The Use of Tree Mulch to Increase Native Grassland Pasture Fertility

Three control plots along with four test plots have been constructed to monitor a change in soil carbon caused by the application of Eastern Redcedar chips to native grassland pasture. Soil carbon data has been collected. Once three years of data have been collected, statistical analysis will be conducted on the data to determine the trend in soil carbon levels.

Introduction:

The Oak View Park (a.k.a. Oak View Beef) ranch has an abundance of Eastern Redcedar trees at various stages of growth. Instead of continuing the practice of burning piles of cut cedar trees, we speculated that some good could come from the utilization of chipped cedar trees.

The soils on this ranch consist mainly of various types of sand (we’re located on the eastern edge of the Nebraska sandhills region) with an aerobic zone appearing to extend up to three feet deep (the depth to which a fence post will rot). Historically, many of the land parcels on the ranch suitable for farming (prior to cedar tree infestation) have been tilled, with active tillage ending in the late 1950s. Once we took ownership of the ranch initial soil tests indicated that the soils have less than 1% humus, are deficient in calcium and lack sufficient phosphorus levels. The soils have been mined out with traditional farming methods. Ironically, subsoil testing down three-to-four feet deep shows excess quantities of calcium and phosphorus, registering 3691 ppm calcium and 126 ppm phosphorus. This lack of upper soil fertility manifests itself with Big Bluestem, Switchgrass and Indian Grass commonly growing as bunch grasses with no seed heads. Exposed bare ground is common among the plants. A cross-section of the soil in the barren spaces lacks a well-defined A-horizon.

Bare ground heats up considerably faster than soil protected with a layer of thatch. A thatch layer also helps conserve soil moisture by protecting the soil from desiccation. The longer a soil can be kept cool with adequate moisture the longer the microbial life can remain active. It’s the soil’s microbial life that recycles the minerals in the soil and creates humus (soil carbon).

An increase in humus has the capability to store more moisture. More humus also increases the soil’s cation (CEC) and anion (AEC) exchange capacities. The higher the CEC/AEC the more nutrients the soil can hold and eventually make available to the plants, thus an increase in soil fertility. Of course, if the nutrients are not present in the soil, the nutrients will need to be added by some other means to fill the AEC/AEC reservoir.