Potential benefits of promoting snowmelt by artificial snow blacking on the growth of winter wheat and their dependence upon regional climate.

An earlier onset of regrowth after snow disappearance can enable wheat cultivars to avoid the hotter grain-filling period, without the need for early sowing in snowy regions. A blackened snow surface easily accelerates snow melting by absorbing solar radiation. In this study, we compare the yield components associated with snowmelt acceleration over 4 years and in 2 locations (Sapporo, SP, and Memuro, MM) in Japan, which exhibit contrasting autumn and spring climates. Early snow melting by snow-blackening accelerated wheat growth in MM by a maximum of 4 days for heading and 3 days for anthesis. Moreover, accelerating wheat phenological growth improved the grain yield in MM in 2016. This is because wheat plants were less likely to experience the localised cool and rainy weather that typically occurs during anthesis in mid-June. Early anthesis would decrease the likelihood that wheat plants experiencing lower sunlight intensity during the grain-filling period owing to exposure to rainy weather. However, warmer autumn conditions in SP likely hindered the development of high-level cold resistance in overwintering wheat. Accelerating snowmelt is one possible tool for mitigating the fluctuations in regional wheat production; however, the effectiveness of snow-blackening depends on the regional climate.