Abstract
Experiments were conducted at the Field Laboratory of the Department of Environmental Science, Bangladesh Agricultural University, Mymensingh during the period 2016-2017 to evaluate sustainable production of two important medicinal plants- tulsi (Ocimum sanctum) and pudina (Mentha arvensis). The experiments consisted of six treatments viz., To- Control (no fertilizers and manures), T1 - Cowdung, T2 - Mixed fertilizer of NPKS, T3 - Cowdung + NPK fertilizer, T4 - Poultry litter and T5 - Poultry litter + NPK fertilizer. All the growth and yield contributing characters of the selected medicinal plants were influenced significantly due to the application of fertilizers and manures. Effect of fertilizers and manures on sustainable production of tulsi plant, the mixed fertilizer of NPKS application showed significantly the highest effect producing the tallest plant (52.13 cm), maximum branches plant1 (75.46) and the longest leaf length (4.08 cm). But the highest number of leaves plant1 (466.79) as well as the leaf yield (373.43 g plot1) or (1.87 t ha-1) produced in poultry litter + NPK treatment at final harvest (120 DAP). At 78 DAP; the effect of poultry litter + NPK in growing tulsi was also highest in showing maximum branches plant1 (42.47), number of leaves plant1 (509.7) and yield (1.33 t ha-1). But poultry litter treatment produce the highest plant height (47.13 cm) and cowdung + NPK treatment produce longest leaf (4.85 cm) produce in middle stage (78 DAP) of growing. Seed yield maximum in poultry litter + NPK treatment (210 kg ha-1) at final harvest. Effect of fertilizers and manures on sustainable production of pudina plant, cowdung + NPK treated plot showed the highest growth significantly tallest plant (48.63 cm), maximum branches plant1 (63.63), number of leaves plant1 (799.79), maximum leaf length (4.63 cm) and the highest yield (6.4 t ha-1) in growing pudina at final harvest (120 DAP). At 62 DAP, similar effect of poultry litter + NPK was found as maximum branches plant1 (45.04), number of leaves plant1 (306.33) and yield with corresponding values 2.21 t ha-1 respectively. But cowdung + NPK treatment produce the highest plant height (31.42 cm) and poultry litter treatment produce longest leaf (5.78 cm) in middle stage (62 DAP) of growing. The effect of other treatments on the plant traits in tulsi experiment followed the order T5> T1> T4> T3> T2> To and on the plant traits in pudina experiment followed the order T3> T4> T2> T1> T5> To. Overall findings of the present research indicates that the cowdung + NPK contributes greatly in producing the pudina medicinal plants and poultry litter + NPK in tulsi as well as improving the properties of soil which will ultimately be useful to ensure sustainable production of the medicinal plant and their by safer environment. Bio-chemical analysis showed that maximum vitamin-C (65.27 mg 100g1) in tulsi contents were obtained poultry litter treatment. Maximum vitamin-C (41.29 mg 100g-1) in pudina plant and protein contents (20.79%) in tulsi were obtained the poultry litter + NPK treatment. Maximum protein (26.57 %) in pudina contents was obtained the cowdung treatment. Total sugar (%) found in both tulsi (5.00%) and pudina (7.58 %) plant maximum in control (no fertilizers and manures) treatment. Post harvest soil analysis result proved that soil pH and organic matter increased in pudina experimental field and organic matter and exchangeable K increased in tulsi experimental field due to effect of fertilizers and manures treatment.