
3. Material eroded by the wind is enriched with organic carbon. The loss of the most important binding agent indirectly increases the erosion processes and could lead to unforeseeable consequences in the carbon cycle.

The results provide an important basis for demonstrating the efficiency and innovative power of the cultivation methods developed and the use of modern environmental monitoring systems and agricultural technology. Recommendations were derived from the results that lead to a reduction in the risk of wind erosion of agricultural land and to adaptation measures to climate change in the study regions.