Abstract:

This study investigated the effects of coconut coir mulching on wheat growth, soil physical and chemical properties, and bacterial community structure in saline-alkali environments, aiming to provide theoretical and technical support for wheat cultivation under such conditions. Using ‘Yangmai 29’ as the test material, a field experiment was conducted with four treatments, including blank control (no fertilization, rice straw removed from the field), conventional control [base application of compound fertilizer (15:15:15) 600 kg/hm², jointing fertilizer urea 300 kg/hm², rice straw removed from the field], straw cover [base application of compound fertilizer (15:15:15) 600 kg/hm², jointing fertilizer urea 300 kg/hm², rice straw cover thickness 2 cm], and coconut coir cover [base application of compound fertilizer (15:15:15) 600 kg/hm², jointing fertilizer urea 300 kg/hm², coconut coir cover thickness 2 cm]. The effects of coconut coir mulching on wheat yield, soil physical chemical properties, and soil bacterial community structure were analyzed. The results demonstrated that coconut coir mulching significantly reduced soil water evaporation, thereby mitigating surface salt accumulation. It enhanced soil nutrient availability and organic matter content, and the contents of soil alkali-hydrolyzable nitrogen, available phosphorus, available potassium and organic matter were 4.44%, 2.26%, 1.22% and 4.51% higher than those of the conventional control, respectively. At the same time, the soil structure was significantly improved. Compared with the conventional control treatment, the emergence rate (31.57%) and yield (11.54 %) of wheat were significantly increased under coir mulching treatment, showing a significant effect of controlling alkali and inhibiting salt. In addition, the coconut coir mulching treatment changed the soil bacterial community structure, significantly increased the abundance of plant growth promoting bacteria (GPA) with nitrogen fixation function, and reduced the abundance of some functional bacterial groups (FBA, CTA) that may be involved in denitrification and other processes, thus potentially improving the nitrogen fixation capacity of the soil. In summary, coconut coir mulching is a feasible agricultural measure to effectively improve saline-alkali soil and promote wheat yield, and has important application prospects.

Key words: wheat growth, improvement of saline-alkali land, coconut coir mulching, soil physical and chemical properties, microbial diversity