Western disturbances: Occurrence and impact on wheat productivity in Punjab

Western disturbances (WD) bring moderate to heavy rain in the northern parts of the country as well as heavy snow to the mountain areas of the Indian subcontinent. It is the source of most of the winter and post-monsoon rainfall in northwest India. Spatio-temporal analysis of western disturbances was carried out by using weather data recorded at Ballowal Saunkhri (sub-mountainous region), Ludhiana (central plain region) and Bathinda (south west region). The WD events per month were lowest in November and highest in March month averaged over all the agroclimatic regions. The highest numbers of WD events were found during February month in the Sub-mountainous region and during March in central plain region and south-western region. Winter rainfall quantity and number of rainfall events were higher in the sub-mountainous region followed by the central plain region and lowest in the south-western region. Higher number of WD during wheat growing season along with less and well distributed rainfall resulting in lower maximum temperature conditions were conducive for higher productivity in Punjab. The significantly positive correlation was observed between the number of western disturbances and wheat productivity during April month at central plain region and southwest region, whereas, the seasonal total number of WDs showed significant positive relationship at submontane region and southwest region.