Response of canola yields from marginal lands managed with tillage practices

In recent years the discourse regarding the effective use of dwindling agricultural spaces for food, fiber, or fuel production has grown and it is becoming increasingly important to manage non-agricultural or marginal spaces that make them suitable for crop production. Highly eroded, highly compacted, low nutrient soils, similar to those found along highway rights-of-way (ROWs) offer unique field characteristics that can be used to study crop production potentials and land use decisions. This work evaluated the feasibility of maintaining a canola crop production system on the non-agricultural soils of highway ROWs across the humid subtropical climate within North Carolina, USA as a bioenergy feedstock for renewable fuels. Specific objectives included examination of (1) three different North Carolina geoclimatic conditions and (2) three levels of tillage (conventional (CT), minimum (MT), and no-till (NT)) on canola (Brassica napus L.) grain yields cultivated on ROW soils. Field experiments were conducted for two growing seasons in the Inner Coastal Plain, Piedmont, and Mountains regions and assessed main and interaction effects among tillage, site, and year of cultivation on crop productivity. After season 1, CT produced the highest average yield (1.24 Mg ha−1) followed by MT (0.93 Mg ha−1) and NT (0.86 Mg ha−1), respectively. In the second year, the comparative intensity of productive effects from CT was lower, and plots cultivated under MT resulted in the highest average yields (2.70 Mg ha−1), followed by CT (2.69 Mg ha−1) and NT (1.96 Mg ha−1), respectively. Yields observed were comparable to regional canola grain yields, and no significant difference was observed between yields under CT versus MT. These findings suggest that reduced levels of tillage on ROW soils in North Carolina hold the potential to produce yields comparable to those realized in traditional agricultural soils, and targeted tillage practices can support improved suitability of marginal crop production spaces.