Assessment of agriwaste derived substrates to grow ornamental plants for constructed wetland.

Burning of surplus residues in agricultural fields is a common practice in many countries of the world. This practice adds emissions into the atmosphere and results in the loss of essential plant nutrients, hence, there is a need for developing technologies for the sustainable management of agri-residues. Constructed wetlands offer excellent nature-based, low-cost green technologies for the treatment of wastewater using surplus agricultural residues as wetland substrates to grow ornamental plants as a source of income. This study was conducted to investigate the use of agricultural residues and biochar as substrates to grow ornamental plants in constructed wetlands. Four ornamental plants (Canna Indica, Gerbera jamesonii, Liliumwallichianum, and Tagetes erecta) were grown in six different substrate combinations for 120 days. Data on plant growth parameters were collected for each plant and compared to select the best substrate combination. Canna Indica and Lilium wallichianum resulted in significantly higher growth and nutrient uptake (P<0.001) with the substrate of 15% rice straw, 80% soil, 5% biochar (T4), and 25% sugarcane bagasse, 70% soil, 5% biochar (T5) compared to other plants. The result concluded that agricultural waste-derived substrates are viable alternatives having fertilizing effects with the potential for nutrient recovery. The present study provides an alternative approach to utilize agricultural waste sustainably to grow ornamental plants in the constructed wetland which reduces the overall cost of the wetland unit making it more cost-efficient.