Commercially Available Products to Increase Soil Water-Holding Capacity for Gardens and Landscapes Shital Poudyal, Jake Powell, Rowe Zwahlen, and edited by Grant Cardon
Introduction The amount of water retained in a landscape is influenced by various factors, such as irrigation scheduling, existing slopes, and soil type. For instance, soil rich in clay may produce considerable runoff during an irrigation event, while soil dominated by sand may experience significant leaching. Given the water scarcity becoming more prevalent in Utah's semiarid climate, even small reductions in irrigation water usage can be highly beneficial. In the Beehive State, we have soils ranging from clay-dominant soils to sand-dominant soils. Sandy soils are characterized by high sand content, resulting in a limited capacity to hold water. The soil's water-holding capacity refers to the amount of water that can be retained by the soil and used by plants. Larger sand and silt particles tend to be inefficient at holding water. One of the most common and easy ways to increase soil water-holding capacity is incorporating organic matter into the soil. Adding organic matter provides absorptive surfaces and creates numerous micropores in the soil, aiding water retention. Adding just 1% organic matter to the soil can allow for an additional storage of 2,000 to 2,500 gallons of water in a 5,000 square foot garden, with the greatest benefits observed in sandy or coarse-textured soils. There is plenty of information on adding organic manure and compost, so we will exclude those from our discussion, but here are a few Utah State University (USU) Extension resources: ⢠Sustainable Manure and Compost Application: Garden and Micro Farm Guidelines ⢠Sustainable Manure and Compost Application: Manure Application Calculation Excel Workbook Although adding organic matter is traditionally the most effective way to enhance soil water-holding capacity, several commercial products in the market also have the potential to increase soil water-holding capacity. In this fact sheet, we will discuss the properties and characteristics of those commercially available products and recommended application rates. We will also explore some limitations of using these products. Application 1