Excessive Fertilization is Detrimental to Yield and Quality for Onion Grown on High Organic Matter Content Paddy Soils

Abstract

Excess chemical fertilizer applications in historical onion (Allium cepa L.) cultivation areas in Korea may be detrimental to onion yield and quality. A field study was performed to evaluate the effects of chemical fertilizer rates and split applications on intermediate-day onion growth, yield, storage quality, and soil chemical properties in plants established in a paddy soil with high organic matter (OM) content. Rates of chemical fertilization, based on a soil test recommendation (192-13-213 kg·ha −1 N-P-K), and twice the recommended rate were applied and compared to a control treatment not receiving fertilizer. Treatments with twice the recommended rate were applied in three, four, or five splits. Preplant soil contained 46.3 g·kg −1 OM, 728 mg·kg −1 available phosphorus, and 17.3 mg·kg −1 nitrate nitrogen. The highest marketable yield, 58.1 Mt·ha −1 , was achieved at the recommended rate, 7.3%-20.0% more than the double rates and the control. Increased fertilizer beyond the recommended rates and delayed split application times had no positive effect on onion growth or yield but increased culls and accumulated soil electric conductivity, OM, exchangeable K, and NO 3 -N content in soil at harvest. Soil NO 3 -N contents ranged from 110 to 316 mg·kg −1 for split applications at the double rates. The control yielded 40.8 Mt·ha −1 , which was 70.2% of the highest yield. Storage quality was not affected due to treatment, although there were slight increases in bulb rot and physiological disorders at the double rate. Fertilizer applied at higher than the recommended rate for onion is not beneficial.

Effect of Compost and Mixed Oilseed Cake Application Rates on Soil Chemical Properties, Plant Growth, and Yield of Organic Bulb Onions

“…Although higher Effect of Compost and Mixed Oilseed Cake Application Rates on Soil Chemical Properties, Plant Growth, and Yield of Organic Bulb Onions MOC rates resulted in increased soil nutrients, the number of leaves, leaf weight, or bulb weight among application rates of 3, 6, and 9 t•ha -1 MOC were not significantly different. Many studies have revealed that excessive input of nutrients and salt accumulation has negative effects on plant growth and bulb yield (Lee et al, 2012;Shock, 2005;Westerveld et al, 2003). Therefore, the significant increases in the number of leaves, leaf weight, and bulb weight in 2013/2014 compared to those in 2012/2013 were due to higher temperatures in the winter and in April, and to higher Table 5.…”

Influence of Nitrogen and Phosphorus Application on Bulb Yield and Yield Components of Onion (Allium Cepa L.)

“…In both cases, yield and quality of the crop are compromised. Excess application of inorganic nitrogen and phosphorus fertilizers makes luxuriant growth with little effect on yield and causing bulb decays [9,10].…”

Interactions among genotype, environment and agronomic practices on production and quality of storage onion (Allium cepa L.) - A review

“…Conversely, excessive and late-season application of nitrogen, even during the period of bulbification, increases the growth of leaf blades (Brewster 1994); thus, it delays the ripeness of bulbs (Schwartz, Bartolo 1995) and adversely affects their storability (Brown et al 1988;Brewster 1994). Indeed, overfertilization with N, P, K or compost causes the drop of bulb yield or the unbalance of nutrient content at harvest (Abdelrazzag 2002;Lee et al 2012); in addition, the efficiency of fertilizer uptake decreases with the increase of N or K application rates (Lee et al 2011).…”

“…This is a consequence of the increased competition among plants for the available resources and of the limited space for bulb expansion. Leskovar et al 2004;Kadayifci et al 2005;Bolandnazar et al 2007;Kumar et al 2007b;Khokhar 2008;Lee et al 2012;Buckland et al 2013;Caruso et al 2014;Sivesind et al 2012 Mean bulb weight (g) 47.0-643 Hamilton 1998; Kumar et al 2007b;Khokhar 2008;Lee et al 2012;Caruso et al 2014 Total plant dry weight (kg/m 2 ) 1.0-1. 4 Drost, Koening 2001;Caruso et al 2014 Leaf area index (m 2 /m 2 ) 3.2-5.1 Drost, Koenig 2001;Caruso et al 2014 Nutrient requirement and fertilization.…”