Planting Period Effects on Wheat Productivity and Water Footprints: Insights through Adaptive Trials and APSIM Simulations

Scarcity of fresh water and climate change are the two main threats for wheat production in South Asia. Tweaking wheat planting period could be an effective cost-smart strategy to mitigate these stresses. To evaluate the performance of three leading wheat varieties under different planting periods in pragmatic on-farm environments, trials were carried out during 2019–2020 and 2020–2021. Further, to have greater insights on long-term temporal scale, 22 years (2000 to 2021) of crop simulation data were analyzed to identify the optimum planting period of wheat for higher yield and water productivity using the APSIM cropping systems simulation model. The result showed that first fortnight of November (PD1)-sown crop resulted in higher grain yield and more irrigation water use efficiency. Wheat sown during PD1 and in the second fortnight of November (PD2) had 20–25% lower blue water requirement than the second fortnight of December (PD4) crop in the long run. To produce one tonne of wheat grain required an additional 20, 60 and 83 m3 irrigation water when the crop was sown at PD1, PD2, PD3 (first fortnight of December) and PD4, respectively. It was observed that PD4 reduced wheat yields by 20–22% compared to sowing on PD1 and PD2 and every 15 days’ delay in wheat planting after 15 November reduced the length of the crop growing season by 4–5 days. Hence, the early wheat planting is proven superior in harnessing maximum yield with minimum burden on blue water resources.