Differential growth and productivity of oyster mushroom ( Pleurotus pulmonarius ) on agro-waste substrates in semi-arid regions of Kenya

Authors

• Judy Wanjira Wachira * ¹
• Simon Nguluu ¹
• Josphert Kimatu ²

1. School of Agriculture and Veterinary Sciences, South Eastern Kenya University, Kitui, Kenya
2. School of Pure and Applied Sciences, Department of Life Sciences, South Eastern Kenya University, Kitui, Kenya

Abstract

Purpose Food insecurity and poverty are common challenges in arid and semi-arid regions.  Diversification into low input agriculture like mushroom cultivation can help address these challenges. However, recommended mushroom substrates in Kenya (rice and wheat straws) are not widely available cheaply. Crop residues found in semi-arid areas can serve as alternative substrates, but their efficiency has not been adequately evaluated. This study evaluated the potential of various agro-waste materials as alternative substrates for cultivation of phoenix oyster mushrooms (Pleurotus pulmonarius) in semi-arid regions.
Method Five agro-waste materials and their combinations were tested: maize stalks, beans straw, maize cobs, rice straw, and Melia volkensii leaves. The study assessed the effects of these substrates on different mushroom growth and productivity parameters. The experiment was set in a randomized complete block design, under relative humidity of 80 – 90% and temperatures of 23 – 24°C, over a 75 day period.
Results Substrates containing M. volkensii failed to colonize fully except in their combination with bean straw, which yielded little. Yields varied significantly by substrate, ranging from 136.2 g/kg of wet substrate in bean straw + Melia volkensii to 434.9 g/kg of wet substrate in rice straw. Mushroom yields from maize stalks + bean straw and maize stalks + maize cobs substrates were not significantly different from those of rice straw, the control substrate.
Conclusion The study showed that combinations of maize stalks, bean straw and maize cobs are suitable alternatives to rice straw, as substrates for oyster mushroom production.

Highlights

• The study showed that Melia volkensii leaves are not a suitable substrate for oyster mushroom production.
• Combining maize cobs with rice straws, maize stalks with maize cobs and maize stalks with bean straw, can hasten the days to mushroom fruiting compared to pure substrates.
• The study further showed that the mean weight, biological efficiency and productivity of oyster mushrooms depend on the substrate type used. The performance of the substrates in terms of yields can be arranged in order of decreasing suitability as follows; rice straw, maize stalks + bean straw, maize stalks + maize cobs, maize cobs, bean straw + maize cobs, maize cobs + rice straw, bean straw, maize stalks + rice straw, bean straw + rice straw, maize stalks and bean straw + volkensii.
• It can therefore be concluded that some of the locally available materials in the semi-arid areas, viz maize stalks, bean straw and maize cobs and their combinations are suitable substrates for oyster mushroom production.

Keywords

• Agro-waste materials
• Biological efficiency
• Oyster mushroom
• Substrates