Effects of compost on onion quality, yield, and thrips infestation

Authors: Showler, Allan

Submitted to: Environmental Systems Research Institute Users Conference Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2022
Publication Date: 12/5/2022
Citation: Showler, A. 2022. Effects of compost on onion quality, yield, and thrips infestation. Environmental Systems Research Institute Users Conference Proceedings. https://doi.org/10.1186/s40068-022-00268-2.
DOI: https://doi.org/10.1186/s40068-022-00268-2

Interpretive Summary: Although onion production has been enhanced by the addition of organic matter to soil, other reports have indicated no effect. In this study, onion field plots were treated with conventional fertilizer, composted sugar mill ash and vegetative yard waste, or both in combination. Measurements during two consecutive growing seasons in the Lower Rio Grande Valley of Texas were recorded on soil nutrients, nutrients in onion leaf tissue, leaf length, bulb yields in terms of numbers and weights in different size classes, and biochemical quality. Our findings demonstrate that the compost enriched soil fertility, particularly P, K, and Zn, and percentage N in the onion leaf tissue was increased to the same extent as plants that received fertilizer, and leaves grew the same length as in plots with fertilizer. At harvest, small cull bulbs were consistently more prevalent in the control, and although compost had a positive influence on numbers and weights of marketable bulbs, fertilizer provided the highest yields during the first growing season. During the second season, however, marketable bulbs in composted plots were as abundant as in the plots receiving fertilizer. The compost was useful for increasing marketable onion yield, and that effects improve as the compost decomposes over several growing seasons.

Technical Abstract: Although onion, Allium cepa L., production has been enhanced by the addition of organic matter to soil, other reports indicated no effect. In this study, onion plots (var. Sweet Sunrise) were treated with conventional fertilizer, composted sugar mill ash and vegetative yard waste, or both in combination. Measurements over two consecutive growing seasons in the Lower Rio Grande Valley of Texas were recorded on soil nutrients, nutrients in onion leaf tissue, leaf length, bulb yields in terms of numbers and weights in different size classes, and biochemical quality. Our findings demonstrate that the compost enriched soil fertility, particularly P, K, and Zn, and percentage N in the onion leaf tissue was increased to the same extent as plants that received fertilizer, and leaves grew as long as in plots with fertilizer. At harvest, small cull bulbs were consistently more prevalent in the control, and although compost had a positive influence on numbers and weights of marketable bulbs, fertilizer provided the highest yields during the first growing season. During the second season, however, marketable bulbs in composted plots were as abundant as in the plots receiving fertilizer. We conclude that the compost was useful for increasing marketable onion yield, and that effects improve as the compost decomposes over several growing seasons.