Each treatment was replicated three times; with a treatment of Furadan (commonly used in commercial plantain production), with the addition of wood ash, and with nothing added. The organic manures also maintained pH, regulated soil temperatures and conserved soil moisture while commercial inputs significantly increased acidity.
In the traditional compound system of growing plantains, household livestock and kitchen waste and woodash are continually applied. These systms sufferer less damage from plantain weevils(Cosmopolites sordidus) and nematodes (Helocotylenchus multicintus) and Meloidogyne incognita) than do non compound systems . Commercial systems rely on chemical nematacides. The traditional applications of organic matter are not feasible for production on a scale larger that of the rural compunds, therefor a balanced compost is needed.
The experiment was conducted at Owerri, in a tropical rainforest on a sandy loam Ultisoil. Nine treatments were applied using composted household refuse, refuse and poultry manure, and refuse and cattle manure. Each of these was treated with either Furadan 5G(24 kg/ha), wood ash (48 kg/ha) or was untreated. These were applied at 16 t/ha. NPK was applied to the control plots (320 kg/ha of both 21%N and 46%K2O, 160 kg/ha of 18% P2O5). Each treatment was 25 sword suckers of false horn plantain spaced 2.5x2.5 m apart.
The compost was applied prior to planting at 10 t/ha, harrowed into the soil and 4 months later applied in a ring around each plantain. Manure applications continued for the first ratoons. The plots were hand weeded. Data was taken after the second ratoon harvest. Samples taken from within 15 cm depth of the mats in each plot, from the soil, plantain rhizomes, and the root samples. Nematode and Plantain Weevil populations were counted.
The results showed that plantains mulched with the compost combination of poultry FYM, refuse, and wood ash had the highest yields and rate of establishement, were harvested earliest and had the lowest rate of pest infection. With the poultry FYM and ash compost the plantains yielded 10.9 kg/plant. Cattle FYM and ash yielded 9.8 kg/plant. The NPK control with Furadan yielded 10.6 kg/plant. Refuse alone yielded the lowest with only 7.2 kg/plant.
Weevil infestation was highest with refuse alone at 17.6%, and lowest with poultry FYM + ash at 2.2%, while poultry manure alone had 4.8% infestation. The addition of either ash or Furadan to the compost rduced weevil infestation from that of the composts alone. Cattle FYM alone had 8.5% infestation, cattle FYM + ash: 4.6%, and cattle FYM and Furadan: 4.8%. The wood ash also served as a source of mineral nutrients for the plantains.
Although the exact reason for the reduction of the insect and nematode population by the ash is not known, it is accepted that the pressence of the ash slurry inpedes nematode egg hatching and larvae.