Precision application of organic amendments for improved soil quality in replant orchards

During apple orchard renewal, Apple Replant Disease (ARD) and soil degradation can lead to inconsistent infill vigor and uneven fruit production. Brassica seed meal is an effective organic amendment for suppressing ARD and improving soil fertility in new plantings, but it is expensive and not necessary for orchard areas that do not express ARD. We propose to investigate spatial predictors of ARD and whether site-specific application of organic soil amendments can be used to suppress ARD, improve general soil health, and promote uniform tree growth. The proposal addresses two priority areas: “Biologically-intensive and organic approaches to building soil quality” and “Novel approaches to weed, disease, pest, and/or fertility management that transcend traditional conventional or organic approaches” by combining precision agriculture principles with organic approaches to improve soil quality and fruit production. We will intensively map soil fertility and texture for an organic orchard block hosting new plantings, apply uniform vs. targeted rates of organic amendments, and monitor soil microbial and fertility response in addition to tree root and canopy development. This study will contribute to our understanding of the spatial variability of ARD, and will provide foundational knowledge for developing precision agricultural practices in organic orchards to promote soil quality and fruit production.