Long-term fermented organic fertilizer application reduce urea nitrogen-15 loss from plastic shed agricultural soils

Continuous application of fermented organic fertilizer can improve soil quality, while the performance of nitrogen (N) in the improved soils is rarely investigated. To investigate the fate of applied N in the soils with organic management history, the ¹⁵NH₂CO¹⁵NH₂ (¹⁵N abundance of 19.6 %) was employed as the exogenous N source to conduct an experiment in the Chinese cabbage and tomato rotation system under plastic shed condition. The cultivated soils have received 15-year of effective microorganism (EM) fermented organic fertilizer (EM-OF), N, P, K inorganic fertilizer (NPK-IF) and no fertilizer (NoF). The ¹⁵N use by cabbage and tomato, the soil ¹⁵N forms, as well as the ¹⁵N distribution were observed. Results showed that the ¹⁵N use efficiency of cabbage in the EM-OF, NPK-IF and NoF soils were 55.1 %, 37.3 % and 26.6 % respectively, showing significant (p ≤ 0.05) differences. The succeeding crop tomato could take up the soil residual ¹⁵N, and the highest ¹⁵N reuse efficiency was 7.1 % that detected in the NoF soil. The total ¹⁵N loss (6.0 %) from the rotation system was the lowest in the EM-OF soil, compared to that in the NPK-IF and NoF soils. It was concluded that the long-term fermented organic fertilizer applied soils can reduce urea ¹⁵N loss from plastic shed agriculture, mainly through improving the in-season crop ¹⁵N use efficiency.