Long-term nitrogen and phosphorus balances for spring barley (Hordeum vulgare L.) cultivation as affected by primary tillage of a Nordic clay soil

In conservation agriculture no -tillage and reduced tillage are used to increase the sustainability of cultivation. There is, however, a paucity of data on the long-term effects of no -tillage and reduced tillage management on the nutrient balances for grain production in a cool and humid climate. This information is relevant for evaluating the effects of primary tillage systems on environmental risks and nutrient input use efficiency of cultivation. In the current study, we examined the long-term effects of primary tillage methods on grain and nitrogen (N) and phosphorus (P) yields, and N and P balance for spring barley (Hordeum vulgare L.) cultivation on a Nordic clay soil (Vertic Endostagtic Cambisol) in 2000-2019. Three types of primary tillage were compared: mouldboard ploughing to 20-25 cm depth, stubble cultivation to 10-15 cm depth (later reduced tillage) and no -tillage. The trial was left without P fertilizer since 2008. Based on the current results, ploughing and reduced tillage were comparable primary tillage methods but no -tillage increased the N and P balances. Barley yield was 12-13% higher for ploughed and reduced tillage treatments than for no -tillage. N yield was 18% and 21% higher and P yield 12% higher with ploughed and reduced tillage compared with no -tillage, respectively. N balance was 43.6, 41.8 and 52.5 kg/ha with ploughing, reduced tillage and no -tillage and P balance was -5.9 kg/ha with ploughing and reduced tillage and -4.5 kg/ha with no -tillage, respectively.