The long-term vegetable production experiment: plant growth and soil fertility comparisons between fertilizer and compost-amended soils

By P.R. Warman

Department of Environmental Sciences, Nova Scotia Agricultural College, Truro, N. S., Canada
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Abstract
A study of compost versus conventionally-fertilized vegetable plots was conducted for 12 years in a sandy loam soil near Truro, Nova Scotia. The fertility treatments have been applied annually to six rotation plots planted with six to eight different vegetable crops. The composts consist of animal manure, food waste, yard waste and straw or racetrack manure bedding. This paper investigated the last year of the study (2001), which examined levels of nutrients in soil, leaf tissue, the edible portion of the plant, and crop yields.

The fresh weight yields from the six plots showed that the compost treatment resulted in numerically, but not significantly, higher yields for the carrots, peppers, onions and tomatoes, and significantly higher yields for green and yellow beans. Cauliflower and Brussels sprouts yields, however, were higher in the fertilizer-amended plot. Soils with compost had higher pH, CEC, C, N and Mehlich-3 extractable levels of P, Ca, Mg, Mn, Zn and B compared with the fertilized plots.

However, the increased nutrients in the compost-amended soil did not increase the nutrients in the leaf tissue or the edible portion of the plant. Of the 16 elements tested, only P and K were higher in the fertilizer-amended plant leaf tissue, while levels of P were significantly higher in the edible portion of the plant.

This study demonstrated that the long-term use of compost can produce similar yields and elemental analysis for most crops in compost-amended and conventionally-fertilized soils.