Giessen long-term field experiment 'biological nitrogen fixation' - plant-available phosphorus

This data set was created in the frame of the project Soil3 - Sustainable Subsoil Management, which aims at optimizing the utilization of the soil volume for plant growth. The aim was to reveal the effects of 34 years of legumes (crimson clover, fava beans) and non-legumes (maize) in rotation combined with different fertilization regimes (no fertilization, PK fertilization, NPK fertilization) on soil phosphorus (P) storage throughout the uppermost meter of the soil profile. Calcium acetate lactate-extractable phosphorus (PCAL), considered as a proxy for plant-available P in German soils, were measured according to Schüller (1969). Although P storage tended to show a minimum at 30–50 cm, the coefficient of variation was relatively high and no significant differences in plant-available P were detected. However, the models indicated a likely increase in plant-available P under fava beans compared with the clover system.

Research category: plant nutrition
Research question: Arable subsoil can act as an insurance system for crops in terms of water and nutrient supply. We aimed to analyse nutrient (P, K) stocks in top- and subsoil of the LTFE 'Biological Nitrogen Fixation' at Gießen to reveal effects of fertilization regime on nutrient stocks.