A field trial was conducted in Pakistan to study the effect of foliar application of potassium nitrate (KNO3) in comparison to soil incorporated potassium sulphate (K2SO4) on the growth and yield of fine rice “Super Basmati”. The trial was laid out using randomized complete block design with three replicates. The five treatments were: soil application of K2SO4 (70 kg/ha), foliar application of KNO3 at 0,5%, 1,0%, 1,5% and 2,0% on 40 and 60 days after transplanting. Foliar KNO3 sprays at 1,5% and 2,0% increased paddy yield by 5,74% and 10,85% in comparison to that of soil incorporated K2SO4 (Table 1). The increase in yield with foliar sprays is credited to the increase in number of tillers, panicle length, grains per panicle and 1000-grain weight. The 1000-grain weight was statistically significantly higher for the soil applied K2SO4 and the foliar KNO3 at 1,5% and 2,0% compared to the foliar sprays at 0,5% and 1,0% KNO3. There seemed to be a certain threshold value for foliar KNO3 spray solution to have an increasing effect on rice yield. The 1,5% and 2,0% spray solution outperformed the control soil application in terms of paddy yield and farmers’ net income (Table 1 & Figure 1). It is recommended to apply foliar KNO3 at 1,5% and 2,0% solutions on 40 and 60 days after planting rice to increase net returns and enhance paddy yield.
Table 1. Economic analysis of foliar KNO3 application against soil applied K2SO4.
Figure 1. Effect of foliar KNO3 application on the net income of the rice farmer (F=foliar applied, S=soil applied).
Khan, A. W., R.A. Mann, M. Saleem and A. Majeed. 2012. Comparative rice yield and economic advantage of foliar KNO3 over soil applied K2SO4. Pakistan Journal of Agricultural Science, 49(4): 481-484.