Effects of mulch and tillage methods on soil water and temperature as well as corn yield in Hetao irrigation district

Abstract: Soil hydrothermal condition is one of the most important factors affecting crop growth and development in semi-arid areas. In this study, we aimed to investigate effects of different film and tillage technology modes on spring maize yield and soil hydrothermal condition in Hetao Irrigation District. The experiment included four treatments: ridge tillage with full film mulching (LQ), ridge tillage with partial film mulching (LB), flat tillage with full film mulching (PQ) and flat tillage with partial film mulching (PB). The results showed that the soil moisture and soil temperature of LQ were higher (P<0.05) than the LB, PQ and PB treatments in the whole growing stage in 2014 and 2015. The suitable soil thermal conditions in LQ made plant grow vigorously, and it consumed large amount of soil water to enhance biomass and leaf area accumulation. In addition, the full film mulching was more effective at enhancing component factors influencing yield and reserving water in soil profile than partial film mulching, which resulted in higher yield and water use efficiency (WUE). There was an inverse correlation between soil temperature and soil moisture in arable layer. With the increasing of temperature and crop water consumption during growing period, LQ showed significant effect on soil water conservation. In 2014 and 2015, the soil temperature was higher (P<0.05) in LQ than in other treatments while the lowest value was recorded in the PB treatment. However, the soil temperature in LB was higher (P<0.05) than in PQ in 2014; it was opposite that higher soil temperature was recorded in PQ compared with LB in 2015. It implied that tillage technology had a significant influence on average temperature compared with mulching mode under drought conditions in 2014. Conversely, mulching mode played an more important role in preserving thermal conditions than tillage technology during the humid year in 2015. Overall, ridge tillage efficiently transferred and accumulated heat from shallow soil layer to deeper layers. Additionally, the higher the soil surface temperature, the more significant the film insulation effect. LQ can not only enhance the number of rows per ear and grain number, but also were conducive to the accumulation of dry biomass, promote the formation of maize yield under drip irrigation, and increase water use efficiency. LQ efficiently promoted water infiltration and regulated the surface temperature resulting in soil moisture conservation and evaporation inhibition. These effects were much clearer and more consistent with ridge tillage. In addition, full plastic film mulch had an insulation effect compared with partial plastic film mulch, and thus thermal energy could be effectively transferred and stored at the tillage layer where it was essential for maize growth. This study could provide a theoretical basis for improving soil hydrothermal conditions in Hetao Irrigation District and thus enhance crop productivity and quality.