Quantification of the effects of climate warming and crop management on sugarcane phenology

Crop phenology influences the partitioning of assimilates, crop yield and agronomic management under a changing climate. It is critical to quantify the interaction between climate warming and crop management on sugarcane phenology to understand the adaptation of crop to climate change. Similarly, in crop modeling, parameterizing the phenology of new crop varieties is a major challenge. Historical changes between 1980 and 2014 in spring and autumn sugarcane phenology have been observed in Punjab, Pakistan. Planting, emergence, stalk elongation, peak population and harvest dates advanced by a mean of 2.87, 2.63, 4.47, 5.01 and 6.41 d decade⁻¹, respectively for spring sugarcane, and were delayed by 6.59, 6.21, 4.38, 3.13 and 2.17 d decade⁻¹, respectively for autumn sugarcane. Similarly, planting to stalk elongation, stalk elongation to peak population and peak population to harvesting and planting to harvesting phases were shortened by a mean of 1.60, 0.54, 1.40 and 3.54 d decade⁻¹, respectively for spring sugarcane and 2.21, 1.25, 0.96 and 4.42 d decade⁻¹, respectively for autumn sugarcane. The changes in phenological characteristics of spring and autumn sugarcane were significantly correlated with rising temperature for the period 1980−2014. Application of the CSM-CANEGRO-sugarcane model to simulate sugarcane phenology for a single cultivar at each site across years revealed that simulated phenological characteristics of sugarcane were accelerated with climate warming. We conclude that, during 1980 to 2014, advancement of planting date for spring sugarcane and delay in planting autumn sugarcane, together with adoption by farmers of new cultivars with higher total growing degree-day requirements, have partially mitigated the negative influence of climate-change induced thermal trends on phenological characteristics of spring and autumn sugarcane.