Biomass accumulation and N status in grain maize as affected by mineral and organic fertilizers in cool climate

Expansion of grain maize to marginally suitable cool climate regions requires a better understanding of the nitrogen (N) economy of the crop. This study was aimed at yield formation in response to different type of fertilizers. Field experiments with short-season maize variety were conducted in Akademija, Lithuania, in 2015 and 2016. In spring, before sowing, ammonium nitrate, pelletized cattle and poultry manures, green waste compost were incorporated at a rate equivalent to 170 kg N ha(-1). Crop N status, based on SPAD measurements, started to differ significantly at the end of the vegetative period with higher values in treatments applied with ammonium nitrate and lower with organic fertilizers. Under favorable conditions maize produced more grain per cob and higher yield. Agronomic N use efficiency (AE(N)) of pelletized organic fertilizers in the unfavorable season (AE(N) 2015: 0.1-4.9) was poor and significantly lower than in the favorable season of (AE(N) 2016: 4.9-11.2).