Agriculture, Fisheries and Aquaculture - The Effects of Hay Mulching on Runoff, Erosion, Soil Properties and Potato Yield in Northwestern New Brunswick

Abstract: In 1995 a collaborative project between the New Brunswick Department of Agriculture, Fisheries and Aquaculture and Agriculture and Agri-Food Canada was established to test the effects of hay mulch on soil erosion in the New Brunswick potato belt where soil degradation has been severe. A comparison of runoff and erosion rates was made using 7 Wischmeier-type permanent erosion plots (10m x 30m) located in the Drummond area, 5 km east of Grand Falls. Various rates of mulch application were evaluated at two slope gradients from harvest 1995 until harvest 1996. Application rates at the 11 % slope were 0, 2.25, 4.5 and 9 T ha-1; and 0, 2.25, and 4.5 T ha-1 at the 8 % slope. At the 11 % slope runoff decreased as application rate increased. However, this relationship did not hold at the 8 % slope for the winter runoff events. Hay mulch at rates as low as 2.25 T ha-1 reduced soil loss by 70 to 80 % for the 8 and 11 % slopes, respectively. There were no significant treatment differences in total or marketable yield for the 0, 2.25 and 4.5 T ha-1 treatments at both slopes. The 9 T ha-1 treatment, however, resulted in significantly lower yield than all other treatments at the 11 % slope. As well, marketable yield was significantly less at the 11 % slope than at 8 %. By increasing infiltration and decreasing runoff, the incorporated hay mulch resulted in generally higher (2-5 %) soil moisture levels over the growing season. Soil temperature levels at 20 cm may be reduced by mulching, however, not significantly so to reduce yield. More research is required to verify these tentative results.

¹Land Resources Branch, NBDARD, Fredericton, NB E3B 5H1
²Agriculture and Agri-Food Canada, Fredericton, NB E3B 9H8
³Regional Office, NBDARD, Grand Falls, NB E3Z 1G1