Abstract Water contamination and soil losses in the agricultural area associated with potato production in New Brunswick, Canada have been recognized as an environmental issue for past several decades. With a well-instrumented and maintained watershed (The Black Brookwatershed (BBW)), the impacts of potato cultivation and land management practices on stream water yield and sediment load during 1992-2008 were evaluated. During the study period, yearly cumulative precipitation varied from 827.5 mm to 1183.4 mm with an average of 1057.5 mm. Monthly distribution was generally even around months except for July where about 10% of annual precipitation fell. Standardized precipitation index (SPI) varied from -2.3 to 1.15, indicating very drought to moderate wet pattern. Annual discharge varied from 351.7 mm to 897.2 mm with an average of 606.1 mm. The discharge amount accounted for 35-79% (average 57%) of precipitation in the watershed. The discharge in April accounted for 33% annual discharge. Erosivity varied greatly from 641 MJ mm ha-1 hr-1 to 2803 MJ mm ha-1 hr-1 (average of 1520 MJ mm ha-1 hr-1) with a slight increasing trend over years. The most erosive months were June, July, and August and the total erosivity from these months accounted for 57% of annual erosivity. Soil loss displayed a large annual variation, ranging from 5.58 t ha-1 yr-1 to 0.88 t ha-1 yr-1 with an average 3.04 t ha-1 yr-1. Monthly soil loss varied from 1.37 t ha-1 yr-1 in April to 0.02 t ha-1 yr-1 in September with an average of 0.29 t ha-1 yr-1. The soil loss in April accounted for 39.7% of annual soil loss, followed by March (12.8%) and May (9%). Totally, 61.5% of annual soil loss occurred in these three months. In a given year, various hydrological parameters generally followed similar patterns to the multiple-year summary trends. Suspended sediment concentrations were significantly correlated to flow velocity at 99% confident limit with a coefficient of correlation of 0.63 or 40 % of the variation in sediment concentration can be explained by flow velocity. Daily mean flow velocity ranged from 0.12 m3 sec-1 to 1.55 m3 sec-1 with an average of 0.25 m3 sec-1, resulting in an annual discharge of 3.78 to 48.88 million m3of water from the entire watershed. Because of the significant sediment loading, the water of the Black Brook was unsuitable for drinking and supporting aquatic life around the year and suitable for recreational use only in 12% time of the year. Various beneficial management practices (in particular terrace and grassed waterway) adopted in the watershed greatly helped for reducing soil loss at the watershed level, which has statistically been verified from this study. The soil loss showed a statistically significant linear reduction (p < 0.001) with the increasing accumulated areas protected by terraces and grassed waterways with r2value 0.65.