Impact of cultural practices on trichoderma strains in papaya rhizosphere, diamare division, Cameroon

Organic farming is a method of agricultural production that aims to respect natural systems and cycles, maintain and improve the condition of soil, water, and air, and the health of plants and animals. It is an answer to the environmental sufferings caused by chemical pesticides and synthetic fertilizers. Microscopic soil fungi in the genus Trichoderma are important in agricultural contexts as they induce soil fertility and plant resistance to pathogens. The present work assesses the presence of Trichoderma spp. in soil samples from the papaya rhizosphere in the Sudano-Sahelian area of Cameroon. Cultural practices were recorded in papaya orchards through semi-structured interviews addressed to papaya growers identified in this region. Ten papaya trees were randomly selected for soil samples in four treated plots. Three samples of soil were collected around each labelled papaya tree at 25, 50, and 75 cm from the trunk for a depth of up to 40 cm, and a composite sample consisting of the mixture of the resulting 30 soil samples performed per plot was obtained and kept for further analysis. Moreover, an additional composite soil sample from experimental papaya in the organic experimental farming site of Meskine was committed as a control plot. Microbiological studies were performed using a specific TSM at different concentration levels from 10-4 to 10-5, 10-6, 10-7, and 10-10 in Petri dishes with 6 repetitions each. The mean colonisation rate of Trichoderma spp. was compared between plots. Results showed that the common use of agrochemicals by papaya producers and the fire-prone when implementing papaya fields negatively impacted the development of useful Trichoderma strains in their farms. No Trichoderma strain was found in soil samples for each papaya farm from treated plots (0%). While, all samples analysed from the control plot were 100% productive of the soil-born microorganism sought. Farmers in the Diamare division are encouraged to use eco-friendly cultural methods for preserving Trichoderma spp. in the rhizosphere of papaya trees.