Objectives The effects of single-basal application of controlled-release nitrogen (N) fertilizer and drip fertigation technology on soil N leaching and soybean growth and nitrogen nutrition were studied, and the responses differences of soybean cultivars to the two technologies in growth, nodule enzyme activities and yield components were compared.

Methods A field experiment was conducted in Shangqiu, Henan Province in 2023, using two summer soybean cultivars Zhonghuang 301 and Zheng 1307 as the test materials. Three fertilization treatments were set up: conventional fertilization (CF), single-basal application of controlled-release N fertilizer (C_RNF), and drip fertigation (DF). At the seedling, full flowering, seed-filling, and harvest stages, soil samples from the 0–60 cm profile at 10 cm intervals were collected to determine ammonium-N and nitrate-N contents, and soybean plant samples were collected to measure plant height, dry matter of above- and under-ground parts, and nodule enzyme activity. Yield and yield components were determined at harvest. Redundancy analysis was conducted to identify the key factors closely related to the yield of soybean cultivars.

Results 1) For Zhonghuang 301, the C_RNF treatment significantly reduced ammonium-N contents in all soil layers during the V6−R6 stages, compared with CF treatment, whereas DF treatment significantly reduced ammonium-N contents during the R6−R8 stages. For Zheng 1307, both C_RNF and DF treatments reduced nitrate-N contents below the 40 cm soil layer. 2) For Zhonghuang 301, above-ground dry matter under C_RNF and DF treatment increased by 95.40% and 71.06% at the R2 stage, and 12.82% and 26.41% at the R6 stage, respectively, compared with CF. For Zheng 1307, above-ground dry matter under DF increased significantly by 45.45% and 51.04% at the V6 stage, 19.02% and 21.71% at the R2 stage, 13.63% and 12.16% at the R6 stage, and 12.91% and 20.79% at the R8 stage, respectively, compared with CF and C_RNF. The responses of nodule enzyme activity to N treatments differed significantly between the two cultivars. No significant differences were observed among treatments for Zhonghuang 301, whereas that of Zheng 1307 under C_RNF and DF treatments were 33.19% and 59.65% higher than under CF treatment. 3) Yield responses to C_RNF and DF treatments differed significantly between cultivars. Compared with CF, DF treatment increased the yield of Zhonghuang 301 by 26.80%; C_RNF and DF treatment increased the yield of Zheng 1307 by 9.50% and 18.50%, respectively.

Conclusions Both the single-basal application of controlled-release N fertilizer and drip fertigation technologies could reduce nitrogen content in deep soil layers during the early soybean growth stage, decrease the risk of N leaching, alleviate the “nitrogen suppression” phenomenon, enhance nodule enzyme activity at the full flowering stage, ensure nitrogen supply during the late soybean growth stage, and increase dry matter accumulation, thereby improving soybean yield. Drip fertigation performs better than single-basal application of controlled-release N fertilizer as its significant effect on both the cultivars, while single-basal application of controlled-release N fertilizer merely showed promotion on cultivar Zhonghuang 301.