Depth to compact subsoil effects on soil properties and barley–potato yields on a loamy soil in New Brunswick

An experiment was established to investigate the implications of thickness of soil over compact subsoil on plow layer soil thermal and water regimes and ultimately the yield of potato (Solanum tuberosum L.) and barley (Hordeum vulgare L.). Three depths were considered, 24 cm (shallow), 36 cm (medium) and 60 cm (deep). Results on soil temperature impacts were inconclusive. The shallow treatment water content was most greatly affected by precipitation and had the greatest potential to become saturated then drying out more than the other treatments. The deep treatment did not improve soil temperature and water regimes enough to increase crop yield. The medium depth, which most closely approximated existing local solum development, proved superior to the shallow treatment in terms of crop yield and reduced soil moisture variation, while the deep treatment did not warrant the effort required to create under field conditions. Barley and potato yields from the medium depth were greatest with 20% (significant) and 8% (not significant) more yield, respectively, than from the shallow treatment. The eroded soil profiles common to the New Brunswick potato belt exacerbate soil erosion since an eroded soil has less volume to accept water from a rainfall event, making the soil more prone to erosion, especially if it is true that our weather is changing, with the amplitude of weather shifts becoming greater. Incorporation of subsoil materials into the plow layer of eroded soils due to soil loss may result in further reduction in crop yield.