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Incorporating returned straw with tillage practices during the fallow period may be crucial for yield increase of dryland maize (Zea mays L.) by improving soil water storage. Field experiments were conducted over 3 yr (2016)(2017)(2018)(2019) to investigate the effects of four treatments (CK, no-till with crushed straw left on the ground; RT, rotary tillage with crushed straw mixed into the 0-to-20-cm soil layer; DP, deep ploughing with crushed straw mixed into the 30-to-35-cm soil layer; SM, no-till with whole straw mulched on the surface) on soil water storage, yield and its components, and water use efficiency (WUE) of dryland maize in northern China. Compared with CK, the yield of RT, DP, and SM treatments increased by 2.3 to 68.3, 22.8 to 126.1% and 9.3 to 119.8%, respectively, during the 3 yr. The most significant increase was obtained in the drier year of 2019, though yields were lowest overall that year. The DP treatment had greater water storage in the upper soil layer (0-100 cm) in all 3 yr, followed by SM and RT. The average increment of precipitation use efficiency and WUE under RT, DP, and SM was 25.4, 58.6, and 48.6 and 20.7, 31.6, and 29.9%, respectively. The results indicated that numerically higher yield components and yields of dryland maize were observed upon DP and SM. Thus, these two practices (DP and SM) could be suitable field management choices to promote water storage and production of dryland maize in the northern China.Abbreviations: CK, control; no till with crushed maize straw left on the ground; DP, deep ploughing with crushed maize mixed into the 30-to-35-cm soil layer; ET, evapotranspiration; PUE, precipitation use efficiency; RT, rotary tillage with crushed amazed mixed into the 0-to-20-cm soil layer; SM, no-till with whole maize straw mulched on the surface; WUE, water use efficiency.

Amis Additional tillage practices such as subsoiling (SS) and deep tillage (DT) during fallow period are beneficial to water storage and yield increases in dryland wheat fields compared with no tillage (NT). However, soil chemical characteristics responses to tillage practices that change within growth seasons are less understood. Methods This study evaluated the effects of three tillage practices (NT, SS and DT) on soil organic carbon (SOC), total nitrogen (TN), available nutrient and its relations with yield. Soil samples from five experimental years were analyzed to determine the contents of SOC, TN, and available nutrients. Soil samples from the fifth experimental year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions. Results The SS and DP treatments favored grain yield, straw yield and straw carbon return compared to NT. In the whole profile (0–40 cm), the mean annual SOC stock and sequestration rate were 62.3, 59.4 and 38.5 t ha− 1 and + 0.73, + 0.59 and − 8.27 t ha− 1 yr− 1 under NT, SS and DT. The mean annual TN stock and sequestration rate were 5.45, 6.18 and 5.95 t ha− 1 and + 0.28, + 0.53 and + 0.67 t ha− 1 yr− 1 under NT, SS and DT. Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions. Similarly, soil available nutrients improved under NT and SS at 0–20 cm soil layer. Conclusions This result indicated that SS was an excellent practice for increasing wheat productivity, SOC, TN and nutrient availability synergistically in dryland wheat fields in North China.