Nitrogen use efficiency by winter barley under different climatic conditions
1993
Gonzalez Ponce, R. | Salas, M.L. | Mason, S.C.
The proportion of straw and grain as well as of nitrogen (N) in the barley (Hordeum vulgare L.) plant was greatly changed by the distribution of rain in the pre- and post-anthesis periods and by the existence of air temperatures above 30 degrees C during grain filling along with N fertilizer rate. The response of barley to N rates of 0, 40, 80, 120, and 160 kg N/ha was studied over a three-year period. Adequate rainfall in the pre-anthesis period, little rain in the post-anthesis period, and air temperatures above 30 degrees C during the hard dough stage of the grain development, produced high N translocation to the grain as well as a positive response on grain yield and N content in the grain up to a fertilizer rate of 118 kg N/ha. Above this rate, grain yield decreased, while the N content in grain continued to increase. Optimum moisture conditions during the pre- and post-anthesis periods, and mild temperatures during the grain filling period, produced a good grain yield response to N fertilizer rate, increases up to 131 kg N/ha without varying the N content in grain. The N translocation efficiency was somewhat lower than low rainfall in the post-anthesis period. Low rainfall in the pre-anthesis period and air temperatures above 30 degrees C in the early milk stage of the grain made grain filling difficult, even when the rainfall was sufficient in the post-anthesis period. Hence under these conditions, N fertilizer rate did not increase the grain yield, but the N content and the N-translocation efficiency decreased with increasing N fertilizer rates.
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