On-site use of plant litter and yard waste as mulch in gardening and landscaping systems

Abstract

Plant litter, such as fallen leaves, branch trimmings, and other yard waste, plays important roles in both natural and man-made ecosystems. However, due to common aesthetic perceptions, land-owners or managers of many residential gardening and municipal landscaping systems consider these organic residues a burden, and therefore, clear them from the ground and dispose of them off-site. The removal of these organic resources increases the system's environmental footprint, decreases its sustainability, and negates the provision of important ecosystem services. At the same time, retaining these organic materials on-site could provide the system with substantial benefits. The most obvious effect is the ground surface shading, which decreases direct solar radiation to the soil, lowers soil temperature, lessens evaporation rates, decreases risk of soil salinization, and improves water-use efficiency. Ground surface mulching likewise prevents the raindrop splash impact, negates the formation of sealed mechanical crusts, improves water infiltrability, and reduces water runoff and soil erosion. Another benefit is the on-site decomposition of organic materials, which improves soil quality by elevating organic carbon concentration and contributing to nutrient cycling. Vegetation patches in such systems encompass "engineered fertility islands", which can be defined as highly productive, healthy, and functioning habitats. Further, over time, these systems require less maintenance. This management practice is crucial for tree- or shrub-dominated gardening and landscaping systems in drylands, where water availability is the major limiting factor of vegetation growth. However, global climate change, in which extended parts of the world experience increasing temperatures and decreasing precipitation rates, makes this practice relevant for other climatic regions as well.