The effect of fertilizer type on nitrogen uptake by maize from recently formed soil organic matter^#

Background Soil organic matter (SOM) formed under legume‐based grasslands may serve as an important source of nitrogen (N) for subsequent maize growth. Aim We aimed at studying effects of fertilizer type (organic and mineral N and phosphorus (P) fertilizers) on N release from recently formed SOM and N utilization by plants. Methods The effects of mineral and organic (meat and bone meal) N and P fertilization on SOM turnover were examined under maize ( Zea mays L.) on a sand loamy typic hapludult in an outdoor pot experiment over 55 days. The plant uptake of N derived from recently formed SOM was investigated by dual labeling this SOM pool with 15 N and 13 C. Results Organic and mineral fertilized maize acquired similar amounts of N derived from recently formed SOM, which was twice as high as for unfertilized plants. Rhizosphere soil with organic fertilizer had higher 13 C loss than unplanted soil, whereas no extra 13 C was lost under mineral fertilization. On the contrary, a lower 13 C loss from planted compared to unplanted soil was observed in unfertilized soil. Conclusions Both mineral and organic fertilizers increased plant growth and N uptake, whereas only organic fertilizers accelerated SOM turnover in the rhizosphere as compared to bulk soil. Thus, this study implies that the fertilizer types differently affected the mechanisms controlling the utilization of N bound in recently formed SOM.