Articles
RESULTS OF THE LONG-TERM VEGETABLE CROP PRODUCTION TRIALS: CONVENTIONAL VS COMPOST-AMENDED SOILS
Compost and fertilizer applications have been based on the results of soil samples and soil test recommendations assuming 50% or 100% availability of the total N in the mature composts and fertilizers.
The composts were made using a combination of animal manures, food waste or grass clippings and straw or racetrack bedding.
Marketable yields have been taken annually while soils have been sampled for pH, organic matter and Mehlich-3 extractable nutrients since 1994.
Since 1993, when the crop yields from the paired plots were equal, yields from the compost-amended plots were higher in 1994, about equal in 1995 (except for onions and tomatoes) and mixed in response to amendments in 1996. The most recent Mehlich-3 extractable soil tests (October 1996) indicate that conventionally-fertilized soils are generally higher in P and K but lower than compost-fertilized soils in C, Ca, Mg, Mn, Cu and Zn.
Mineralization of recently added and previously applied compost strongly influenced plant response in a particular crop year, especially for high nutrient demanding crops.
Seasonal variation in soil moisture and temperature seem to have a greater influence on plant production than the source and amount of compost applied.
The author intends to continue cropping in order to evaluate crop production and the differences in the type of soil organic matter developed in these contrasting fertility plots.