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3.Quality Comparison of Carrots (Daucus carota L.), Fertilized Organically or Chemically, with Differences in Growth Eliminated

Shoji Nakagawa1, Yuriko Tamura1, Hideharu Yamamoto2, Kiyoko Yoshida3, Tomotaka Yoshimoto1(1 Institute for Agro-Microbiology 2 Japanese Federation of MOA Nature Farming Branch Cooperatives 3 Kagawa Nutr. Univ.)

Over a period of three years from 1997 through 1999, carrots were grown with application of chemical and organic fertilizers in experimental fields for comparison of quality. High-analysis compound fertilizer and coated high-analysis compound fertilizer were applied as chemical fertilizer. Fermented rice bran and alfalfa tops were applied as organic fertilizer. The carrot qualities measured were hardness (hardness tester), color (colorimeter), sugar content, carotene content, mineral content and sensory appeal. In order to remove the difference in the amount of growth among carrots in each treatment, fertilization rates were adjusted to obtain the same range of growth, and in addition, ANCOVA was partially applied to root weight as a covariate when appropriate.

1) The carrots grown with the organic fertilizers tended to show lower hardness, color intensity, sugar content, carotene content, Cu content, and strength of smell and to score lower on the comprehensive sensory evaluation, while having higher Na, P and Mg content than those grown with chemical fertilizers.

2) Since the frequency of appearance or the tendency of differences in quality of carrots grown with different fertilizers differ slightly with varieties of carrot and cultivation years, it is suggested that cultivation conditions somewhat affect the result of comparison of quality.

3) There results indicate that the application of organic fertilizers does not always improve the quality of carrot.

Keywords: carrot, organic fertilizer, quality, chemical fertilizer