Optimized irrigation practices with fertilizer utilization strategies to improve photo-fluorescence efficiency, vascular bundles and maize production in semi-arid regions

The mechanism of irrigation models combined with fertilizer utilization strategies under the biodegradable film mulching could greatly promote crop photosynthesis, vascular bundles structure; resource utilization and maize production are unclear in semi-arid areas. Unfortunately, this mechanism provides a scientific basis for improving irrigation and fertilizer utilization. A field study was carried out during 2021-2022 years. Seven treatments were established: two nitrogen levels: low-N (150 kg N ha^-1) and high-N (300 kg N ha^-1) combined with three different irrigation models: drip irrigation (DI), ridge irrigation (RI) and border irrigation (BI) under the biodegradable film mulching with (CK) treatment have no irrigation, fertilizer and mulching. Our results revealed that DIH treatment considerably increased soil water storage, enhanced photosynthesis rate (Pn) of maize by mainly to facilitate stomatal opening compared to the rest of all treatments. In addition, it also enhances the differentiation of the vascular bundle system and maintains its post silk function under better environmental conditions, greatly improving nitrogen storage in soil and plants, and enhancing maize productivity. DIH and RIH treatments significantly increased net photosynthesis rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), maximum quantum yield of PSII photochemistry (Fv/Fm), and effective quantum yield of PSII photochemistry (ΦPSII), photochemical quenching (qP), non-photochemical quenching (NPQ), and yield were observed, but evapotranspiration (ET) decreased at different growth stages. The results showed that DIH treatment was an effective tillage strategy, which increased biomass yield by 32.6 %, grain yield by 46.0 %, water use efficiency (WUE) by 46.2 %, and nitrogen use efficiency (NUE) by 86.4 % compared to other treatments. Given these results, thus we recommend the drip irrigation combined with a high-N level under a biodegradable film mulching increase photo-fluorescence efficiency, maize production and resource utilization efficiency in semi-arid regions.