Arid land conversion

Impact of major land use changes, including conversion to agricultural lands

Arid and semi-arid regions cover about 40% of the earth's surface. Many of these areas have experienced major land use changes, including conversion to agricultural lands. Irrigated agriculture is likely to impact soil chemical, physical and biological properties. For instance, large water additions through irrigation may affect salt levels and mineral weathering while changes in vegetation from shrubs to agricultural crops may affect quantity and quality of organic matter in the soil.

Understanding how management affects soil properties is important because management practices may have to change over time depending on how soils develop in response to management activities. In addition, in Nevada many agricultural fields are taken out of production and are being restored to native vegetation. Potentially, over time the soils have changed so much that they are not suitable to support native vegetation anymore which may explain why restoration efforts have had limited success.

Our study compares soil properties in native shrublands with soils in areas that have been cropped with alfalfa for more than five decades. We are combining field with laboratory studies focusing on soil chemical and biological properties. The results of this study will help us understand how fast soil properties can change in response to management and determine if these changes may be reversible or not.

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