Improving soil properties and maize yield by integrating soil and crop management measures in coastal saline area

Objectives The effects of integrating soil and crop management on soil properties and maize yield in the coastal saline area was studied for the efficient use of coastal soil.

Methods The local field experiment commenced in 2016 in the Kenli District of Shandong Province. There were four treatments in total. Two were the local farmers’ practices with or without applying soil remediation agent (ISM and FP). The other two were improved crop management with or without applying soil remediation agent (ISCM, ICM). In the improved crop management, the ZD958 maize cultivar was replaced with DH618; the plant density was increased from 7.5×10⁴ to 9.0×10⁴ plants/hm², the N–P₂O₅–K₂O dosages were adjusted from 280–90–60 to 200–135–60 kg/hm², and desulfurized gypsum 30 t/hm² and cow dung 15 t/hm² were used as remediation agents. Soil samples at 0–60 cm depth were collected after spring maize harvest in 2020. The samples were collected at 20 cm intervals to determine soil properties and maize yield, and the yield components in the same year were investigated.

Results Compared with FP, ISM (P < 0.05) decreased exchangeable Na⁺ content and exchangeable sodium percentage (ESP) values by 17.1% and 28.4%, increased topsoil (0–20 cm) organic carbon (SOC) and total nitrogen (TN) contents by 7.2% and 10.7%, and increased maize yield by 8.0%. ICM increased biomass accumulation at the maturity stage by 19.7%, N partial productivity by 61.7%, grain N content by 6.2%, and yield by 15.5%. ISCM (P < 0.05) reduced exchangeable Na⁺ content and ESP values by 31.4% and 41.1%, increased SOC and TN storage by 15.8% and 17.4%, increased aboveground N uptake by 29.5%, and increased N partial productivity by 66.2%. Further, ISCM recorded the highest yield of 11.24 t/hm², which was 18.8% higher than FP.

Conclusions The application of soil remediation agents, increased plant density, and adjusted maize cultivar and fertilizer input in the coastal saline area increased the storage of SOC and TN, reduced the content of soil exchangeable Na⁺ and ESP, and promote maize dry matter accumulation. It also increased N uptake, improved N use efficiency, soil quality, and maize yield.