Impact of weather on yield components of spring cereals over 30 years

This investigation examines the relationships between atmospheric influences and the grain yield of spring cereals (spring barley, oats). Also, three yield components - crop density (ears/panicles m(-2)), number of kernels per ear/panicle and kernel weight - are considered. The study uses data of a long-term held experiment at Berlin-Dahlem for the period between 1962 and 1996. The results show that grain yields as well as the formation and differentiation of yield parameters are clearly influenced by weather fluctuations. Altogether it is possible to explain nearly 60% of the grain yield variability by meteorological variables for both species. The yield components are strongly influenced by weather in different months: the number of kernels per earl panicle in May during spikelet formation and development, the crop density in June during tiller reduction (declining number of tillers due to intraspecific competition effects), and, finally, the kernel weight in June and July during grain filling. Grain yields of spring barley are mainly influenced by crop density and number of kernels per ear, for the grain yield of oats, the most important component is the number of kernels per panicle, which depends highly on the weather conditions in May. (C) 1999 Elsevier Science B.V. All rights reserved.