Effects of fertilization on soil moisture regulation and maize yield in dryland farmland

Objectives To clarify the effects of fertilization on soil moisture and crop yield in dryland will provide a scientific basis for improving resource use efficiency in dryland.

Methods The field trial was conducted in Shouyang, Shanxi Province since 2018, the crropping system is single spring maize. In the experiment, three fertilizer types were set up with no fertilization as the control (CK), and three fertilizer types were set up with organic fertilizer alone (O), chemical fertilizer alone (F) and organic and inorganic combined application (T), and three fertilizer rates (calculated as N) were set under each fertilizer type, including low fertilizer (50 kg/hm²), medium fertilizer (150 kg/hm²) and high fertilizer (250 kg/hm²), a total of 10 treatments. Before maize harvest in 2022 and 2023 and after maize harvest in 2023, the soil water storage efficiency and evaporation of farmland, the water consumption of farmland during the growth period, and the yield and components of maize were investigated.

Results Chemical fertilizer treatment (F) exhibited no significant differences in fallow-period soil water storage, evaporation, or storage efficiency compared to CK. In contrast, organic fertilizer treatment (O) significantly enhanced fallow-period water storage efficiency increased by 89.1% (O) and integrated treatment (T) significantly enhanced fallow-period water storage by 49.1 mm , respectively, while reducing evaporation by 50.7 mm (average). And water storage efficiency increased by 157.6% (T) relative to CK. Notably, O improved water storage efficiency only at the low fertilization rate, whereas T demonstrated consistent benefits across all N rates. Both F and T treatments boosted maize yield by 107.5% and 121.7%, respectively, over CK, with corresponding increases in 100-grain weight (23.9% and 29.1%) and spike number (23.2% and 22.6%). WUE improved by 96.5% (F) and 104.3% (T). Under medium and high N rates, F and T yielded comparable results for yield, grain weight, spike number, WUE, and rainfall use efficiency (RUE), surpassing O in all parameters.

Conclusions Chemical fertilization is capable of enhancing yield and WUE but failed to improve fallow-period soil water storage efficiency, suggesting limited long-term moisture retention benefits. Organic fertilization could improve water storage efficiency but underperformed in yield and WUE, even at high N rates, highlighting its inefficiency for immediate productivity gains. Integrated application of organic and chemical fertilizers could optimize water-fertilizer synergy, ensuring stable, high yields and superior WUE under medium and high N inputs. This strategy is recommended as the optimal fertilization regime for dryland maize, balancing productivity with sustainable resource management.