Chemical and physical properties of soil amended with pecan wood chips

The pruning wood of pecan [Carya illinoinensis (Wangenh.) K. Koch] is often burned. Chipping and soil incorporation of pruning wood is becoming more popular as a result of environmental constraints on burning. The objective of our research was to determine how pecan wood incorporation into soil affects the soil chemical and physical properties. Pecan wood chips were incorporated into a silty clay soil at rates of 0, 4484, 8968, 13,452, and 17,936 kg.ha(-1) in Summer 2002, 2003, and 2004. Some plots received nitrogen at a rate of 0, 15.2, 30.5, 45.7, and 61.0 kg.ha(-1) to adjust the C : N ratio of trimmings to 30 : 1. Ammonium sulfate, as a nitrogen source to balance the C : N ratio of pecan wood chips, reduced soil pH. However, the wood chip amendments alone did not reduce soil pH. Soil salinity (as determined by electrical conductivity) and bulk density were unaffected by wood chip incorporation regardless of application rate or number of applications. Incorporation of pecan chips had little effect on soil moisture content, but the soil had an inherently high waterholding capacity. Pecan wood chip incorporation significantly increased soil organic matter content and aggregate stability, particularly at the higher application rates and with repeated amendment. The incorporation of pecan pruning wood into the soil appears to improve soil tilth and aggregation while providing growers with an environmentally acceptable means of disposal.