Efficacy Of Soil Solarization Research Articles

Efficacy of soil solarization on the control of root-knot nematodes infecting eggplant (Solanum melongena) in Plateau State

The efficacy of soil solarization was tested for the control of root-knot nematodes in Foron District of Barkin Ladi Local Government Area of Plateau State using three commercially available cultivars of eggplant (Solanum melongena) namely: Yallo Bello, Chida Masoyi and Farin Yallo. Two levels of soil solarization based on time of exposure namely: Four weeks, five weeks and a control were employed. Soil temperature for each bed was taken weekly in the morning and afternoon using soil thermometer at different soil depths. Results revealed that growth and yield parameters of eggplant namely plant height, stem girth, number of leaves, number of fruits, and fresh weight of fruits grown in solarized soil were significantly higher than those of the control (unsolarized soil) at 0.05 level of probability. More galls were seen on the roots of unsolarized plants, followed by the four weeks and the five weeks’ solarization had the least. This is indicative of the effectiveness of soil solarization in the control of nematodes, especially for longer periods of solarization. The three cultivars of eggplant did not differ with reference to soil solarization. Soil solarization could be an effective tool for nematode control on the Plateau since it is cheaper, has no phytotoxic effects, and does not constitute environmental and health hazards. The technique can be improved with more investigation’s on length of exposure and improvement of the durability of the polyethylene film. Continuous use of these polyethylene films will reduce the cost of buying the polyethylene films repeatedly when it is needed. Key words: Soil, Solarization, Solanum melongena, nematodes, efficacy.

Efficacy of soil solarization on black root rot disease and speculation on its leverage on nematodes and weeds of strawberry in Egypt

BackgroundStrawberry (Fragaria ananassa Duch.) is an economically important crop in Egypt. Yet complex black root rot disease of strawberry caused by Fusarium solani, Rhizoctonia solani, and Pythium sp. can cause considerable yield losses. Therefore, this study aimed at evaluating different aspects of soil solarization against this disease. Such an evaluation would better be viewed in the context of other beneficial effects of soil solarization on nematodes and weeds.Materials/methodsGrowth agar disks, growth suspension, and resting stages of strawberry black root rot fungi were evaluated at different temperatures and exposure times using digital hot water bath. Cloth bags artificially infested with single fungal species were buried into the soil before soil solarization at soil depths of 1–10, 11–20, and 21–30 cm at three spots of each plot for each of the abovementioned fungi for 3, 6, or 9 weeks. The disease incidence and severity in solarized and un-solarized soil was compared with the application of the fungicide Actamyl. Effects of soil solarization on nematodes and weeds were also consulted.ResultsThe lethal temperature to F. solani, Pythium sp., and R. solani was 58, 58, and 56 °C, respectively when exposure time was 1 min. Chlamydospores were killed at 62 °C while sclerotia were killed at 58 °C in hot water for 1 min. Maximum soil temperature in solarized soil was raised by 15, 14, and 12 °C at depths of 1–10, 11–20, and 21–30 cm as compared with non-solarized soil. Solarization for 3, 6, and 9 weeks significantly reduced the disease incidence and severity and increased the strawberry yield. Complete reduction in total count of all tested fungi was obtained after 9 weeks at all tested depths. A review of collective soil pest and pathogen control via solarization documented its beneficial application.ConclusionThe study may exploit hot months in Egypt for soil solarization against the serious root rot disease either singly or in an integrated pest management program.

