Application of Composited Municipal Refuse Dump Site Soil, Orange, Potato and Pineapple Peels in the Control of Root Knot Nematode (Meloidogyne Incognita) Infecting Carrots (Daucus Carota L.)

Abstract

Meloidogyne incognita is known to be a foremost pest of carrot in Nigeria. It is a component to appraise in carrot production. Application of synthetic nematicides as control measures is unsafe to humans and detrimental to the environment. Development of safe control process is worthwhile. Effect of three peels (potato, pineapple, orange) and composited soil from municipal refuse dump site was assessed and compared with carbofuran a standard synthetic nematicide at four different doses (0, 1500, 2000, 2500g and 2.0kg/a. i/ha, 1.5kg/a. i/ha, 1.0kg/a. i/ha and 0kg/a. i/ha for carbofuran) on carrot plants. The concentrations of heavy metals like Cd, Pb, Ni, Cu, Cr, Mn, Zn and Fe in the composited soil was determined with Atomic Absorption Spectrophotometer (AAS). Experimental pots were inoculated with approximately 2000 M. incognita juveniles, in a randomized complete block design experiment. The composited municipal refuse soil was analysed for the presence of fungi and bacteria using molecular methods based on 16S rRNA gene sequencing. Reproduction and multiplication of M. incognita was significantly (p<0.05) low with all the treatment materials. Best inhibitory effect was observed in the soil of carrot plants treated with composited soil which had 49 nematode populations at harvest rather than 4606 recorded in untreated plants. Equally, heavier carrots were harvested in plants administered with composited soil (1309.6 gram), while the control plants had poor weight (312.7 gram). Performance of each waste material was quantity dependent. Gene sequencing revealed the presence of Pseudomonas alcaligenes strain ATCC 14909, P. putida strain ATCC 12633, P. aeruginosa strain ATCC 10145, Pseudomonas stutzeri NBRC 14165, Acinetobacter venetianus ATCC 31012, Enterobacter cloacae ATCC 130047, Streptomyces spp B7-3TC02, Bacillus subtilis NBRC 13719, Aspergillus niger strain MPVCT 158, Penicillium georgiense strain EV 24 and Rhizopus oryzae strain ATCC 20344, which are beneficial soil microorganisms. The metal concentration analysis of the composited municipal refuse dump soil exhibited low concentrations of heavy metals which ranges from 0.002-1.03 mg/kg with Zinc (Zn) having the highest concentration. The waste materials are cheap and ecofriendly option that can be adopted as soil amendment in M. incognita infested fields to significantly boost yield in carrot production and reduce reliance on mineral fertilizer. The peels, as well as composited municipal refuse dump soil can be used to improve soil properties and substitute lost nutrients to enhance crop production, and at the same time mitigate the environmental consequences of inappropriate waste disposal problems in Nigeria.