Optimizing planting dates and cultivars can enhance China's potato yield under 1.5 °C and 2.0 °C global warming

Highlights

• Climate warming increases potato yield in North part China, while decrease in South.

• Adjusting planting date would be effective for rainfed potato under climate warming.

• “Double late” would be optimal to cope with climate warming for rainfed potato.

• Optimal combination of PD and cultivar for irrigated potato would vary across China.

• The yield would increase 2.6–65.2% under climate warming with optimal combination.

Abstract

Rising temperatures and varying precipitation patterns pose huge challenges to the global potato supply. Understanding the adaptation potential of potato to climate change is urgently needed to help develop effective measures for future agriculture and food security. In this study, we evaluated future potato yield changes under 1.5 °C and 2.0 °C warming scenarios, and explored potential adaptation strategies by optimizing planting dates (PD) and cultivars across China's potato production regions. Compared with the baseline period (1986–2015), potato yields would increase in North single (NS) and Central double (CD) cropping system zones, but would decrease in South winter (SW) and Southwest mixed (SWM) cropping system zones under the 1.5 °C warming scenario without considering adaptation measures. Under the 2.0 °C warming scenario, potato yield would increase across China's potato planting zones except for SWM. Adjusting PD would be more effective for increasing rainfed potato yield across China than changing cultivars under the two warming scenarios. Overall, late PD coupled with a late-maturing cultivar would be the optimal selection for rainfed potato production. For irrigated potato, adjusting PD would be more effective than changing cultivars in NS and SW, but the opposite would be true in CD. The optimization of a single measure would have little impact on yield in SWM. The optimum PD would be early PD in NS and late PD in SW and SWM. The optimum cultivar would be late-maturing in NS, CD, and SWM, and middle-maturing in SW. Under the optimal combination, rainfed and irrigated potato yield would increase by 3.4–44.2% and 2.6–49.3%, respectively, under the 1.5 °C warming scenario, and would increase by 7.1–51.6% and 8.5–65.2%, respectively, under the 2.0 °C warming scenario. Our study results provide valuable information for policymakers and stakeholders involved in potato production to aid in planning agricultural strategies to safeguard potato production.

Introduction

Global climate change, especially increasing temperature, puts a huge strain on agriculture (IPCC, 2014). Generally, rising temperatures will shorten the growing period and decrease carbohydrate accumulation by crops (Adavi et al., 2018). Therefore, the 2015 Paris Agreement aimed to constrain rises in global average temperature to below 2 °C above the pre-industrial levels (1861–1880), with an ideal increase of less than 1.5 °C (UNFCCC, 2015). Developing global warming mitigation measures for crops is needed to ensure the stability and security of food production (Gregory and Marshall, 2012).

Potato (Solanum tuberosum L.) is the fourth most important food crop (after wheat (Triticum aestivum L.), rice (Oryza sativa L.), and maize (Zea mays L.)) in terms of human consumption (FAO, 2016). China has been the world's leading potato producer since 1993, and it produces 9.6 × 10⁷ Mg of fresh potato per year, accounting for 25.1% of the world's total production and 29.6% of the total planted area of potato in the world (Tang et al., 2019). Due to the variation of climate conditions and agronomic options among the different potato planting zones in China, there are four potato planting agro-ecological zones. Annual potato yield varies remarkably from 4 to 33 Mg ha⁻¹ across China, and the variation of potato yield was highest in the North single cropping system zone (Teng et al., 1989; Jansky et al., 2009; Yang et al., 2018).

Potato has good performance under cool and frost-free seasons, and poorer performance under hot conditions (Tang et al., 2020). To some extent, increasing temperatures lead to decrease potato yields (Muthoni and Kabira, 2015). Increasing temperatures also increase the water requirement, and together with changing rainfall patterns, drought stress risks for potato are greater (Schafleitner et al., 2011). The mean annual temperature in China has increased by 1.2 °C since the 1960s (Piao et al., 2010), and for regions with cold spring and summer seasons, rising temperatures could extend the potato planting window, and therefore more planting dates and cultivars could be selected, which would be beneficial for potato production (Adavi et al., 2018; Tang et al., 2018a). However, in warmer regions of China, such as the south winter mixture cropping system zone, increased temperature is the main obstacle to guaranteeing the supply of potato due to its negative impacts on potato production (Haverkort, 1989; Haverkort and Struik, 2015).

Changing climate could have positive impacts on crops if effective adaptation measures are developed and used (Adavi et al., 2018). Many studies have been conducted to explore the impacts of climate change adaptation options on potato yield. Some studies have found that adjusting planting date and selecting suitable cultivars were two cost-effective adaptation management options (Pulatov et al., 2015; Korres et al., 2016). Adjusting planting date could help reduce the occurrence of climate stresses, including heat stress and drought stress during critical growth stages under global warming conditions (Wang et al., 2015; Tang et al., 2018a, Tang et al., 2018b). Generally, rising temperatures shorten the potato growth period by accelerating the development rate, while the use of late-maturing cultivars could offset the effect of high development rates (Muthoni and Kabira, 2015). Thus, a large number of studies have investigated the optimization of planting date and cultivar selection to propose climate change adaptation strategies (Korres et al., 2016; Adavi et al., 2018; Tang et al., 2018a).

In the future, temperature is projected to further increase (Harrison et al., 2014). Thus, the impacts of climate warming on potato production will continue, and assessments of these impacts have been explored globally (Hijmans, 2003; Raymundo et al., 2018). On a global scale, potato yield without adaptation measures would decrease by 18–32% under a temperature increase of 1.6–3.0 °C (Hijmans, 2003). However, the impacts of global warming on potato production would be different in different regions. In England and Wales, the area of land that is currently well suited for rainfed potato production would decrease by 88% and 74%, respectively, by the 2050s under future climate warming (Daccache et al., 2011). In Isfahan Province of Iran, potato yield reduction would vary from 11.2% to 30.6% under different scenarios of future climate change (Adavi et al., 2018). For a tropical Andes location, potato production would decrease by 87–97% under future global warming (Tito et al., 2017). In China, future climate change would decrease potato yield by 30–50% and 34.6–40.0% in Northwest China and South China, respectively (E et al., 2011; Liao et al., 2017). Although some studies have investigated the impacts of future climate change on potato production, most of these studies were concentrated on limited sites. Furthermore, the response of potato production to 1.5 °C and 2.0 °C warming scenarios in China has not been reported.

The adaptation strategies for potato production under future climate change could be very different in different planting zones across China due to contrasting climate conditions and cropping systems. Further, the contributions of optimizing planting date and adjusting cultivars used in actual production should be identified to determine the adaptation mechanism of potato production to future warming of 1.5 and 2.0 °C. Determining the adaptation potential of potato to changing climate and the adaptation mechanism could help to develop effective production measures and to optimize potato planting layouts in China. Therefore, the objectives of this study were to: (1) determine the response of potato yield to future global warming of 1.5 °C and 2.0 °C, (2) determine the optimal combination of PD and cultivar under 1.5 °C and 2.0 °C warming scenarios in different potato planting regions in China.