Soil is an essential natural resource and serves as a medium for the production of food crops for human consumption (Li et al., 2018; Wang et al., 2021); however, overuse and poor management have led to soil degradation, especially in arid and semiarid saline and alkaline soils (Karlen & Rice, 2015). Between 1950 and 2010, soil degradation negatively impacted soil ecosystem services by 60% (Lal, 2015). Hence, only 11% of the world’s soil can be used to grow crops without amendment (Zhang et al., 2020). The world’s population is gradually increasing and is expected to reach 9.6 billion by 2050 (Gerland et al., 2014; Agegnehu et al., 2015). To sustain this rapidly increasing world population, it is vital to improve the soil health to safeguard agricultural production.
In recent years, biochar (BC) has been widely used in soil remediation processes around the globe (Han et al., 2020; Terrer et al., 2021). It has a large specific surface area and strong adsorption properties; furthermore, it can increase soil organic matter contents, remove heavy metal pollutants in soil and increase the crop yield (Akhtar et al., 2014; Baronti et al., 2014; Copper et al., 2020). Long-term application of BC can improve soil fertility and contribute to the sustainability of soil agroecosystems (Jay et al., 2015; Cooper et al., 2020). The application of BC has also been shown to increase peanut yields and improve soil properties in North Queensland, Australia, (Agegnehu et al., 2015) as well as to promote microbial activity and growth in temperate soils (Gomez et al., 2014). Soil moisture is a major parameter in terms of agroecosystems and a material necessity for the growth and development of crops. It affects not only the distribution of life on Earth but also the yields of agricultural crops (Kumari et al., 2014; Deepshikha et al., 2020). Under reduced irrigation conditions, BC has been shown to increase the yield and quality of tomatoes (Akhtar et al., 2014). It can also increase grape yields and the plant available water content (Baronti et al., 2014). Although many studies on improving soil by altering the BC content have been conducted (Zheng et al., 2012; Wong et al., 2017), some studies explored the impact of various rates of BC on salinised soil in arid and semiarid regions, but soil water evaporation depends on internal factors such as soil structure, texture, moisture content, phreatic level, surface characteristics, capillarity and pH; external meteorological conditions, such as temperature, humidity and wind speed, also play a role (Bond & Willis, 1969; Al-Omran et al., 1987; He et al., 2019), for example, BC has been shown to reduce soil evaporation when applied to sandy loam soil (Xu et al., 2016; Ibrahim et al., 2017); however, BC powder added to sandy soil does not reduce water loss through evaporation (Zhang et al., 2016).
Few study combined the indoor soil column simulation and field experiment to cross-check results. It is unclear whether after adding BC the water holding capacity can be maintained throughout the evaporation process during the whole life cycle of maize. It is also unclear what the combined impact of BC addition and soil texture is with regards to soil evaporation. The aim of this study is: (1) How much straw biochar can be applied to effectively slow soil evaporation? (2) How does biochar application increase soil moisture content during different life cycles of maize? (3) What is the mechanism of biochar affecting soil evaporation and water content in soil column experiment and field experiment? Therefore, the research results will help identify the optimal rate, which will play a vital role in reducing soil water evaporation in arid regions.