Two-way NxP fertilisation experiment on barley () reveals shift from additive to synergistic N-P interactions at critical phosphorus fertilisation level.

In a pot experiment, we investigated synergistic interaction of N and P fertilisation on barley biomass () on both shoot and root level with the aim to determine whether N-P interaction would be the same for all levels of N and P fertilisation. We further aimed to determine whether there was a critical level of N and/or P fertilisation rate, above which, a decrease in resource allocation to roots (as nutrient availability increased) could be demonstrated. Barley plants were grown from seed on a nutrient poor substrate and subjected to a two-way NxP fertilisation gradient using a modified Hoagland fertilisation solution.

Fertilizer addition lessens the flux of microbial carbon to higher trophic levels in soil food webs of grassland.

Roots and root-derived C compounds are increasingly recognised as important resources for soil animal food webs. We used (13)C-labelled glucose as a model C compound representing root exudates to follow the incorporation of root-derived C into the soil animal food web of a temperate grassland over a period of 52 weeks. We investigated variations in glucose C incorporation with fertilizer addition and sward composition, i.