Morphological and Anatomical Characterization of Leaf Burn in Corn Induced from Foliar‐Applied Nitrogen¹

Abstract

Foliar applied nutrients have been used to overcome nutrient deficiencies on a variety of crops; however, leaf burn is often a problem. Corn (Zea mays L.) Plants were treated with 120 g N L−1 from urea to study the leaf burn phenomenon. A 4‐µL drop applied to the adaxial leaf surface was observed at 2‐h intervals for 8 h. Leaf samples were studied with dissecting, compound, and scanning electron microscopes for changes resulting from the application of foliar applied fertilizer salts. Damage observed under the dissecting microscope after 2 h consisted of a darkening in the epidermal cells. After 8 h, the epidermis was desiccated, sunken, and discolored, forming a lesion on the leaf surface. Slides of leaf sections showed wrinkling and collapse of epidermal cells at 4, 6, and 8 h. Disorganization of mesophyll was observed after 8 h. Scanning electron microscope (SEM) micrographs revealed collapsed and wrinkled epidermal cells with sunken stomates after 2 h. Events associated with visual damage appear to be related to water loss since epidermal and mesophyll cells become desiccated.

Enhanced Efficiency Foliar Nitrogen and Pyraclostrobin Applications for High Yielding Corn

“…Although this study found only minor disease severity differences between N treatments, probably due to increased injury caused by 30-0-0-0 at 28 L ha -1 , other research saw no effect of N management on the severity of northern corn leaf blight (Bair et al, 1990). Foliar-applied fertilizer has caused lesions that resulted in desiccation of epidermal cells (Gamble & Emino, 1987;Shetley et al, 2015), which may allow greater infection of leaf tissue when foliar disease is present. In 2011, common rust was not present at Novelty or Albany, and it was less than 2% at Novelty in 2010 (Tables 6 and 7).…”

“…The reduction probably stemmed from increased crop injury from the 30-0-0-0 application (Table 4). Leaf injury usually occurs shortly after applying foliar N and results in necrotic lesions (Gamble and Emino, 1987). Other researchers have reported yield reductions (6.7%) when applying N near silking stage (Harder et al, 1982).…”

Hygroscopic particles on leaves: nutrients or desiccants?

“…While the main application of foliar fertilization is to rapidly improve nutrient deficiencies, plant response is enormously variable and difficult to reproduce Ebert 2005, Fernandez andEichert 2009). In addition, the plant may be damaged by ''foliar burn'' or ''foliar scorch,'' suggesting that local desiccation is a frequent drawback (e.g., Gamble and Emino 1987). Urea frequently causes leaf burn (Bremner 1995), but this is not due to toxic amounts of ammonia (Krogmeier et al 1989).…”

“…Foliar nutrition can potentially overcome acute nutrient deficiencies of crops and fruit trees but its success is poorly predictable and complicated by ''leaf burn'' (e.g., Gamble andEmino 1987, Fernandez andEbert 2005). A similar agricultural technique is ''chemical desiccation,'' whereby hygroscopic but chemically very different salts and acids are sprayed on the leaves to kill potato vine before harvest (Wilson et al 1947, Murphy 1968) and to mimic drought in plant breeding (Blum et al 1983a, Nicolas and Turner 1993, Royo and Blanco 1998.…”

Corn Yield Response to Pyraclostrobin with Foliar Fertilizers

“…Inconsistencies most likely arose from varied environmental conditions during application, such as time of day, temperature, and relative humidity. Hotter and/or dryer conditions may have caused sprays to dry quicker on foliar surfaces, causing increased salt concentrations and leading to greater cellular damage (Neumann & Prinz, 1975;Gamble & Emino, 1987).…”