author(s)
Mrinmoy Samadder, Prianka Howlader and Santosh Kumar Bose

abstract
A field experiment was conducted at the Research Farm of Patuakhali Science and Technology University (PSTU), Dumki, Patuakhali during the period from November 2022 to February 2023 to investigate the growth, yield and economic return of cauliflower as influenced by different sources of manures and chitosan oligosaccharides (COS). The two factors experiment was carried out with two sets of treatment consisting of four different manures (M0=Control; M1= Cowdung @ 10 t/ha; M2=Vermicompost @ 1.5 t/ha; M3= Mustard oil cake @ 2 t/ha and three different concentrations of COS (T0=Control; T1= COS @ 50 mg/L and T2=COS @ 100 mg/L). The experiment was carried out in Randomized Complete Block Design with three replications. Manures and different concentration of COS and their treatment combinations showed significant difference in respect of all growth and yield contributing characters of cauliflower. Among the manures, cowdung @ 10 t/ha exhibited best performance and among the COS concentration, COS @ 100 mg/L showed superior performance in case of all growth and yield contributing characters of cauliflower. The treatment combination of cowdung @ 10 t/ha with COS @ 100 mg/L also displayed remarkable performance compared to other treatment combination. The tallest plant (65.26 cm), the longest leaves (64.46 cm) and the tallest stem (14.80 cm) was recorded from the treatment combination of cowdung @ 10 t/ha with COS @ 100 mg/L during harvesting of cauliflower. Similar treatment combination also gave significantly the highest (21.50 cm) diameter of curd, the maximum fresh weight of curd (2.39 kg) per plant, the maximum yield per plot (21.54 kg) and yield (74.81 t/ha). The highest net return (294103.00 Tk./ha) and benefit cost ratio (2.90) were obtained from cowdung 10 t/ha with COS 100 mg/L treatment combination. The finding of this study suggests that cowdung @ 10 t/h with COS @ 100 mg/L foliar application exhibited superior performance and very useful for growth and yield of cauliflower and also profitable for cultivation.