Conservation tillage and cover crop management practices in potato production to improve soil health and profitability

In the humid climate of Prince Edward Island (PEI), Canada, fall moldboard plowing of forage before potato in a typical barley–forage–potato rotation and bare soil after potato harvest increased the risk of nitrate leaching and topsoil loss due to erosion. Data from two experimental studies in PEI during 2009–2016 and 2016–2017 were assessed to determine the effects of conservation tillage (including delaying fall plowing from fall to spring or using residue tillage equipment to replace moldboard plough) after forage and before potato and three winter cover crops after potato to evaluate economic returns and risk of returns trade‐offs for potato producers. Two cover crops after potato are used as cash crops (winter rye, winter wheat), and one is a winter-killed cover crop (spring barley). Factors related to conservation tillage such as soil erosion, nitrate leaching, planting date, effect on weeds, insects and diseases, potato harvest loss, and labor constraints were quantified. In a study with conservation tillage before potato, potato yields were the same for fall or spring plowing; however, residue tillage management produced higher potato yield compared to conventional fall moldboard plowing. Results showed residue tillage management and late fall plowing was preferred over spring plowing. Although spring tillage provides reductions in the risk of soil erosion and nitrate leaching, it also affects production risk and uncertainty. Therefore, farmers prefer plow forage as late as possible in the autumn or replace it with residue tillage equipment to reduce the risk of topsoil loss. In a study with winter cover crops after potato harvest, winter wheat grain yield ranged from 4.5 to 7.6 Mg ha−1, while that associated with winter rye ranged from 3.2 to 5.1 Mg ha−1. Therefore, winter cereal seeded after potato harvest can constitute a good source of revenue while mitigating the risk of soil erosion and reducing nitrate leaching in some cases.