Analyzing effects of different substrates (maize stalks, cotton husks and wheat straw) on performance of oyster mushroom (pleurotus ostreatus) in Zimbabwe

Abstract

There is a lot of lignocelluloses agricultural waste being burnt in farms posing a lot of threat to biodiversity and the environment. Mushroom farming can prove to be the way to go since it's production can recycle agricultural waste and produce nutritious mushrooms that can improve human diet. Malnutrition is becoming a perennial problem especially in developing countries. The main objective of the project was to analyze the effects of maize stalks, cotton husks and what straw on performance of oyster mushroom (Pleurotus ostreatus) since the effect of these substrates is not well documented for Zimbabwean conditions. Randomized complete block design was used to analyze the effects of three substrates on the performance of oyster mushroom. The three treatments were cotton husks, wheat straw and maize stalks. The trial was replicated three times. Kits placement was used as blocking factor. The substrate type have an effect on stipe length (p<0.05). Cotton husks gave the longest stipe length (4.55cm). Substrate type also have an effect on cap diameter (p<0.05). Oyster mushroom from cotton husk gave the widest cap diameter (9.25cm). Substrate type had no significant effect on total yield (p>0.05). The type of substrate had an effect on all nutritional status parameters (p<0,05). The type of substrate had an effect on energy (p<0.05), with wheat straw providing the highest energy (29.74calorie/100g). The effect of substrate was seen on protein content (p<0.05). Wheat straw had the highest protein content of 2.66g/100g. There was significant difference in means for fat produced from different substrates (p<0.05). Wheat straw produced oyster with highest fat (1.59g/100g). Effect of substrate was observed on fibre content (p<0.05) with wheat straw producing more fibre (3.41g/100g). The effects of substrate type was also observed zinc and iron (p<0.05) with wheat straw giving the highest Zn and Fe (9.42mg/100g and 19.49mg/100g respectively). Carbohydrate was affected by substrate type (p<0.05) with maize stalks giving the highest content (1.32g/100g). Substrate type affected moisture content (p<0.05). Cotton husks had the highest moisture content of 91.91%. As a conclusion, oyster grown from cotton husks performs best in terms of growth and yield but oyster from wheat straw is more nutritious. It is recommended to grow oyster from wheat straw as it has more nutrients. However it can also be recommended to blend main substrates with supplements to realize higher growth performance, improved yield and highly nutritious oyster mushroom. Keywords: Pleurotus Ostreatus, stipe length, cap diameter, total yield and nutritional composition