Publication Date

Spring 2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Studies

Advisor

Rachel O'Malley

Keywords

agriculture, caneberries, nitrogen, runoff, stormwater, water

Subject Areas

Environmental studies; Agriculture; Water resources management

Abstract

With a 700% rise in global fertilizer use in the last 50 years, agricultural lands are a significant source of nitrogen and phosphorus pollution in aquatic ecosystems worldwide. Record high levels of nitrate-contaminated runoff from agricultural sources in California's Central Coast are affecting drinking water supplies in the Pajaro Valley and increasingly threatening the ecological health of the Monterey Bay. Bands of vegetation strategically planted to control runoff and soil erosion, or vegetative filter strips (VFS), are used in urban landscapes and at some farm peripheries. On-farm vegetative diversity has been promoted for its contribution to biodiversity and pest control. The efficacy of in-row VFS for nutrient removal, however, has never before been explored in caneberries, the fastest-growing agricultural commodity in Central California. This on-farm study experimentally tested the ability of three different types of common and native VFS planted between the rows to reduce nitrogen runoff in California caneberry fields: California field sedge (Carex praegracilis), creeping wild rye (Leymus triticoides), and wild mustard (Brassica juncea). Overall, nitrates in runoff decreased significantly with greater VFS cover. Of the three species tested, L. triticoides grew fastest, but B. juncea yielded the greatest cover by the end of the rainy season. VFS were shown to be a cost-effective tool that growers can use in California caneberries to decrease nitrate runoff while inherently promoting on-farm biodiversity.

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