Abstract: To explore the effects of superabsorbent polymer composites (SAPCs) on tree seedling’s growth, a pot experiment with orthogonal design was conducted, using 2-year oldJuglans regia, Prunus armeniaca, Robinia pseudoacacia, and Populus sp. as test objects, and taking leaf area and new shoot height as the growth indicators. The SAPCs were composed of different proportions of superabsorbent polymer, polyaspartic acid, and compound fertilizer. All the test SAPCs promoted the seedling growth, and the promotion effect increased with increasing application dosage. The best proportions of the SAPCs for the seedlings were 20 g superabsorbent polymer, 1.5 g polyaspartic acid, and 15 g compound fertilizer (soil moisture content was 12%) for J. regia, 15 g superabsorbent polymer, 0.5 g polyaspartic acid, and 0 g compound fertilizer (soil moisture content was 12%) for P. armeniaca, 15 g superabsorbent polymer, 0 g polyaspartic acid, and 15 g compound fertilizer (soil water content was 7%) for R. pseudoacacia, and 20 g superabsorbent polymer, 1.0 g polyaspartic acid, and 0 g compound fertilizer (soil moisture content was 7%) for Populus. As compared with the control, the leaf area and new shoot height of the poplar seedlings under the application of the SAPC were increased by 48% and 21%, respectively.

Key words: Iris hexagona, salicylic acid, cadmium, growth.