Synergistic impact of various straw-return methods and irrigation regimes on winter wheat physiological growth and yield

Context or problem

Straw return to the field conserves soil moisture, but its effect on winter wheat growth varies, considering the return method used. Optimal irrigation can improve the effects of returning straw to the field. However, studies on the effects of the straw- return method and irrigation interactions on the physiological growth and yield of winter wheat are limited.

Objective or research question

The purpose of this study was to investigate the effects of two common methods of corn straw-return—burying and mulching— combined with different irrigation regimes on the physiological growth of winter wheat in the North China Plain (NCP). The goal was to establish an economically stable straw-return irrigation regime.

Methods

Straw-burying (SB) and straw mulching (SM) treatments were applied under three irrigation regimes: no irrigation (I₀), 60 mm irrigation during the jointing stage (I₆₀), and 60 mm irrigation during both the jointing and heading stages (I₆₀₊₆₀) during the winter wheat growing seasons from 2020 to 2022. Leaf area index (LAI), stem number, photosynthetic characteristics, photosynthesis-active radiation (PAR) capture rate, dry matter accumulation, and winter wheat yield were measured and calculated. Structural equation modeling (SEM) was used to analyze the correlation between physiological indexes and winter wheat yield.

Results

SB-I₆₀ and SB-I₆₀₊₆₀ maintained higher stem numbers and LAI in winter wheat, compared with SM-I₆₀ and SM-I₆₀₊₆₀. SB-I₆₀₊₆₀ had the highest photosynthetic and PAR capture rates. Under the same irrigation treatment, the spike numbers and yield of SB increased by 2.47–5.73 % and 4.37–9.51 % compared with those of SM, respectively. Under the same straw-return treatment, irrigation improved the straw-return effect, and the yield and dry matter accumulation of winter wheat increased with increasing irrigation. SB-I₆₀₊₆₀ recorded the highest wheat yield. SEM analysis revealed that yield was positively affected by LAI and photosynthetic rate.

Conclusions

The application of SB-I₆₀₊₆₀ increased grain yield, enhancing food security and optimizing the benefits from straw return.

Implications or significance

This study revealed the optimal straw application and irrigation for wheat production, promoting food security in dry regions.