Soil Nitrogen Fertilization Increases Yeast Assimilable Nitrogen
Total Page:16
File Type:pdf, Size:1020Kb
HORTSCIENCE 55(8):1345–1355. 2020. https://doi.org/10.21273/HORTSCI15028-20 The rapid growth of the hard-cider (henceforth referred to as cider) industry within the United States during the past Soil Nitrogen Fertilization Increases decade offers an opportunity for apple [Malus ·domestica (Borkh.)] growers in the Yeast Assimilable Nitrogen United States to expand and diversify pro- duction, and potentially to increase their Concentrations in ‘Golden Russet’ and profitability with the cultivation of heirloom and high-tannin cultivars specifically for ci- der production (Peck and Knickerbocker, 2018; ‘Medaille d’Or’ Apples Used for Cider Peck et al., 2013). Many high-acid- and high- tannin-concentration cultivars sought after by Production cider producers for the sensory attributes of their juice are not available in sufficient Adam D. Karl and Michael G. Brown quantities to meet demand within the United School of Integrative Plant Science, Horticulture Section, Cornell University, States (Pashow, 2018). However, many of 121 Plant Science Building, Ithaca, NY 14853 these cultivars possess horticultural traits that pose challenges to their production in com- Sihui Ma, Ann Sandbrook, and Amanda C. Stewart mercial orchards, such as biennial bearing Department of Food Science and Technology, Virginia Polytechnic Institute and vigorous vegetative growth (Merwin and State University, HABB1 Room 401F, 1230 SW Washington Street, et al., 2008). Growers need information on Blacksburg, VA 24060 how horticultural management practices im- pact economic returns, fruit quality, and the Lailiang Cheng sensory attributes of the finished ciders to School of Integrative Plant Science, Horticulture Section, Cornell University, remain competitive and continue improving the quality of ciders available in the U.S. 120 Plant Science Building, Ithaca, NY 14853 market. Anna Katharine Mansfield Nitrogen fertilization is a little studied area of cider apple orchard management that Department of Food Science, Cornell AgriTech, 107 Food Research Lab, potentially impacts productivity, fruit tannin Geneva, NY 14456 concentrations, fermentation kinetics, and cider sensory attributes (Boudreau et al., Gregory M. Peck 2017a; Lea and Beech, 1978; Santos et al., School of Integrative Plant Science, Horticulture Section, Cornell University, 2016; Wargo et al., 2003). There are cur- 121 Plant Science Building, Ithaca, NY 14853 rently no standard nitrogen fertilization rec- 3 ommendations for cider apple orchards in the Additional index words. amino acid, fermentation, hard cider, Malus domestica Borkh., United States, so growers typically follow nitrogen fertilization, tree growth, yeast assimilable nitrogen guidelines for fresh market or processing Abstract. The recent growth in the U.S. hard-cider industry has increased the demand for apple orchards. Sufficient nitrogen for tree cider apples (Malus 3domestica Borkh.), but little is known about how to manage growth, photosynthesis, and fruit develop- orchard soil fertility best to optimize horticultural performance and juice characteristics ment is essential, but excessive nitrogen fer- for these cultivars. To assess whether nitrogen fertilizer applied to the soil can improve tilization can impact fruit quality and flower bud cold hardiness negatively (Raese et al., apple juice and cider quality, calcium nitrate (CaNO3) fertilizer was applied at different rates to the soil beneath ‘Golden Russet’ and ‘Medaille d’Or’ trees over the course of 2007). Moderate nitrogen fertilization rates, three growing seasons. The experiment started when the trees were in their second leaf. with target total leaf nitrogen content be- The trees were cropped in their third and fourth leaf. At the end of the first growing tween 2.2% and 2.4%, are therefore recom- season of the experiment, the greatest fertilizer rate increased tree trunk cross-sectional mended for hard-fleshed and processing area (TCSA) by 82% relative to the control, but this difference did not persist through to apple cultivars (Stiles and Reid, 1991). In- the end of the study. Yield and crop load were unaffected by the nitrogen fertilization sufficient nitrogen can reduce fruit size, treatments. Increasing the nitrogen fertilizer rate correlated positively with more yield, and SSCs in fruit (Fallahi, 1997; Lea advanced harvest maturity in ‘Golden Russet’ fruit, which resulted in greater soluble and Beech, 1978). Greater nitrogen content solid concentration (SSC). Fruit from the greatest fertilizer rate treatment had an of apple trees has been correlated with de- average starch pattern index (SPI) that was 1 U greater than in the control, and an SSC creased red and increased green coloration of that was 3% greater