Effects of Surface Mulching on Soil Water Temperature, Physiological Characteristics and Yield of Maize

In order to explore the cultivation techniques for increasing maize yield and water efficient utilization in the semi-arid area of Jilin Province, China, a field experiment was carried out in Taonan City, the semi-arid area of Jilin Province in 2020 and 2021. Common plastic film mulching (CM), degradable plastic film mulching (DM), crushed straw mulching (SM) and no mulching (CK) were set up to study the effects of surface mulching on the temporal and spatial changes of soil water and temperature, physiological characteristics of maize, maize yield and water use efficiency. The results showed that the soil water content was related to rainfall and its spatial and temporal distribution in maize growth stage. The soil water content in 0–60 cm increased with the increase of soil depth in the vertical direction, and the soil water content between treatments was SM > CM > DM > CK. The soil temperature increased first and then decreased with the growth process of maize, and gradually decreased with the deepening of the plough layer. The temperature was increased by plastic film mulching (CM > DM), and decreased by straw mulching. Different water temperature effects caused by surface mulching have different effects on the physiological characteristics, growth and yield of maize, and DM treatment was the best. DM treatment significantly increased the bleeding sap mass and cytokinin content of maize roots due to its coordinated water temperature, significantly reduced the content of soluble sugar and abscisic acid in bleeding sap compared with CK, transmitted the physiological reaction of roots upward through plant hormones and other information substances, indirectly affected the physiological and biochemical processes of shoots, and enhanced the activities of ribulose diphosphate carboxylase, phosphoenolpyruvate carboxylase and glutamine synthetase in leaves, it improved the photosynthetic performance of maize leaves, promoted the growth and development of maize and the accumulation of dry matter in each period, thereby significantly increasing maize yield by 14.13% and water use efficiency by 16.8%. The yield and water use efficiency of maize under CM treatment were 8.59% and 8.1% higher than CK respectively. However, SM treatment resulted in slow accumulation of dry matter, 8.96% yield reduction and 10.4% water use efficiency reduction due to low temperature effect in the early stage, decreased enzyme activity and photosynthetic rate, and slow growth and development. The degradable plastic film mulching can keep water and increase temperature, increase yield and improve efficiency, and reduce environmental pollution, which can provide theoretical basis and technical support for the cultivation technology model of maize yield increase and water efficient use in semi-arid areas.