Effects of Hay Mulch on Soil Properties and Potato Tuber Yield under Irrigation and Nonirrigation in New Brunswick, Canada

Abstract

Organic mulching and irrigation are considered to be important soil conservation and agricultural practices. However, the effectiveness of these practices on soil properties and potato production in the relatively cool, moist maritime region of Canada has not yet been well studied. In the growing seasons of 2000–2003, a field experiment was conducted at the Potato Research Centre, Agriculture and Agri-Food Canada, Fredericton, New Brunswick, to assess the benefits of hay mulching on a loamy sand soil under potato production. Treatments consisted of four levels of hay mulching: 0, 2.25, 4.5, and 9.0 Mg ha-1 with four replicates under irrigation or nonirrigation. Results showed that hay mulching could help conserve soil moisture in nonirrigation treatments with an increase of mean soil moisture content by 5.7 to 9.5% under 2.25 to 9.0 Mg ha-1 of hay mulch relative to a control. The greatest conservation effect on soil water in our region would be achieved with a mulch rate of 5.6 Mg ha-1. Under irrigation, mulching slightly increased soil temperature. Without irrigation, soil temperature was affected both positively and negatively by mulching, depending on time of day and quantity of mulch applied. During periods of warmer weather, mulching reduced maximum soil temperature during daytime but increased minimum soil temperature during nighttime. While the magnitude of soil temperature change was slight, it varied linearly with mulch quantity. During periods of cold weather, mulching generally increased soil temperature. The soil organic carbon content in the year following mulching increased proportionally with the amount of mulch applied in the nonirrigated treatments. Thus, thicker mulching treatments resulted in a greater increase in soil organic matter accumulation. Irrigation was found to potentially induce organic matter loss for the lower mulching treatment (2.25 Mg ha-1) and control. No significant effects of hay mulching on total potato tuber yield under irrigation were found, but tuber yield under nonirrigation increased linearly with the amount of mulch applied.