Low-volume irrigation systems influence Pratylenchus penetrans populations, root colonization by arbuscular mycorrhizal fungi, and replant establishment of sweet cherry
Watson, T.T., Nelson, L.M., Neilsen, D., Neilsen, G.H., Forge, T.A. (2018). Low-volume irrigation systems influence Pratylenchus penetrans populations, root colonization by arbuscular mycorrhizal fungi, and replant establishment of sweet cherry. Scientia Horticulturae, [online] 239 50-56. http://dx.doi.org/10.1016/j.scienta.2018.05.013
Plain language summary
Irrigation is necessary for tree fruit production in the Okanagan Valley of British Columbia, but newly replanted trees with limited root systems are especially sensitive to inadequate irrigation. A collection of root pathogens including plant-parasitic nematodes are usually present in soil where fruit trees grew previously. These organisms severely inhibit early root growth of replanted trees, exacerbating the effects of inadequate irrigation. The objective of our research was to determine how drip and micro-sprinkler irrigation compare with respect to their effects on the activity of lesion nematodes and early root growth of cherry trees replanted into old orchard soil. We found that drip irrigation resulted in smaller populations of lesion nematodes, and greater root growth, overall tree growth and fruit yield than micro-sprinkler irrigation through the first four years after replanting. Roots of drip irrigated trees also were more heavily colonized by beneficial symbiotic arbuscular mycorrhizal fungi, which likely contributed to reduced nematode infection and overall healthier root systems. Overall, the results point to drip irrigation as an additional component of a package of sustainable practices that can be adopted to optimize early growth, productivity and economic returns of replanted orchards.
A four-year study was conducted to establish the effects of drip and microsprinkler irrigation systems on populations of Pratylenchus penetrans, early plant growth, and fruit yield of sweet cherry trees planted into soil previously used for apple production. The effects of irrigation type on root colonization by arbuscular mycorrhizal fungi, the abundance of soil microbial antagonists, soil biological suppressiveness, plant nutrition, and soil water content were also evaluated. Trees that received drip irrigation had larger trunk diameters than trees irrigated with microsprinklers throughout the first four years of orchard establishment, with greater total fruit yield also observed with drip irrigation in the fourth growing season. Populations of P. penetrans in soil and roots were smaller under drip irrigation than microsprinkler. Trees irrigated using drip emitters had higher per cent root colonization by arbuscular mycorrhizal fungi than those irrigated by microsprinklers, and had a greater density of fine roots in soil. Drip irrigation also increased soil volumetric water content in the root zone, with soil moisture content often approaching or exceeding field water-holding capacity relative to that of microsprinklers. Overall, drip irrigation shows potential as a component of an integrated pest management strategy for reducing the effect of P. penetrans on newly planted sweet cherry.