Optimum planting date and cultivar maturity to optimize potato yield and yield stability in North China

Highlights

• APSIM simulated potato growth well under different planting dates and cultivars.

• Late planting could boost potato yield and reduce yield variability in North China.

• Optimal planting date and cultivar maturity depend on precipitation before planting.

Abstract

Potato (Solanum tuberosom L.) is one of most important food crops in North China. Optimizing potato planting date and cultivar maturity is of great importance for increasing yield and reducing yield variability in North China. The APSIM-Potato model was calibrated and validated with field experimental data from a 2-year х 3-planting dates х 3-cultivars study, and used to determine the optimal combinations of planting date and cultivar maturity for rainfed potato production in North China. APSIM-Potato performed well in simulating phenology (mean RMSE = 3.6 days), soil water content in the 0–100 cm soil profile (mean RRMSE = 23.5 %), total dry matter (mean RRMSE = 26 %), and fresh potato yield (mean RRMSE = 22.5 %) under different combinations of planting date and cultivar maturity. Simulated rainfed fresh potato yield in North China was 16,407 ± 6432 kg ha⁻¹. Late planting coupled with middle- to late-maturing cultivars could increase rainfed potato yield in North China. To achieve high yield and yield stability, later planting coupled with early-maturing cultivars is recommended along a ‘N-S’ transect, while a later planting coupled with late-maturing cultivars should be selected along a ‘W-E’ transect. Growth period and growing season precipitation explained 90 % and 85 %, respectively, of the variation in high-stable index of potato yield. Within the potential planting window, the onset of the optimal planting window was negatively correlated with March-May precipitation (R² = 0.82, P < 0.05), and corresponding optimal potato cultivars could be determined based on the onset of the optimal planting window and mean growing season thermal time (R² = 0.92, P < 0.01). Study results determined a simple but feasible rule for farmers to use in selecting the optimal combination of planting date and cultivar maturity to increase rainfed potato yield and yield stability in North China.

Introduction

Potato is the world’s fourth-largest food crop, with global annual total potato yield of 330 Mt (FAO, 2016; Tang et al., 2018a). China is the largest potato producer with almost a quarter of the world’s total yield (Qiu et al., 2016). Potato is mainly planted in North China, and single cropping accounts for 53.9 % and 49.2 % of total planting area and yield, respectively, in China (Tang et al., 2019). However, potato production in this region is severely limited by low and highly variable annual and growing season precipitation (Cabello et al., 2012; Zhao et al., 2014; Tang et al., 2018a, 2018b, 2019; Li et al., 2019). For the rainfed single-cropping system, adjusting planting date and cultivar selection are two effective low-cost options to improve crop yield and reduce yield variability by matching crop demands on the supply of hydrothermal assets (Jansky et al., 2009; Dinah et al., 2018; Tang et al., 2018b; Li et al., 2019).

A large number of field experimental studies have shown that optimal planting date and cultivar maturity vary with regions due to different climate conditions (Wang et al., 2015a; Li et al., 2016; Heltoft et al., 2017; Dong et al., 2018; Tang et al., 2018b). However, even within the same region, there is controversy as to whether early or late planting could achieve greater water use efficiency and yield (Zhao et al., 2005; Shen et al., 2012). Selecting middle- or late-maturing cultivars would improve potato yield if growing season temperature could meet the potato growth requirement (Li et al., 2016, 2019; Tang et al., 2019). However, early-maturing cultivars could achieve higher yield than middle- or late-maturing cultivars under water-stress conditions, especially under terminal drought conditions (Alva et al., 2002; Xie et al., 2012; Dong et al., 2018; Zhang et al., 2018). Few studies have focused on the interaction of planting date and cultivar maturity on rainfed potato yield and yield stability in North China.

Field experiments could help identify the optimal planting date and cultivar maturity (Florio et al., 2014; Yu and Wang, 2015; Li et al., 2016; Tang et al., 2018a). However, field experiments with various planting dates and cultivar maturities at different sites are costly and time-consuming. Moreover, field experimental results with limited sites and years are difficult to be extrapolated to other regions and years due to large differences in climates between regions and years (Jones et al., 2003). Crop models could provide a low-cost way to capture the interactions of different physiological and physical processes and to simulate the responses of crop growth and development to environmental change (He et al., 2017). Therefore, models have been recognized to be effective tools in investigating optimal planting dates of potato in North China (Tang et al., 2018b, 2019). However, these studies did not investigate the interaction of planting date and cultivar maturity on potato yield and yield variability. Therefore, the objectives of this study were to: (1) evaluate the performance of the APSIM-Potato model in simulating the growth and development of potato under different combinations of planting date and cultivar maturity in North China, (2) investigate the interaction of the planting date and cultivar maturity on potato yield and yield variability in North China, and (3) develop a simple and feasible rule to recommend the optimal combinations of planting date and cultivar maturity across North China.