This study details the nutrient demands of Cannabis sativa in controlled environments. The research aimed to identify deficiency symptoms for rapid detection and correction by cultivators, thereby minimizing yield and quality losses.
Cannabis plants were grown with specific nutrients withheld (N, P, K, Ca, Mg, S, Fe, Mn) and compared to control plants receiving a complete nutrient recipe. The experiment started at the change to a 12/12-hour light/dark photoperiod and continued until commercial maturity.
The study focused on daily monitoring of plants, documenting the development and progression of visual deficiency symptoms, and taking weekly photographs. Nutrient element concentrations were analyzed in both upper and lower canopy foliage at the onset of visual symptoms. At harvest, plants were evaluated for biomass partitioning and cannabinoid composition in inflorescence tissues.
Key findings include:
Substantial reductions in vegetative growth and inflorescence yield due to individual nutrient deficiencies.
Deficiencies in nitrogen and phosphorus resulted in the most significant reductions in aboveground vegetative fresh weights.
Except for iron and manganese deficiencies, all other nutrient deficiencies led to a 33% to 72% reduction in floral yields compared to the control.
Minor effects on secondary metabolite composition.
Discrepancies between the onset of visual deficiency symptoms and elemental analyses of foliar tissues.
The study concludes that cultivators should use an integrated approach to diagnose nutrient deficiencies and implement timely corrective actions to ensure optimal productivity and minimize impacts on yield and quality.
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