Nitrogen fertilizing of continually grown barley
1998
Orphanos, P.I. (Agricultural Res. Inst. (Cyprus))
Experiments were carried out over the period 1988-96 with continually grown Athenais barley for grain production in farmers fields, testing N rates applied at sowing, ranging from zero to 120 kg/ha. Nitrate-N was monitored in the 0 to 60 cm soil layer, sampled just prior to sowing in late November. The experimental period was drier than expected with very erratic rainfall distribution. Of the 64 year/site combinations recorded there was no response to N in 32, response only to the 30 kg N/ha rate in 22, and further response to 60 kg N/ha in 10. Application of excess N did not reduce yield.The amount of nitrate N in the 0 to 60 cm layer at sowing was not a useful criterion for fertilizing. When grain yield was 2.5 t/ha, grain size was not influenced by N fertilizing, but when yield was lower, increasing N reduced grain size. This indicates that N increased the number of grains in excess of those that could be properly filled. When grain yield was 1.5 t/ha, grain N increased to 2.5 and straw N to 0.9 with application of 60 kg N/ha. However, at higher yield levels the increase was only up to 2.0 for the grain and 0.5 for the straw.
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