Total straw return combined with subsoiling improves water storage in soil and water use efficiency of maize

Objectives We conducted a field experiment to optimize the combination of tillage method and straw return amount, in order to support the sustainable and efficient maize production in Xiliao River Plain Irrigation Area, Northeast China.

Methods A positioning experiment was carried out for three years at the Experimental Demonstration Base of Tongliao City Animal and Plant Science Research Institute, the test crop was maize. Nine treatments were included in the experiment: rotary tillage without straw return (RT), clearing stubble and straw in ridge and deep spin in strip cultivation (SCN), clearing stubble and return all straw followed with deep rotary tillage in strip (SCA), subsoil tillage without or with straw return (STN, STA), deep plow tillage without or with straw return (PTN, PTA), no-tillage without or with straw return (NTN, NTA). From 2018 to 2020, soil physical properties, moisture conditions, and water use efficiency were investigated each year. The key soil factors affecting water use efficiency (WUE) were also explored.

Results Among several tillage methods, totals straw return following subsoiling (STA) showed the best effect on decreasing soil bulk density and increasing porosity of 0−45 cm soil layer, and improving the water use efficiency of maize. Compared with the conventional shallow tillage (RT), STA reduced soil bulk density by an average of 8.18%, increased soil porosity by 11.69%, increased soil water content in 40−80 cm layer by 8.03% and the soil water storage by 8.23%, reduced the water consumption by 6.82%, and increased maize yield by 17.34%, the water use efficiency was thus increased by 31.36%. The soil water storage and water content contributed the highest to the WUE, accounting for 64.59%, 62.89% of the WUE increment, respectively.

Conclusions Full straw returning following by subsoiling could reduce soil bulk density and increase porosity of 0−45 cm layer, thereby enhance soil water reservoir, and increase maize water use efficiency and yield. Full straw returning following by subsoiling is regarded as an ideal tillage method for high maize yield and efficient use of water resources in the Xiliao River Plain irrigation areas.