Effect of pit-composting on root-knot nematode (Meloidogyne incognita and M. javanica) population densities and yield of tomato under field conditions

Soil amendments, constituting of various plant and animal sources, were evaluated in pits for their effects on Meloidogyne spp. infecting tomato in comparison to the synthetic nematicide fenamiphos and the untreated control. Fifty-six days after transplanting, soil and root samples were collected for nematode extraction and counting while fruit mass and the number of fruits were also recorded and the average yield per treatment calculated. The plant-based pit-composting treatments decreased nematode population densities, from 43% to 94%; with the citrus fruit-pit compost being the most effective (reducing nematode densities by up to 94%). Conversely, chicken and cattle manure treatments generally resulted in increased nematode densities (up to 141% and 159%, respectively). Increases in tomato yield ranged from 7% to 94% in response to compost, cattle and chicken manure treatments while all pit-composting significantly enhanced yield ranging from 100% to 400%; except for the shrub-pruning pit compost which decreased yield. Pit-composting is a promising strategy that can be used by especially subsistence farmers to grow crops sustainably in the presence of lower nematode pest densities.