than the control. The fertilizer treatments did not affect juice pH, fruit peels, less firm flesh, and reduced stor- titratable acidity (TA), or total polyphenol concentrations. Yeast assimilable nitrogen age capacity (Fallahi, 1997; Raese et al., (YAN) concentrations were increased by nitrogen fertilization for both cultivars in both 2007; Wargo et al., 2003, 2004). Because harvest years. The greatest fertilizer treatment increased juice primary amino nitrogen cider fruit is in limited supply in the United by 103% relative to the control. Greater nitrogen fertilization rates correlated positively States, it is typically milled and pressed with less hydrogen sulfide production during the fermentation of ‘Golden Russet’ juice within several weeks after picking; thus, peel from the first, but not the second, harvest. During the first year, cumulative hydrogen color, flesh firmness, and long-term storage sulfide production for the ‘Golden Russet’ control treatment was 29.6 mg·L–1 compared capabilities are less important fruit-quality with the ‘Golden Russet’ high treatment, which cumulatively produced 0.1 mg·L–1. characteristics than they are for fresh-market Greater maximum fermentation rates and shorter fermentation durations correlated apples. positively with increased fertilization rate for both cultivars after the second harvest. Within the context of producing apples High treatment fermentations had maximum fermentation rates 110% greater, and for cider, increasing fruit nitrogen concentra- fermentation durations 30% shorter than the control. Other horticultural and juice- tion may be beneficial for alcoholic fermen- tation. YAN, which is defined as the nitrogen quality parameters were not affected negatively by the CaNO3 treatments. In orchards producing apples specifically for the hard-cider industry, nitrogen fertilizer could sources metabolized by Saccharomyces cer- increase juice YAN, thus reducing the need for exogenous additions during cider evisiae yeast during fermentation, is often a production. limiting factor for cider fermentation rates (Bell and Henschke, 2005; Boudreau et al., HORTSCIENCE VOL. 55(8) AUGUST 2020 1345 2017b). YAN is composed of free amino can improve tree growth and yield, and fertilizer containing 15.5% nitrogen by nitrogen (FAN), ammonia (NH3) ions, and simultaneously reduce the need for exoge- weight (YaraLiva Tropicote, North East some short oligopeptides (Bell and Henschke, nous YAN additions. Because apple trees are Lincolnshire, UK). The treatments were reap- 2005). Deficient YAN concentrations can perennial crops that rely on nitrogen reserves plied to the same trees each year. Control-, result in incomplete and/or slow fermen- from the previous growing year to support low-, medium-, and high-treatment trees re- tations that produce inferior-quality prod- initial growth and fruit set, multiyear studies ceived an equivalent of 0, 28, 56, and 112 ucts (Bell and Henschke, 2005). Low of nitrogen fertilization in orchards are useful kg·ha–1 nitrogen each year, respectively. YAN concentrations are also known to in- to elucidate the ramifications for different CaNO3 was applied in two equal aliquots crease the production of hydrogen sulfide management strategies (Cheng et al., 2004). by spreading the granules in a ring around (H2S) during fermentation, a common defect Over the course of three growing seasons, each tree starting 15 cm and extending to 40 in ciders because it smells like cabbage or different rates of CaNO3 fertilizer were ap- cm away from the trunk. The first annual rotten eggs (Boudreau et al., 2017b; Jiranek plied each spring to ‘Golden Russet’ and applications occurred on 19 Apr. 2016, 18 et al., 1995). H2S is an intermediary com- ‘Medaille d’Or’ apple trees. These cultivars Apr. 2017, and 18 Apr. 2018, when the trees pound formed from the reduction of sulfate or were selected because of their popularity in were about at half-inch green of bud devel- sulfite to synthesize the sulfur-containing cider production. The study began when trees opment (Agnello et al., 2019). The second amino acids cysteine and methionine; excess were in their second year after planting and application was applied about 4 weeks later, H2S frequently permeates the yeast cell continued through their fourth year. Fruit was on 16 May in each year of the study. membrane in low YAN fermentations when harvested in the third and fourth years of the The study was designed as a randomized sufficient amino acid precursors are not avail- study. The overall goal of this research was to complete block, with four double-tree repli- able to sequester sulfide (Jiranek et al., 1995; assess the impact of nitrogen fertilization on cations per treatment. Blocks were desig- Ono et al., 1999; Ugliano et al., 2011). Cur- tree growth, yield, fruit and juice quality, and nated