Environmental effects of growing woody crops on agricultural land: First year effects on erosion, and water quality

Abstract

The objective of this study is to assess the effects of converting row crop agricultural land to short-rotation, woody-crops (SRWC) on erosion, surface water quantity and quality, and groundwater quality. Three physiographic regions in the Southeast, of varying soils, slope, and erodibility, were used. Replicate plots were equipped with a flume and four pan lysimeters so that event sampling of runoff and groundwater could be conducted. Cropping treatments had little effect on the runoff volumes collected; however, sediment produced by the various treatments was significantly influenced by crop. At all three sites, spring and fall generally had the highest Sediment losses. The highest absolute losses of sediment occurred at the Mississippi Delta Site. Conventional tilled cotton (Gossypium hirsutum L.) lost 16.2 Mg ha-1, compared to 2.3 Mg ha-1 for cottonwood (Populus deltoides Marsh) over 14 months. While sediment losses at a loess-belt site in west Tennessee were three-fold higher under no-till corn (Zea maize L.). than sycamore (Platinus occidentalis L), total sediment loss was less than 1 Mg ha-1 for both treatments. At the north Alabama site, no-till corn and sweetgum (Liquidambar styraciflua L.) with a rescue (Fescue elitor L.) Cover crop did not differ with respect to erosion. However, sediment losses under sweetgum without a cover crop were significantly higher, exceeding 5 Mg ha-1. Nutrient losses of N and P in both runoff and lysimeters were primarily influenced bY spring mineral fertilizer applications Spring and early summer lysimeter nitrate values exceeded EPA guideline for drinking water in the row crop treatments.