Fluidized Bed Material Applied at Disposal Levels: Effects on an Apple Orchard

Abstract

AbstractAtmospheric fluidized‐bed combustion represents an economical technology for the burning of high S fossil fuel. The combustion residue is a dry, alkaline material resulting from the burning of coal (or other fuel source) and limestone. Although the residue has been assessed as a limestone substitute, the current study examines the potential for disposing of relatively large quantities. Fluidized bed material (FBM) was applied at two rates to the surface area within the rows of an established apple (Malus domestica Borkh.) orchard containing four tree types. The rates were either 9.2 kg/m2 (low rate), 36 kg/m2 (high rate), or untreated control. The tree types used were ‘Spuree Rome’ on M9, ‘Redchief Delicious’ on M9 or M9/MM106, and ‘Sturdeespur Delicious’ on M9. Cumulative yields (kg/tree) were enhanced on three of four tree types over a period of 6 yr. A 15% reduction in yield was noted for Redchief Delicious on M9/MM106 stocks at the high FBM rate. No nutritional related problems were noted for this or any other of the tree types used. Part of the yield reduction noted was due to fruit size differences and/or differential sensitivity of this interstock/rootstock combination to the altered soil chemical properties. Generally, amended soil pH increased to about 7.0 for either rate, and electrical conductivity increased five fold at the high rate of FBM addition. Agricultural utilization of large volumes (up to 112 Mg/ha) of FBM, compared to past research where FBM was used as a lime substitute (2–6 mg/ha), appears to be a feasible alternative. However, rootstock selection for apple may need to consider the resultant changes in soil chemical status from FBM additions.