Nutrient management for cut flower roses under rain shelter

Abstract

Rose (Rosa spp.) is the top-ranking and largest traded cut flower in the world and it is saluted as the queen of flowers due to its majestic fragrance brilliant colours, attractive shape, varying size, and excellent keeping quality. A balanced supply of nutrients ensures maximization of productivity and quality. Therefore, an efficient and judicious use of fertilizers along with micronutrient application is essential for attaining higher yield per unit area. However, a nutrient management schedule for roes under Kerala conditions is not yet standardized. Hence the present study entitled “Nutrient management for cut flower roses under rain shelter” was carried out in the Department of Floriculture and Landscaping, College of Horticulture, Vellanikkara during 2021-2023. The objective of the study was to assess of response of the rose variety Taj Mahal to different levels of NPK and foliar supplements for commercial production of cut roses in agro-climatic conditions of Kerala. The experiment consisted of 13 treatments, which included different combinations of 3 doses of fertilizers viz; 4:1.5:5 N: P2O5: K2O g/plant/year, 8:3:10 N: P2O5: K2O g/plant/year and 12:4.5:15 N: P2O5:K2O g/plant/year and three levels each of foliar supplements viz; BA 200 ppm, 2% seaweed extract, 0.5% Sampoorana KAU vegetable multimix and control (without fertilizers and FYM). Six months old grafts of the rose variety ‘Taj Mahal’ were used for the study. Observations on vegetative characters, floral characters, post-harvest aspects as well as nutrient status of the growing media and plant nutrient uptake were recorded. Throughout the observation period, different doses of fertilizers, foliar supplements, and the interactions between fertilizers and foliar supplements had a significant impact on vegetative characteristics. Among the fertilizer treatments, plant height was significantly highest in A3 (12: 4.5: 15 N: P2O5: K2O) (55.94 cm) at 10 MAP. Application of 0.5% Sampoorna (54.58 cm) and BA 200 ppm (53.02 cm) resulted in the highest plant height at 10 MAP. Application of fertilizers and foliar sprays significantly influenced plant spread. The fertilizer treatments A3 (12: 4.5: 15 N: P2O5: K2O) (27.95 cm) and A1 (4: 1.5: 5 N: P2O5: K2O) (26.96 cm) recorded the highest plant spread at 10 MAP. Among the foliar supplements, B4 (0.5% Sampoorna) (27.71 cm) and B2 (BA at 200 ppm) (27.54 cm) were superior compared to other treatments at 10 MAP. Different levels of fertilizer had no significant effect on the number of branches per plant throughout the experiment. The maximum number of branches were produced by B2 (BA 200 ppm) at 8 MAP (3.37) which was on par with B3 (2% seaweed extract) (3.1), and B4 (0.5% Sampoorna) (3.08). A3 (12: 4.5: 15 N: P2O5: K2O) produced more number of leaves per branch (8.2) which was on par with A2 (8:3:10 N: P2O5: K2O) (8.07) at 10 MAP. Among the foliar supplements, BA 200 ppm produced the maximum leaves per branch (8.34) which was on par with B3 (8.05) and B4 (8.03) during the same period. The treatment combination of A3 x B2 (12:4.5:15 N: P2O5: K2O and BA 200 ppm) was however found to record increased plant height, plant spread and number of leaves per branch throughout the observation period. A3 x B4 (12:4.5:15 N: P2O5:K2O and 0.5% Sampoorna) was found to be superior with regard to number of branches per plant. The floral characters were significantly influenced by different doses of fertilizers. Among the floral characters, the least number of days taken for flower bud initiation was recorded in A3 (12: 4.5: 15 N: P2O5: K2O) (21.95 days), and the least number days taken from