Increasing sunflower productivity by mitigating soil salt stress through biochar-based amendments

The utilization of biochar encountered numerous constraints in achieving increased production and addressing soil salinity issues when employed in isolation. It is essential to take specific measures to maximize its advantages. A two-season field experiment was conducted for planting sunflower using biochar (C, 15 t ha−1) and fulvic acid (FA, 0.15 t ha−1) amendment in the Hetao Irrigation Region in Inner Mongolia, China. The results indicated that the C+FA treatment led to a 28.9% reduction in soil salinity levels at a depth of 0–20 cm after the two-year sunflower cultivation when compared to CK. Analysis of ions revealed that the increase in the ratio of CO32- and HCO3− led to soil pH rise. The C+FA treatment showed 22.64 g kg−1 organic matter content at depth of 0–20 cm after harvested in the second year. The growth characteristics of sunflowers were enhanced, along with an improvement in the plant's nitrogen nutrition. The C+FA treatment resulted in a seed yield of 8.5 t ha−1, indicating a twofold increase in comparison to the CK treatment. The research indicates that utilizing biochar-based amendments offers practical benefits for promoting saline agricultural development in arid and semi-arid lands.