Yield Response of Pigeonpea to Staggered Sowing Dates Under Rainfed Conditions in the Deccan Plateau

Abstract

Pigeonpea (Cajanus cajan) is a deep-rooted, long-season legume grown on rainfed farms across the Deccan Plateau, and sowing date is one of the few management levers a smallholder can pull without buying anything. Advice on when to sow is nevertheless inconsistent, and field reports that compare staggered sowings often disagree. This narrative review asks why. It draws on published work on pigeonpea phenology and its response to photoperiod and temperature, on the general literature on planting date and crop yield, on monsoon variability in peninsular India, and on the biology of the main insect pest and diseases, and it reports no new data. The central difficulty is that the response to sowing date is not a property of the crop alone. It depends on the genotype and its photoperiod sensitivity, on how rainfall happens to fall in a given season, and on pod borer pressure, which shifts with the timing of flowering and with what else is flowering nearby. Because most field series are short, spanning few seasons and few sites, these effects are hard to separate from one another and from chance. We organise the evidence around a simple appraisal framework, explain why reported optima rarely transfer, and set out what a sowing-date series would need to record to be useful beyond the season in which it was run.