Because, sand, stone and gravel are under prime farmland, it contributes to its drainage, allowing crops to avoid waterlogging. Pits and quarries reduce available prime farmland, and as a result interfere with food sustainability in Ontario. Despite claims that farmland can be restored, there is loss of fertility during the time it is in berms and loss of surface area due to the steep sides of pits and quarries. Even when extraction removes features like alvars, eskers or moraines, there is a loss of surface area. In many cases, rehabilitation of below-water pits leaves water features, a net loss of farmland and tax revenues for rural municipalities.
The Ontario Farmland Trust estimates a daily loss of farmland in the order of 175 acres to sprawl and aggregate. The National Farmers union has concerns too about temporary loss of lands been permanent loss of land quality or total area. Though slimmer than urban sprawl, the loss to pits and quarries is significant to future food security. The Ontario Federation of Agriculture has asked that Agricultural Impact Assessments be required before licenses are issued and that rehabilitation occur swiftly after interim use. The prospect of rehabilitation should not, they and others suggest, be an argument in favour of aggregate extraction in prime farmland areas, in part because it is so seldom achieved.
Dust settling on adjacent farm properties can reduce the photosynthesis of plants, their production and marketability. Where settling on livestock, it like noise can have similar health effects as on humans – consequences for lung, heart and brain. OMAFRA states the following: Particulate matter such as cement dust, magnesium-lime dust and carbon soot deposited on vegetation can inhibit the normal respiration and photosynthesis mechanisms within the leaf. Cement dust may cause chlorosis and death of leaf tissue by the combination of a thick crust and alkaline toxicity produced in wet weather. The dust coating (Figure 5) also may affect the normal action of pesticides and other agricultural chemicals applied as sprays to foliage. In addition, accumulation of alkaline dusts in the soil can increase soil pH to levels adverse to crop growth. Conversely, where the water table has been lowered by aggregate extraction, crops may lack water from the soil or wells and not grow as well.
See also https://www.neptis.org/sites/default/files/smart_growth_issue_papers_agriculture/agriculture_nip1.pdf