Nutrient loading Artemisia cana seedlings in greenhouse increases nitrogen tissue content and post‐outplanting survival

Abstract

Sagebrush (Artemisia) is a vital habitat component for many grassland species and continued loss, fragmentation, and degradation of sagebrush habitats has increased the need for their restoration. Conventional revegetation methods have resulted in extremely low plant establishment and survival inhibiting the success of sagebrush restoration efforts. During greenhouse production, we sought to improve Artemisia cana seedling quality and post‐planting growth and survival by increasing tissue nutrient content. We conducted a preliminary 12‐week greenhouse study and a subsequent 26‐week greenhouse + 2‐season field study, investigating 12 nutrient loading treatments (application of 70, 105, 175, and 245 mg nitrogen [N] plant−1 at single, constant, exponential, and modified exponential rates). Nitrogen content of seedling leaves and roots at 26 weeks indicated that application of 175 and 245 mg N plant−1 on exponential or modified exponential dosing schedules resulted in nutrient‐loaded seedlings. Seedlings were planted into a cleared plot in Grasslands National Park, SK. After 60 weeks in the field, nutrient‐loaded seedlings had significantly greater survival (75%) than non‐loaded seedlings (65%) and greater crown area (1,351 vs. 1,004 cm2). Rhizomatous reproduction (sprouting) occurred within 4 weeks of planting. New sprouts had disproportionately larger crown areas (2,237 cm2) and greater survival (86%) than planted seedlings. Nutrient loading was an effective method to overcome high mortality that has inhibited restoration outcomes. Where plant materials and resources are limited, nutrient loading could be especially useful by improving seedling survival and crown area without increasing planting densities.

Fall fertilization during nursery production increases nitrogen status of Purshia tridentata seedlings: implications for outplanting

“…Nutrient loading, either through exponential or fall fertilization, has been extensively evaluated for a variety of tree species and stocktypes, including bareroot conifer (Islam et al 2009) and angiosperm (Birge et al 2006) species, container deciduous (Li et al 2012; Zhu et al 2020) and evergreen (Montville et al 1996; Dumroese et al 2005; Timmer & Munson 2011) conifers, and a container angiosperm (Oliet et al 2009). In contrast, for shrubs, few studies have examined exponential fertilization to nutrient load (Dumroese 2003b; Watkinson et al 2021) and to the best of our knowledge, no studies have explored fall N fertilization. In this study, we examined the effects of fall N fertilization on the status, movement, and storage of N in bitterbrush.…”

“…Nutrient‐loaded seedlings generally present better root development than non‐loaded seedlings (Timmer 1997; Salifu & Jacobs 2006), leading to enhanced maintenance of water potential and photosynthetic rates during the subsequent summer after outplanting (Villar‐Salvador et al 2012). This improved physiological status is likely responsible for observed improvements in survival and growth compared to non‐loaded plants, especially for species that grow in Mediterranean and semi‐arid climates subject to expected summer drought (Villar‐Salvador et al 2004; Cuesta et al 2010; Watkinson et al 2021).…”

Light Quality Effect on Internal N Retranslocation in Podocarpus macrophyllus Precultured with Exponential Nutrient Loading

“…Nutrient loading is a practical practice in which the seedling culture is fed with more nutrients than are needed via a large number of applications in order to establish a reserve that can be used to overcome transplant shock [ 11 , 12 ]. This approach was developed in contrast to the conventional fertilizer regime, which only delivered nutrients several times but with a large amount in each application; this practice easily resulted in fertilizer waste through leaching and a low uptake efficiency [ 13 , 14 , 15 ].…”

“…Empirical studies have summarized these states as the stages of deficient uptake, luxury consumption, and overdose toxicity [ 21 , 22 , 23 ]. The optimum rate of supply was characterized as the critical value before toxicity, beyond which any higher rate of supply would result in a deficit of dry mass accumulation and poor transplant performance [ 11 , 14 , 16 , 20 ]. Most of the abovementioned findings were obtained from studies involving tree planting programs for restoration in montane areas, reforestation on abandoned lands, and the establishment of plantations.…”

“…In this study, Podocarpus macrophyllus was chosen as a typical ornamental plant species as it had been proven that it showed significant responses to precultured ENL [ 13 , 23 , 29 ] and a remarkable ability to cope with transplant shocks [ 4 , 24 , 45 ]. Nitrogen (N) was focused on as a typical macro-nutrient that is greatly needed by tree seedlings from nursery culture to the post-transplantation stage [ 11 , 22 , 27 ]. A simulation experiment was conducted in a highly controlled environment to raise seedlings with ENL and to transplant them so that they could receive varied light spectra.…”