Supervisory Research Soil Scientist
Water Management & Conservation Research Unit
USDA-ARS, US Arid-Land Agricultural Research Center
Site-specific nutrient (especially nitrogen (N)) management for irrigated cotton, wheat, sorghum, lesquerella, camelina, and guayule. Small grain cover crops and conservation tillage. Proximal sensing of canopy reflectance, canopy height, and canopy temperature. Petiole-nitrate analysis, leaf N testing, and chlorophyll meter measurements. Pre-plant soil profile nitrate testing. Spatial analysis of soil properties, and plant N status for in-season N management, variable-rate fertilization, N fertigation for surface, center-pivots and subsurface drip irrigation systems. Chemical drip irrigation system maintenance. Nitrogen cycling in soils, crop N use efficiency, 15N studies, N mineralization, denitrification, and nitrate leaching. Carbon sequestration and soil quality. Water quality. Nitrogen cycling and management in wastewater. Ammonia volatilization. Greenhouse gas emissions from soils, especially nitrous oxide. Irrigation management and efficiency. Water balances. Life cycle analysis. Phone apps and calculators for nitrogen and water management. International agriculture, especially central, east and west Asia.
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