ARS | Publication request: Timing of Pine Straw Harvests Affects Soil and Nutrient Losses

Submitted to: North American Agroforestry Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 12, 2008
Publication Date: May 31, 2009
Citation: Pote, D.H., Daniel, T.C. 2009. Timing of Pine Straw Harvests Affects Soil and Nutrient Losses. North American Agroforestry Conference.

Technical Abstract: Pine straw is a valuable landscape mulch because it conserves soil moisture, moderates soil temperature, inhibits weed growth, and protects the soil surface against erosion, while retaining a loose structure that allows water, air, and fertilizer to easily reach the soil surface. As a result, marketing pine straw has become a multi-million dollar industry, but the loss of those mulching benefits from pine forests can increase runoff, soil erosion and nutrient losses in watersheds where pine straw is harvested. It may be helpful to harvest pine straw relatively early in the fall so that needles dropping later in the season will provide some soil cover throughout the remainder of the year and minimize the environmental impacts of harvesting. To test this hypothesis, runoff plots were constructed in a 17-year-old pine stand with basal area of approximately 42 m2/ha and trees planted on a 3.0 m X 1.5 m spacing. Each plot (2 m X 1 m) had 4% slope, aluminum borders to isolate runoff, and a runoff collector. Pine straw was removed from all 16 plots in early October, and eight of them were immediately covered with screen mesh that allowed light and water to reach the plot surface, but prevented additional pine needle accumulation. Two months later, simulated rainfall was applied (50 mm/h) to produce 20 minutes of runoff from each of the 16 plots for treatment comparisons. Results showed that harvesting early in the fall decreased soil and nutrient losses in runoff by allowing additional straw to accumulate late in the season and help protect the soil surface.