Long-Term (1893-2012) Changes In Monthly, Growing Season, and Annual Precipitation Trends and Magnitudes in Central Nebraska

Precipitation has a profound impact on both irrigated and rainfed crop production and hydrological functions of ecosystems in arid, semiarid, humid, and subhumid regions. In arid and semiarid regions, precipitation amount and distribution within the growing season is one of the primary drivers of agricultural productivity. In humid/subhumid regions, even though precipitation is generally adequate for crop production, a few inches of variability (i.e., below or above normal precipitation) can have substantial negative impacts on agro-ecosystem productivity. Small deviations from long-term average precipitation can result in large fluctuations in stream flows and surface runoff, which impact wildlife and natural habitats in wetlands, riparian areas, etc. Effects also may be observed in the amount of water collected in reservoirs, ponds, lakes and other water bodies; and depths to groundwater for irrigation, municipal, recreational, and other uses. Thus, understanding and quantifying the long-term changes in precipitation amount and variability can help managers better evaluate the long-term trends in agricultural productivity. This, in turn, will allow for better assessments in food security, policy decisions, resource assessments, land and water resources enhancement, and management decisions.