Effects of Nitrogen, Phosphorus and Potassium Levels on Kenaf (Hibiscus cannabinus L.) Growth and Photosynthesis under Nutrient Solution

To date, little is known about the effect of levels of nitrogen, phosphorus and potassium on kenaf grown innutrient solution culture. The objective of the present study was to examine the effects of different nitrogen,phosphorus and potassium levels on kenaf growth such as diameter, plant height, leaf number, root dry weight,stem dry weight and leaf dry weight and physiology like chlorophyll content, photosynthesis and stomatalconductance. Treatment consisted of 5 different levels of nitrogen viz. 0, 50, 100, 200 and 400 mg/L and 5different levels of phosphorus and potassium viz. 0, 25, 50, 100 and 200 mg/L replicated thrice in a completelyrandomized design in a shade house. Growth (diameter, plant height and leaf number), chlorophyll content andphotosynthesis were measured once weekly and plant components biomass was measured, 28 DAT. Differentlevels of nitrogen, phosphorus and potassium had significant effects on all the parameters studied. The highestvalues for diameter, plant height, leaf number, root dry weight, stem dry weight, leaf dry weight, photosynthesisand stomatal conductance were obtained from 200N, 100P and 100K whereas values decreased with furtherincrease in levels of nutrient concentration. All the growth rates, chlorophyll content and photosynthesis declinedwith lower level of nitrogen, phosphorus and potassium. Among the plant components, leaf dry weight had thegreatest decrease while root/shoot ratio increased under N deficiency. The results of this study provide newknowledge to produce kenaf with better nutrient management in the field.