MSc

The study entitled “Evaluation of biostimulants in growbag culture of organic Amaranthus (Amaranthus tricolor)’’ was conducted in the Department of Vegetable Science, College of Agriculture, Vellayani in order to evaluate the effect of biostimulants under different application methods in growbag cultivation of organic amaranthus.
Amaranthus variety Arun was raised in seed bed and transplanted 21 days after sowing to growbags. Experiments were laid out in CRD with two factors replicated thrice for evaluation of biostimulants and method of application. Foliar application and wick fertigation were the two methods of application under the study for which wick fertigation were installed using pvc pipes and glass wool wicks were used. Biostimulants such as humic acid (3%), humic acid fulvic acid mixture (3%), moringa leaf extract (3%), vermiwash (3%), cow urine (ten times diluted), salicylic acid (50 mgL-1) were compared with RDF (0.22:0.11:0.11 g/plant) and distilled water (control) at weekly intervals.
Humic-fulvic acid mixture @ 3% through foliar application significantly increased the height of plant (85.83 cm), leaf length (15.08 cm) and leaf width (6.80 cm). Vermiwash @ 3% through wick fertigation exhibited the highest number of leaves per plant (118.83). Humic – fulvic acid mixture @ 3% through foliar application was also effective in increasing the branches per plant (11.66) while distilled water through wick fertigation recorded least number of branches per plant (4.66).
Longest root length (34.16 cm) was recorded when humic acid @ 3% were applied through foliar application compared to control (18.66 cm). Late bolting was recorded with humic acid @ 3%, humic-fulvic acid mixture @ 3% and RDF through foliar application. Earlier bolting was recorded in salicylic acid @ 50 mgL-1 through wick fertigation. Application of salicylic acid @ 50 mgL-1 through wick fertigation significantly increased the leaf/stem ratio (0.50) which was at par with vermiwash @ 3% through wick fertigation (0.45).
The total fresh weight of leaves per plant was significantly higher (225.85g) for humic – fulvic acid mixture @ 3% followed by RDF and humic acid @ 3%. At first, second and third harvest, significantly higher yield per cutting was recorded in ten times diluted cowurine (30.64g), RDF (171.62 g), humic – fulvic acid mixture @ 3 % (170.73g) through foliar application respectively while the lowest was recorded by distilled water through wick fertigation. Humic – fulvic acid mixture @ 3% through foliar application also recorded highest yield per plant (646.01 g) compared to distilled water through foliar application (180.72 g).
Humic acid @ 3% through foliar application enhanced vitamin C content (98.20 mg100g-1) while ten times diluted cow urine through wick fertigation recorded the lowest vitamin C (57.14 mg100g-1). Oxalate content was observed low for moringa leaf extract @ 3% through wick fertigation with 0.69 mg. Moringa leaf extract @ 3 % through foliar application enhanced the carotenoid content (7.38 mg100-1g). Ten times diluted cow urine through foliar application produced highest calcium content (3.70 mg100-1g). Biostimulants as well as method of application had no significant effect on stem girth and soil parameters such as soil pH, EC, organic carbon, available nitrogen, phosphorus and potassium.
In conclusion, biostimulants and foliar method of application was found to be effective for improving growth, yield and quality of amaranthus in growbag organic cultivation. Among the biostimulants, humic – fulvic acid mixture @ 3% produced the highest plant height, leaf length, leaf width, branches per plant, fresh weight of leaves, yield and B:C ratio (1.35) compared to control (0.22).