The aftereffect of winter wheat on pea yield, nitrogen surplus and nitrogen use efficiency in different cropping systems
The present study is part of a framework for researching the use of the field pea in cropping systems in order to improve its economic and environmental output. The specific aim was to investigate the effect of differently fertilised preceding winter wheat on subsequent field pea output in the same crop rotation. The field experiment was conducted in Tartu county, Estonia, in 2012–2017. Seven different cropping systems were investigated: four conventional with different treatments of mineral nitrogen fertilisers and three organic including catch crops and cattle manure treatment. The DM yield of field pea in winter wheat mineral N treatments 50–150 kg N ha-1 was 2699–2852 kg ha-1, which was 33% higher than in the organic systems. There were no significant differences (p < 0.05) in nitrogen use efficiency (NUE) and N surplus between 50–150 kg N ha-1. The first 20 kg ha-1 mineral N with P25 and K95 gave a significantly higher pea yield compared to the treatment without mineral N. The catch crops reduced agronomic NUE and increased N surplus in the organic cropping systems.