RT Journal Article SR Electronic A1 CHEN, Xiaoguang A1 KOU, Meng A1 TANG, Zhonghou A1 ZHANG, Aijun A1 Hongmin, LI T1 The use of humic acid urea fertilizer for increasing yield and utilization of nitrogen in sweet potato JF Plant, Soil and Environment YR 2017 VO 63 IS 5 SP 201 OP 206 DO 10.17221/24/2017-PSE UL https://pse.agriculturejournals.cz/artkey/pse-201705-0002.php AB Humic acid urea fertilizer (HA-N) is a new type of slow-release nitrogenous fertilizer that can enhance utilization rate of urea, and consequently increases crop yield. However, there were few researches about the effect of HA-N on the nitrogen absorption and utilization in sweet potato production. Hence, the effect of HA-N on nitrogen accumulation and distribution, nitrogen use efficiency (NUE), and yield of sweet potato was studied in the field using the <sup>15</sup>N tracer technique. Results showed that HA-N significantly increased the number of storage roots per plant and the average fresh weight per storage root, as well as the yield increased by 29.6% compared with urea fertilizer. Furthermore, nitrogen accumulation of total plant was higher under the HA-N. In addition, HA-N significantly increased nitrogen production efficiency of fertilizer and nitrogen production efficiency. Results of a <sup>15</sup>N tracer experiment revealed that the percentage of nitrogen absorbed by plant from fertilizer increased from 31.1% to 38.7% and NUE increased from 33.5% to 44.8% with application of HA-N when compared with single N treatment, respectively. HA-N significantly increased sweet potato storage root yield, nitrogen absorption and NUE, as well as it reduced the loss of nitrogen fertilizer.