Soil health indicators after 21 yr of no-tillage in South Coastal British Columbia
Thomas, B.W., Hunt, D., Bittman, S., Hannam, K.D., Messiga, A.J., Haak, D., Sharifi, M., Hao, X. (2019). Soil health indicators after 21 yr of no-tillage in South Coastal British Columbia. Canadian Journal of Soil Science, [online] 99(2), 222-225. http://dx.doi.org/10.1139/cjss-2018-0146
Plain language summary
The lower Fraser Valley is arguably the most intensively cropped region in Canada. In the long term, which is the reality for multiple generation farmers, intensive cropping systems may degrade soil health. However, there has been limited efforts to measure and monitor indicators of soil health in the lower Fraser Valley. To improve understanding of how long-term intensive cropping practices may impact soil health in the lower Fraser Valley, a suite of soil health indicators were measured after 21 years of continuous silage corn under conventional tillage or no tillage. Long-term conventional tillage negatively impacted two important physical soil health indicators, wet aggregate stability and available water capacity, suggesting that adoption of no-till could improve resistance to erosion and water-use efficiency. We also found that the amount of active carbon, which acts as an energy source for the microorganisms that live in the soil, was greater with no-till than conventional tillage. Collectively, this provides evidence that no-till improved soil health, not only from a crop production standpoint, but also as a habitat. It is important to remember, the context of this long-term field trial may be seen as an intensively managed system, or a worst case scenario, since there is corn monoculture, little residue, no manure, and no winter cover crop. Farmers in the lower Fraser Valley use manure and winter cover crops, which helps to reduce the impact of tillage operations over long periods of time, consistent with the principles of sustainable agriculture.
The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.