Phenological Changes of Soybean in Response to Climate Conditions in Frigid Region in China over the Past Decades

Abstract

Plant phenology becoming a focus of current research worldwide is a sensitive indicator of global climate change. To understand observed soybean phenology and explore its climatic determinants in frigid region (Northeast China and northeast in Inner Mongolia), we studied the phenological changes of soybean [Glycine max (L.) Merr.] for the frigid region during 1981–2017, then analyzed the contribution of major causal climate factors to phenology based on multiple stepwise regression. Altogether, the average temperature from sowing to maturity (WGP) was significant increasing, accumulated precipitation and sunshine hours were decreasing. More than 50% of observations showed delays in sowing, emergence and maturity stage and short durations of sowing to flowering (VGP), flowering to maturity (RGP) and sowing to maturity (WGP). The late sowing was getting the following phenological timing backward, but the flowering and maturity delaying trends were much less than that of sowing timing due to the warming accelerated growth of soybean. Detailed analysis indicated mean temperature and accumulated precipitation of the 1–3 months immediately preceding the mean emergence, flowering and maturity dates influenced the phenological timing in higher latitude areas (HLJ and FL), while in JL and LN, accumulated precipitation and sunshine hours(replacing mean temperature) were the climatic determinants. These results brought light the importance of research and policy to support strategies for adaptation to local condition under the climate change.

Trends and Climate Response in the Phenology of Crops in Northeast China

“…Generally, climate factors such as temperature, precipitation and sunshine hours are the important determinants of crop growth and development (Bai and Xiao, 2020). During the past few decades, the climate change during the growth period of three crops across the NEC was mainly manifested in the increase in temperature and sunshine hours, and the decrease in precipitation (Li et al, 2011;Liu et al, 2013;Gong et al, 2021). Clarifying how these climate variables influence crop phenology is of paramount importance in understanding and implementing adaptation strategies to climate change (Tao et al, 2013;Bai et al, 2019;Liu et al, 2021).…”

“…In contrast, the lengths of growth period of the three crops at most stations were positively correlated with accumulated precipitation (AP) and accumulated sunshine hours (AS) during the corresponding growth period. The main reason is that low precipitation may increase the occurrence of drought events, leading to early senescence of crop leaves and earlier phenology (Blum, 1996;Li et al, 2021), and sunshine hours have an important influence on the photoperiod of crops (Zhang and Tao, 2013). Furthermore, we investigated the correlations between the lengths of crop growth period and SD.…”

“…Related studies pointed out that delaying sowing dates and applying the longer-duration cultivar were management adaptations used by farmers to adapt to climate change occurring in the past few decades, and that can continue to be used (Wang et al, 2013;Tao et al, 2014a;Zhao et al, 2015;Wang et al, 2017a;Xiao et al, 2017;Xiao et al, 2019;Ye et al, 2019). With the climate warming, the potential growing season has lengthened, and the risk of low-temperature freezes and frost injury has decreased in NEC (Gong et al, 2021). Local crop producers could choose longer growing season crop cultivars to take advantage of the increasing temperatures, as a longer crop growing season would make the efficient use of thermal resources (Wang et al, 2017a).…”

“…The impacts of climate variability and/or climate change on crop phenology have been studied by numerous researchers in China for various crops, such as maize (Tao et al, 2014a;Xiao et al, 2016;Xiao et al, 2019;Liu et al, 2021), rice (Tao et al, 2013;Wang et al, 2017a;Bai et al, 2019;Ye et al, 2019;Bai and Xiao, 2020), wheat (Wang et al, 2013;He et al, 2015;Xiao et al, 2015;Xiao et al, 2017), soybean (He et al, 2020;Gong et al, 2021), and cotton (Wang et al, 2017b;Li et al, 2021a). As climate warming accelerates the crop growth and shortens the growing period (Tao et al, 2014a;Xiao et al, 2015), previous related studies have mainly focused on the effects of increasing temperature on crop phenology (Estrella et al, 2007;.…”

“…In NEC, maize, rice and soybean were the three most important crops, and the planting areas of maize, rice and soybean in 2015 were 1.42 × 10 7 (51.1%), 5.82 × 10 6 (20.9%) and 3.75 × 10 6 ha (13.5%), respectively (Yan et al, 2020). Due to climate change, the phenology of maize (Li et al, 2014), rice (Gao et al, 2018) and soybean (Gong et al, 2021) in NEC have all undergone significant changes, but there is still a lack of comparative studies on the phenology of the three crops in response to climate change (Li et al, 2011;Zhao et al, 2015). In order to deeply understand the processes and mechanisms controlling various crop responses to ongoing climate change, it is important to investigate phenology shifts of main crops in NEC in response to climate change over the past few decades.…”