Bt cotton hybrids may require additional supply of fertilizers, due to increased fruit retention in these crops. In 2006, field experiments with various soil applied N, P and K fertilizer combinations, applied according to local practices, were tested in combination with 4 foliar sprays of 2% potassium nitrate, on 18 locations, in 5 districts in Punjab, northern India. Foliar sprays were applied at weekly intervals, starting from flower initiation.
This study showed cotton yield increases of 11% with foliar potassium nitrate sprays (Figure 1), which resulted in a net increased farmer’s income. This yield increase was found to be irrespective of the soil K status and addition of K fertilizer through soil application. Deducting the costs of the foliar fertilizer product from the gross income, resulted in a benefit to cost (B:C) ratio of over 10,4 to 1.
Figure 1. Average effect of soil K and foliar K application in cotton.
Brar, M.S., M.S. Gill, K.S. Sekhon, B.S. Sidhu, P. Sharma and A. Singh. 2008. Effect of soil and foliar application of nutrients on yield and nutrient concentration in BT cotton. J. Res. Punjab Agric Univ 45 (3&4): 126-131.