Sweet Onion (Allium cepa L.) as Influenced by Organic Fertilization Rate: 2. Bulb Yield and Quality before and after Storage

Abstract

<jats:p>There is a growing interest in organic fertilizers because of increased demand for organic sweet onions and other vegetables. There are, however, limited studies on sweet onion bulb yield and quality in response to organic fertilization. The objective of this study was to evaluate the effects of organic fertilizer rate on sweet onion bulb yield and bulb quality before and after storage. Experiments were conducted at the Horticulture Farm, Tifton Campus, University of Georgia, in the Winters of 2012–13 and 2013–14. There were five organic fertilization treatments (organic fertilizer 3–2–3 equivalent to 0, 60, 120, 180, and 240 kg·ha<jats:sup>−1</jats:sup> N). Total and marketable yields and individual bulb weight increased quadratically with increasing organic fertilization rate and responses failed to reach a plateau. The fraction of extra-large bulb increased with increasing organic fertilization rate. Incidence of onion bolting was maximal at 60 kg·ha<jats:sup>−1</jats:sup> N and decreased with increasing organic fertilization rate. The percentage of bulb dry weight was highest in the unfertilized control and decreased with increasing organic fertilization rate. Organic fertilization rate had no consistent impact on bulb soluble solids content (SCC) and pungency (measured as pyruvate concentration) in the two seasons. Total antioxidant capacity (measured as gallic acid equivalents) values were among the lowest at 60 and 120 kg·ha<jats:sup>−1</jats:sup> N. In conclusion, onion bulb yields increased with increasing organic fertilization rate, whereas incidences of bulb diseases responded differently to N rate. Botrytis rot was the main cause of postharvest bulb decay in all organic fertilization rates.</jats:p>

Sweet Onion (Allium cepa L.) as Influenced by Organic Fertilization Rate: 1. Plant Growth, and Leaf and Bulb Mineral Composition

“…2A and B, optimal organic fertilization rates for biomass growth were 150 kg · ha -1 N (root) and 193 kg · ha -1 N (shoot). The bulb yield data are in a companion report (Díaz-P erez et al, 2018). Briefly, sweet onion total and marketable yields and individual bulb fresh weight augmented quadratically with increasing organic fertilization rate and responses failed to reach a maximum.…”

“…The AEN was calculated by dividing total onion fresh bulb weight (kg · ha -1 ) by the amount of N (kg · ha -1 ) applied to the crop (Bock and Hergert, 1991). Total onion bulb yield data are derived from the same plants of this study and are reported in a companion article (Díaz-P erez et al, 2018).…”

“…The objective of this study was to evaluate the effects of organic fertilization rates on sweet onion plant growth and mineral nutrients composition in leaves and bulbs. In a companion article (Díaz-P erez et al, 2018) from the same trial as this study, we report on the effects of organic fertilization rate on bulb yield and quality.…”

Optimization of the elements of onion production technology in an annual crop in the conditions of central Russia

“…Increasing the production of onions by increasing yields [1][2][3][4][5][6] is seen as the main way for further development.…”

Increasing Organic Fertilizer and Decreasing Drip Chemical Fertilizer for Two Consecutive Years Improved the Fruit Quality of ‘Summer Black’ Grapes in Arid Areas

“…Characterized by a full nutrient spectrum and their slow release, organic fertilizers can increase the organic matter content in soil and the microbial quantity and activity, improve fruit quality, and reduce greenhouse gas emissions (Díaz-P erez et al, 2018;Sharma and Banik, 2014). Tao et al (2017) proved, through 2 years of research, that the substitution of cow manure and biological fertilizers for chemical fertilizers helps maintain the soil nitrogen level, promote cotton yield, and improve nitrogen use efficiency.…”