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A 9-year-old poplar plantation was cultivated by drip irrigation and furrow irrigation in the sandland of ancient Yongding River in Daxing District of Beijing. Soil moisture sensors were set up in main soil layers (20, 40, 60 and 80 cm) with most roots distributed. The intelligent collector was used to monitor soil moisture in real time to investigate soil moisture dynamics and forest productivity under different irrigation patterns. The results showed that after a single effective drip irrigation and furrow irrigation, the vertical depth of wet body formed along the tree row was 72 cm and 143 cm, and the cross-sectional area of wet body was 0.41 and 2.71 m 2 , respectively. The amount of irrigation was 79.20 and 776.47 m 3 ·hm -2 respectively, with the latter being 9.8 times of the former. The duration was almost the same (11 d) when soil moisture went down to the level of slight water deficit (the soil moisture content=70% of field moisture carrying capacity) in the 0-40 cm layer where poplar absorption roots mainly distributed. From April to October 2019, total irrigation amount of three times furrow irrigation in May, July and September was 2329.41 m 3 ·hm -2 , and that of drip irrigation was 1425.60 m 3 ·hm -2 , 18 times in total. There were 109 days during which poplar trees suffered moderate water deficit (the soil moisture content ≤60% of field moisture carrying capacity) under furrow irrigation, whereas no moderate water deficit happened under drip irrigation during the whole growing season. Annual increment of standing volume was 38.92 m 3 ·hm -2 under drip irrigation, which was 1.5 times of that under furrow irrigation (25.43 m 3 ·hm -2 ). Our results suggested that different irrigation resulted in significant difference in productivity of poplar plantation.