Abstract: To investigate the comprehensive effects of different water management modes combined with slow/controlled release urea on soil fertility in maize fields, three water management modes, namely flood irrigation, sprinkler irrigation, and drip irrigation, were set up, and for each mode, treatments with and without combined application of slow/controlled release urea were established, and soil pH, organic carbon content, total nitrogen content, and total phosphorus content were measured. The results showed that under the treatments without combined application of slow/controlled release urea, all three water management modes alleviated soil acidification and increased soil organic carbon content, total nitrogen content, and total phosphorus content, with the drip irrigation treatment exhibiting the best performance. After the combined application of slow/controlled release urea, all indicators were further improved, and the increases were significantly greater than those in the corresponding treatments without combined application of slow/controlled release urea.At the late stage of maize field management, the soil pH under the drip irrigation with combined application of slow/controlled release urea treatment was 6.73, the soil organic carbon content was 15.6 g/kg, the total nitrogen content was 2.12 g/kg, and the total phosphorus content was 0.79 g/kg, all of which were superior to those of the other treatments. Drip irrigation with combined application of slow/controlled release urea achieved the best effect on improving soil fertility in maize fields.

Key words: water management mode, combined application, slow/controlled release urea, maize field, soil fertility