Soil solarization based on natural soil moisture: a practical approach for reducing the seed bank of invasive plants in wetlands

Soil solarization is a well-established method to disinfect soil for efficient weed control. However, the feasibility of applying this method in the restoration of invaded natural habitats is unclear. This is because soil moisture is necessary for the success of solarization, but pre-irrigation in natural ecosystems is often not applicable, or demands high labor investment, making it unsuitable for use in restoration. The present study was based on the idea that the relatively high soil moisture in wetlands might obviate the need for pre-irrigation, rendering this method much more applicable in natural habitats. We examined the efficacy of soil solarization using natural soil moisture to control the seed bank of the invasive plant, Acacia saligna, in a wetland, using large-scale experimental plots (0.38 ha each). An old, dense A. saligna grove was cut down and the roots were removed by a bulldozer. The plot was mulched with a transparent polyethylene sheet in early July and left on the soil for 14 weeks. Soil solarization significantly reduced the viability of seeds of A. saligna that had been experimentally buried. Additionally, viability of seeds in the natural seed bank was reduced, and seedling emergence was close to zero. Exposing seeds to soil temperature and soil moisture levels equivalent to those obtained during field soil solarization under controlled conditions significantly increased the release from dormancy of the seeds, suggesting that release from dormancy during the early stage of solarization is a critical stage leading to seed weakening or mortality in the soil. Soil solarization also decreased the cover and abundance of the natural vegetation; therefore, active revegetation is required to restore the natural vegetation and to conserve endangered and endemic species.

Efficacy of soil solarization, Trichoderma harzianum, and coffee pulp amendment against Armillaria sp.

Soil solarization was evaluated singly or in combination with Trichoderma harzianum infestation or coffee pulp amendment for its effect on wood-borne inoculum of an Armillaria sp. pathogenic on tea. Solarization increased maximum soil temperatures at 10cm depth by 9–12°C and reduced viability of Armillaria sp. up to 100%. Its efficacy was similar at 5, 10, and 15cm soil depths. Trichoderma harzianum applied to the soil surrounding the blocks of inoculum also significantly reduced viability of the pathogen. Application of 20g of the wheat bran culture of the antagonist in every 1000cm3 of soil surrounding the blocks of inoculum, following solarization for 5 week, caused total loss of Armillaria inoculum viability and was similar to 10 week of solarization without application of the antagonist. The coffee pulp amendment reduced inoculum viability slightly though this effect was apparent only in non-solarized soil.

Improved method of bench solarization for the control of soilborne diseases in basil

Soil solarization, carried out in raised concrete benches in two subsequent years, proved very effective against Fusarium oxysporum f. sp. basilici and Rhizoctonia solani on basil. The temperatures reached in mulched benches at 5 and 15 cm depth were respectively 48 and 45 °C. The efficacy of soil solarization against Fusarium wilt was generally not improved by combining with strains of Fusarium spp. antagonistic to F. o. f. sp. basilici.

Evaluation of soil solar heating for control of damping-off fungi in two forest nurseries in France

Field experiments were carried out at two different forest nurseries during the summer of 1994 to examine the efficacy of soil solarization for the control of damping-off. Both soils hosted Pythium spp., Fusarium spp. and Rhizoctonia solani as damping-off agents. Soil samples from solarized, steamed, fumigated and untreated plots were periodically collected and assayed for soil infectivity. Solarization with a double layer of polyethylene film was as effective as steaming or fumigation in reducing soil infectivity in the uppermost layer. During July the temperature of covered beds rose as high as 50°C at a soil depth of 5cm. The method achieved good control of Pythium spp., the main cause of damping-off at both nurseries, whereas Fusarium spp. were more tolerant. The association of Trichoderma spp. with a reduction of soil infectivity at the last sampling date strongly suggested that biocontrol processes were induced after solarization. Soil solarization provides a suitable method for control of damping-off.

Influence of soil solarization on the viability ofFusarium solaniin an arid environment

Abstract Efficacy of soil solarization (polyethylene mulching) was tested against a root rot fungus, Fusarium solani, in hot arid environment. Mulching during the month of June increased soil temperatures by as much as 12 and 9°C at 5 cm depth in dry and wet plots, respectively, resulting in a pronounced reduction of F. solani population. An initial population of 250 propagules g‐1 soil was reduced to 13 (dry) and 7 (wet) propagules during a period of 15 days. Elimination of propagules at 15 and 30 cm soil depth was relatively low. Considerable reduction in the Fusarium population occurred in moistened nonmulched soil, indicating a possibility of disease control by the application of a single irrigation in summer months.