Effect of foliar application of potassium nitrate on late sown wheat (Triticum aestivum L.) in mitigating terminal heat stress

An investigation of on farm trial (OFT) conducted on farmer’s field during Rabi season 2016-17 & 2017-18 in Kishanganj district of Bihar for studies on ‘Effect of foliar application of potassium nitrate on late sown wheat in mitigating terminal heat stress’ revealed that the foliar application of 0.5 % KNO3 at booting and 0.5 % KNO3 at anthesis stage of wheat recorded higher grain yield (31.50 and 30.30 q/ha in 2016-17 and 2017-18 respectively) followed by foliar application of 1.0 % KNO3 only at anthesis stage of wheat (29.75 and 28.50 q/ha in 2016-17 and 2017-18 respectively) in comparison to wheat yield obtained under farmer practice of without any foliar application (28.50 and 25.50 q/ha in 2016-17 and 2017-18 respectively).The two spray of KNO3 0.5% at boot and anthesis stage on wheat showed the favorable effect on yield attributing characters(plant height, effective tillers/m2,spike length, number of grains/spike and test weight). This treatment also recorded higher net return and B:C ratio (Rs. 28,250/ha, 2.49) during 2016-17 and that (Rs. 24,450/ha, 2.27) during 2017-18 respectively. The application of KNO3 at the stage of booting and anthesis stage found effective in increasing the yield of late sown wheat variety HD-2985 in Kishanganj district of Bihar. Farmers were satisfied with the performance of the technology in mitigating heat stress in late sown wheat.