Gayla leJeune and Shana Kunefke
ABSTRACT
The pH level on three compost piles was tested. pH levels between seven
and eight were obtained on two of the three samples and a pH level of approximately
six was obtained on the third sample. Information on the management of
composting systems with respect to factors other than pH was researched
and summarized.
INTRODUCTION
The pH levels from samples of compost was sought as it was:
1. a test which was performable by the authors
2. a readily obtainable condition of the soil and
3. an indicator of other soil properties.
The composting systems studied were generally "unmanaged" in terms of proper preparation for application to plant-soil systems. However, in each case, the compost piles were used as "storage" (one of the benefits of composting, according to Brady and Weil (1999)) for food wastes and yard clippings that would otherwise increase the bulk of household garbage. An interest in recycling and eliminating the odors that result from food decomposition in the home wastebasket was motivation for the starting of a compost pile.
Composting has been practiced for many years, but gained considerable popularity at the turn of the last decade when over one-third of the United States banned the collection of yard clippings (Glen 1999). Although households may use composting as a means of recycling on a small scale, the practice has become an important nationwide industry.
Many materials are used in industrial composting, ranging from the more "conventional" agricultural, municipal, and animal farm wastes to the "newer" additives like restaurant wastes, wood, and surplus phone books. While acting as an important means of recycling, industrial composting produces a product that can be used to enhance soil conditions relative to plant growth and soil production.
According to Sikora and Enkiri, "composting of organic residues results
in a final product that can be stored, handled easily, and applied to land
uniformly for beneficial use as a low-analysis fertilizer and soil conditioner"
and compost can add nutrients that N P K fertilizers fail to add (1999).
MATERIAL AND METHODS
Samples from three "unmanaged" compost piles were tested for pH levels. All composting systems were composed of yard and garden clippings and common household food wastes like eggshells, coffee grounds, and unconsumed "table scraps". In general, the addition of oils, fats, and meat products was avoided.
The three compost piles were located in the following areas: Denham Springs, Port Barre, and Eunice. The composition of the "Eunice" composting system varies from the other two in that it is located in a pine woods area and contains a large percentage of pine needles.
A commercially available gardener's soil pH testing kit was used on
all three samples and tests were conducted per instructions.
RESULTS AND DISCUSSION
The pH levels on the "Denham Springs" and "Port Barre" locations were approximately the same, both of them mildly alkaline, between the colors indicating pH levels of seven or eight. The "Eunice" compost pile was more acidic than the other two, its test color indicating a pH level of approximately six.
Although there was some difference between the pH levels of the three compost systems, the levels were within the normal range for most soils (i.e., 3.5-8.5). Generally, the addition of pine needles and/or pinecones to a composting system is discouraged because of the affect that this additive can have on the acidity of the compost (Novara 1997). For this reason, it was expected that the "Eunice" compost pile would have a slightly more acidic pH level than the other two samples. Another commonly used pH-altering additive is lime material.
Because a normal pH level in soils can indicate certain soil properties such as microorganism rate of activity (which results in the improvement of other soil conditions that are conducive to plant growth (Gaston 1999)), the finished compost from the three compost piles could be used, at the very least, as a non-specific application to a plant-soil system.
However, in preparing a high-quality finished compost, other factors
must be considered. In addition to the measures already taken (i.e., starting
materials, beneficial and non-beneficial additives) by the three "composters"
in this study, Brady and Weil suggest aeration and moisture levels be monitored
to ensure sufficient amounts of microbial activity (1999). In addition
to these controls, sources of carbon (e.g., leaves, straw, and hay) and
nitrogen (e.g., manure, green plant waste, and urine) are recommended (Glaese
1986).
WORKS CITED
Brady, Nyle C., and R. R. Weil. 1999. The Nature and Properties of Soils. (Upper Saddle River, NJ: Prentice-Hall).
Gaston, Lewis. 1999. Agronomy 2051 Lab Manual. (Baton Rouge: Louisiana State University).
Glaese, Susan. 1986. "Making and Using Compost," Mother Earth News, 101: 46-51.
Glen, Jim. 1999. "The State of Garbage in America," Biocycle, April: 64.
Novara, Joseph K. 1997. "What's in the Heap?" Mother Earth News, 160: 34-36.
Sikora L. J., and N. K. Enkiri. 1999. "Growth of Tall Fescue in Compost/Fertilizer Blends," Soil Science 164: 62-69.