Effects of split nitrogen fertilization on post-anthesis photoassimilates, nitrogen use efficiency and grain yield in malting barley

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Split nitrogen applications are widely adopted to improve grain yield and enhance nitrogen use effective in crops. In a twoyear
field experiment at two eco-sites, five fractions of topdressed nitrogen of 0%, 20%, 30%, 40% and 50% were
implemented. Responses of radiation interception and leaf photosynthesis after anthesis, dry matter accumulation and
assimilates remobilization, nitrogen use efficiency and grain yield to fraction of topdressed nitrogen treatments were
investigated in malting barley. Net photosynthetic rate of the penultimate leaf, leaf area index and light extinction coefficient
increased with increasing fraction topdressed nitrogen from 0% to 30%, and then decreased from 30% to 50%. The putative
gross maximum canopy photosynthesis was the highest for fraction of topdressed nitrogen of 30%, which was concomitant
with the highest amount of post-anthesis accumulated assimilates. The remobilization of pre-anthesis stored assimilates
from vegetative organs into grains was hardly significantly affected by fractions of topdressed nitrogen. Grain yield was the
highest for fraction of topdressed nitrogen of 30%, which coincided with the highest plant nitrogen uptake and physiological
and agronomic nitrogen use efficiencies. The enhanced nitrogen use efficiency was corresponding to the improved
photosynthetic nitrogen-use efficiency in the leaves at fraction of topdressed nitrogen of 30%. In conclusion, appropriate
fraction of topdressed nitrogen application on malting barley improved assimilation rate and nitrogen use efficiency resulting
in higher grain yields and proper grain protein content in malting barley.
TidsskriftActa Agriculturae Scandinavica. Section B. Soil and Plant Science
Udgave nummer5
Sider (fra-til)410-420
Antal sider11
StatusUdgivet - 2011

ID: 33747246