bud initiation to commercial stage of harvest was in A3 (12: 4.5: 15 N: P2O5: K2O) (13.37 days) which was on par with A2 (8:3:10 N: P2O5: K2O) (13.69). The highest flower bud circumference was recorded in A3 (12: 4.5: 15 N: P2O5: K2O) (3.75 cm). The longest neck length was found in A3 (12: 4.5: 15 N: P2O5: K2O) (3.94 cm) which was on par with A2 (8:3:10 N: P2O5: K2O). The longest stalk length was recorded in A3 (12: 4.5: 15 N: P2O5: K2O) (28.16 cm). The highest neck girth (0.29 cm), and stalk girth (0.32 cm) were observed in fertilizer treatment A3 (12: 4.5: 15 N: P2O5: K2O) which was on par with A2 (8:3:10 N: P2O5: K2O) (0.29 and 0.32 cm respectively). However, the number of flowers per plant and the length of flower bud were not significantly influenced by the different doses of fertilizers. Foliar supplements also significantly influenced the floral characters. Among the floral characters, the least number of days taken for flower bud initiation (21.24 days), the least number of days taken from bud initiation to commercial stage of harvest (12.90 days), the maximum circumference of flower bud (3.67 cm), and the highest stalk length of flower (28.4 cm) was recorded in BA 200 ppm. The highest number of flowers per plant (40.38) and neck length (4.1 cm) was however recorded in 2% seaweed extract which was on par with BA 200 ppm. The length of flower bud was also the highest (1.8 cm) in 2% seaweed extract. In terms of days taken for flower bud initiation (20.67 days), days taken from bud initiation to commercial stage of harvest (12.45 days), flower bud circumference (3.96 cm), number of flowers per plant (40.53), neck length (4.33 cm), neck girth (0.31 cm), stalk length (32.36 cm) and stalk girth (0.33), the treatment combination of 12:4.5:15 N: P2O5: K2O and BA 200 ppm produced better results. The treatment combination of 8:3:10 N: P2O5: K2O and BA 200 ppm was observed to produce the maximum vase life and total water uptake (7.37 and 25.63 days respectively). The pH, EC, organic carbon, and available N, P, and K in the growing media were all analyzed both before and after the experiment. The pH in T9 (12: 4.5: 15 N: P2O5: K2O and 2% Seaweed extract) and T12 (8:3:10 N: P2O5: K2O and 0.5 % Sampoorna) was reduced after the experiment (5.18). T5 (8:3:10 N: P2O5: K2O and BA 200 ppm) and T7 (4: 1.5: 5 N: P2O5: K2O and 2% seaweed extract) (0.13 dS/m) had the lowest EC after the experiment. T6 (12:4.5:15 N: P2O5: K2O and BA 200 ppm) recorded the highest available K (872.04a kg/ha), and available P (590.93 kg/ha) whereas T12 (12:4.5:15 N: P2O5: K2O with 0.5% Sampoorna) recorded the highest available N (677.38 kg/ha). T1 (4:1.5:5 N: P2O5: K2O), T6 (12:4.5:15 N: P2O5: K2O and BA 200 ppm), and T12 (12:4.5:15 N: P2O5: K2O and 0.5% Sampoorna) resulted in higher plant nitrogen (1.88%), potassium (1.01%), and phosphorous (1.84%), contents respectively. T6 (12:4.5:15 N: P2O5: K2O and BA 200 ppm) treatment resulted in the highest plant uptake (N, P, and K) (0.73, 0.8, and 0.4 g/plant). From the results of the present study it can be concluded that the treatment combination A3 x B2 (12:4.5:15 N: P2O5: K2O and BA 200 ppm) of resulted in better plant height, plant spread, and number of leaves per branch, days taken for flower bud initiation, days taken from bud initiation to commercial stage of harvest, flower bud circumference, number of flowers per plant, neck length, neck girth, stalk length, stalk girth water uptake and vase life. Thus for commercial rose cultivation in Kerala under protected conditions, a combination of fertilizer dose of 12:4.5:15 N: P2O5:K2O g/plant/year as 3 split doses and BA 200 ppm application at fortnight intervals can be suggested.