How do integrated agronomic practices enhance sunflower productivity and stability in saline-alkali soils of arid regions? Evidence from China

Abstract

Context

Achieving stable sunflower yield (Y) in saline-alkali soils is challenging. Integrated agronomic practices, including irrigation on crop demand (IOD), straw return (SR), and organic substitution (OS), offer promising solutions, but their combined effects remain unclear.

Objective

This study aimed to evaluate the combined effects of IOD, SR, and OS on soil microenvironment, sunflower Y, Y stability, nitrogen uptake (NU), and nitrogen partial factor productivity (PFP_N) in arid regions.

Methods

A field experiment was conducted over two growing seasons (2022–2023) in northwest China, with treatments including different combinations of IOD, SR, OS, conventional drip irrigation (CDI), chemical fertilizer only (CK), and straw not return (SNR). Pearson and random forest analyses were applied to evaluate correlations, and rank the relative importance of each indicator to Y, respectively.

Results

The IOD+SR+OS treatment significantly improved sunflower Y and stability, achieving an average yield of 4.42 t hm⁻², with a high sustainability yield index (SYI = 0.96) and a low coefficient of variation (CV = 2.9 %). Compared to CDI+SNR+CK, it increased PFP_N by 79.18 % and NU by 49.39 %. This treatment also enhanced soil nitrogen storage (NS), while reducing salt storage (SS), optimizing soil microenvironment for crop growth and NU. Pearson correlation analysis revealed strong positive correlations between PFP_N, NS, and Y (P ≤ 0.01), while SS negatively correlated with Y (P ≤ 0.001). Random forest analysis identified SS and NS as key factors influencing sunflower Y.

Conclusions

Integrating IOD, SR, and OS significantly improves sunflower Y and stability in saline-alkali soils by optimizing soil water, salt, and nitrogen distribution, supporting sustainable agriculture in arid regions.