Submitted to: European & Mediterranean Plant Protection Organization
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/1/2005
Publication Date: 7/1/2005
Citation: Holtz, B.A., Mckenry, M.V., Caesar, T. 2005. Wood chipping and its effect on soil and petiole nutrients, soil aggregation, water infiltration, nematodes and basidiomycetes populations. Mediterranean Options. 63:247-254. Interpretive Summary: The wood chipping or shredding of almond prunings could provide an alternative to burning that can add valuable organic matter to soils from San Joaquin Valley from California typically low in organic matter. The effects of wood chips on soil and petiole nutrients, soil aggregation, water infiltration, and nematode and basidiomycete populations was initiated in an experiment where soil was mixed with or without wood chips and placed in containers, each with an almond tree. The addition of wood chipped almond prunings to soils appear to be enhancing soil nutrients levels, basidiomycete wood rotting and soil aggregating fungi, and free-living nematode populations while providing almonds growers with a more sustainable method of brush removal.
Technical Abstract: The wood chipping of almond prunings in California, instead of burning, can reduce air pollution and return organic matter to soils. The success of wood chipping depends on whether the chips do not deplete critical nutrients necessary for tree growth. An experiment was established where soil was mixed with or without wood chips and placed in containers, each with an almond tree. There were more free living nematodes in the chipped soils when compared to non-chipped soils. More basidiomycetes were counted in wood chipped soils and detected in higher levels with ELISA. Larger soil aggregates were found in wood chipped soils. Undisturbed wood chipped soils had more soil aggregates than disturbed soils. After the first year trees growing with wood chips had less shoot growth, but by the second year trees with wood chips had more shoot growth. Soil analysis after two years showed higher levels of calcium, magnesium, sodium, boron, zinc, copper, carbon, phosphorus, potassium, ammonium, and % organic matter in wood chipped soils. There was less manganese, iron, and nitrate in the wood chipped soils and the pH was reduced. Tissue analysis was performed in leaf petioles. After the first year trees growing with wood chip[s had less nitrogen, zinc, and manganese, while phosphorus was still increased. Water infiltration was significantly greater in wood chipped soils all tree years.