Effect of organic and inorganic fertilizer on growth and yield of Kaentawan (Helianthus tuberosus L.)

Abstract

Kaentawan is a tuber crop and a related species to sunflower. The tubers contain mostly inulin ascarbohydrate reservoir and it is used in a versatility ways such as human food, animal feed, and raw material forhigh fructose syrup and ethanol. The knowledge of its responses to fertilizers under growing conditions in Thailandis limited. The objective of this study was to investigate the effects of cattle manure and chemical fertilizers ongrowth and yield of kaentawan. Treatments consisting of no fertilizer, 1000 kgs of cattle manure, 25 kgs of 12-24-24 chemical fertilizer, 50 kgs of 12-24-12 chemical fertilizer were laid out in a randomized complete block designwith 4 replications. Fertilizers were applied at 15 days after planting (DAP). Data were recorded for SPADchlorophyll meter reading (SCMR), plant height, stem diameter at ground level, stem diameter at middle stem, leafarea (LA), leaf area index (LAI), number of tuber/plant, above ground dry weight, tuber dry weight, total solublesolid index (Brix) of tuber and stem and harvest index at 60, 70 and 90 DAP.

Cattle manure and chemical fertilizer had no effect on SCMR, plant height, Brix, number of tubers/plantand HI. Twenty five and 50 kgs of chemical fertilizer grade 12-24-12 gave the highest stem diameter at ground level(0.63 and 0.53 cm, respectively) at 60 DAP and the highest stem diameter at middle stem at all sampling dates. Thehighest above ground dry weight was also achieved at these rates at 60 DAP (127.7 and 107.0 kg/rai,respectively). Applications of 25, 50 kgs of chemical fertilizer grade 12-24-12 and 1000 kgs of cattle manure yieldedthe highest tuber dry weights of 416.75, 466.80 and 465.7 kg/rai, respectively, at 90 DAP. These treatments alsogave the highest tuber fresh weight of 1637.75, 1913.25 and 1896.75 kg/rai, respectively.