Ethephon Application and Nitrogen Fertilization of Irrigated Winter Barley in an Arid Environment
Lodging in barley (Hordeum vulgare L.) can result in grain loss, lower seed quality, increased disease, high grain moisture, reduced harvest efficiency, and lower milling grade. Application of N fertilizer to achieve high barley yields often results in increased lodging. Consequently, N applications are often reduced in order to lessen the potential for lodging. Use of plant growth regulators may permit higher N application rates without increased lodging. Field studies were conducted in an irrigated arid environment during 1986 and 1987 on Fruita sandy clay loam (fine-loamy, mixed, mesic Typic Haplargid) soil. Ethephon [(2-chloroethyl) phosphonic acid] was applied at 0.42 kg a.i. ha−1 to irrigated winter barley that received 56, 112, 168, and 224 kg ha−1 of spring-applied N. The 1986 data indicated that, in the absence of lodging, ethephon did not affect barley grain yields. Ethephon increased grain yields in 1987 in association with reduced lodging. Plant height response to ethephon was similar across N rates. Ethephon shortened internode lengths on the upper portion of the culm and reduced lodging of winter barley grown at high N rates. Ethephon did not affect spikes m−2, kernel mass, kernels spike−1, or seed N content in either year. Application of higher N rates than traditionally used in irrigated winter barley increased grain yield and seed N content. In years when lodging occurred, ethephon was effective as an antilodging agent.
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