Rainfall patterns in the arid Southwest demonstrate variation on multiple levels. Within the space in one year, there is a predictable cycle of approximately 6 months of spring and summer drought followed by 6 months of fall and winter rains. Layered on top of this pattern of rainfall are the less predictable multi-year cycles of above-average rainfall that are caused by El Nino conditions in the Tropical Pacific Ocean and the Madden-Julian Oscillation that brought high rainfall to the region in 2005. Dependence on irrigation during drought periods leads to the build-up of soil salts during the summer and leaching rainfall in the winter “resets” the soil to more desirable conditions in the spring.

Soil nutritional levels were monitored at golf courses located in the Southwestern U.S. for the past ten years. Soils were analyzed by Brookside Laboratories, New Knoxville, OH and include measurement of phosphorous, potassium, calcium, chloride, magnesium, sodium, sulfate, boron, copper, iron, manganese and zinc as well as electrical conductivity, pH and total exchange capacity. The Madden-Julian Oscillation that delivered above average rainfall to the Southwest region in 2005 reduced average spring fairway soil salinity by 72%, chloride by 92% and sulfur by 89% compared the fall sampling period. The influence of cyclic salinity accumulation and leaching on turfgrass management and turfgrass performance will be discussed.