Photosynthetic activity and onion growth response to compost and Epsom salt

ABSTRACT

Resource capture and utilization for plant growth and development are largely dependent on plant nutrition. A combination of compost and Epsom salt (MgSO₄·7H₂O) can enhance plant productivity through physiological mechanisms. Information on onion (Allium cepa L.) chlorophyll fluorescence and photosynthetic activity in response to compost and Epsom salt amendments is limited. An experiment was performed to assess onion, cv. Safran, photosynthetic activities and growth of plants established in 0%, 25%, 50%, or 75% w/w municipal solid waste (MSW) compost; and provided with 0, 162.6 and 325.2 mg of Epsom salt in a pot study. An increase in MSW compost up to 50% also increased all chlorophyll fluorescence indices; while leaf production, plant height, and number of fresh scale leaves were increased by 12%, 13%, and 20%, respectively. Bulb diameter and fresh and dry weights were highest in the 25% MSW. An interaction between MSW and Epsom salt was not significant except for total soluble solids content. The 25% MSW compost is adequate for potted onion plant growth and bulb yield while Epsom salt in combination with MSW compost increases onion bulb quality.

KEYWORDS:

• Allium cepa
• compost
• Epsom salt
• organic amendment
• photosynthesis

Acknowledgments

The authors thank Fundy Compost Inc., Brookfield, NS, for donating the MSW compost and Ms. Krista MacLeod for her technical assistance.