ALBERT

Description: Soil temperature plays a vital role in determining crop yield. Excessive irrigation may result in low soil temperature and a waste of water resources. In this paper, field experiments were carried out to evaluate the influence of irrigation methods and biochar application on soil temperature. The experiment included six treatments: (a) YB: biochar application in border irrigation with Yellow River water; (b) GB: biochar application in border irrigation with groundwater; (c) DB: biochar application in drip irrigation with groundwater; (d) Y(CK): border irrigation with Yellow River water; (e) G(CK): border irrigation with groundwater; (f) D(CK): drip irrigation with groundwater. The results are as follows: coupling drip irrigation and biochar, soil temperature increased by 1.20–3.87%. In the biochar application in border irrigation with Yellow River water and groundwater, soil temperature increased by 0.80–2.40% and 1.01–5.15%, respectively. Biochar is a medium for reducing the heat exchange of soil and atmosphere, as it hinders bi-directional heat movement. This mechanism was especially apparent at a 0–10 cm soil depth in the treatments of border irrigation using Yellow River water and groundwater. Biochar may help stabilize the fluctuation of soil temperature and improve the soil accumulated temperature. The effect of drip irrigation at 5–10 cm depth, border irrigation using the groundwater and the Yellow River water was great on soil temperatures above the 10 cm level but less on deep soil temperatures. After applying biochar to soil, the soil temperature was more sensitive to external temperature changes, such as air temperature and water temperature. Therefore, in the Hetao irrigation area, applying a proper amount of biochar to farmland soil was shown to improve the water and heat environment and improve the effectiveness of traditional border irrigation in synchronizing water and heat, especially under the drip irrigation condition. The results here suggest that using biochar under drip irrigation can promote growth and increase yield.