This study identified areas where different types of herbicide were used for municipal weed control in selected residential communities in Akure, Akungba-Akoko and Owo in Ondo State, Nigeria. A survey of the communities was carried out to identify sites maintained with herbicides (test sites) and those without herbicide history (control sites). Composite soil samples collected from each site were analyzed using standard laboratory procedures for the determination of selected soil physical and chemical properties. The data obtained were subjected to statistical analysis of variance (ANOVA). Results obtained indicated that the soil texture of the study sites were mostly sandy loam while pH ranged from slightly acidic to neutral. Significant differences (P < 0.05) were observed in the organic carbon (OC) contents of soil samples from Owo as against the samples from Akure and Akungba-Akoko though Owo had the highest OC (24.48 ± 9.36 g kg-1) followed by Akungba-Akoko (21.21 ± 10.36 g kg-1) and Akure (18.10 ± 7.75 kg-1) which was the lowest. However, no significant differences (P < 0.05) were observed in the values of the micronutrients and exchangeable cations across all the sites. Conclusively, application of herbicides to weeds did not have significant effect on the soil fertility (in all the sites) in the short run (2013-2015) but more aggressive application could have deleterious effects in the long run because leaching is encouraged as a result of the sandy nature and low organic carbon content of the soil in the study areas.

Commelina maritima L. is a dominant perennial halophyte that is restricted to sandy beaches where it plays major ecological roles in Southern Nigeria. This study examines the response of this plant to saltwater sprays, a factor that affects the growth of coastal plants. Plants were sprayed with seawater twice per week (2/week), four times per week (4/week) or six times per week (6/week) while control was sprayed without seawater (de-mineralized water) six times per week (0/wk). Survival, growth and biomass allocation of the plants were determined. Salt spray did not affect plant survival but significantly (p≤0.05) decreased number of leaves, shoot length, stem girth, leaf area and root growth. Relative growth rate and number of branches were not significantly (p≥0.05) affected by salt spray. Sea spray significantly (p≤0.05) reduced fresh and dry mass of plant parts, total biomass and leaf total chlorophyll when compared with the control. Root : shoot ratio increased significantly (p≤0.05) under seawater treatment as the shoot growth was more negatively affected than root growth. Relatively more biomass was allocated to the root than shoot in seawater-treated plants. Salt spray increased shoot ash content and negatively affected plant organic content. C. maritima can be classified as a salt spraysensitive plant. Salt spray is a micro-environmental factor affecting its survival and growth, thus influencing its distribution in strandline.

This study investigated the distributional patterns of species in response to salinity gradients. The vegetation was systematically sampled using a quadrat of 50 x 10 m. Vegetation variables were measured. At depths of 0-15 and 15-30 cm, sediment samples were dug and analyzed using standard methods. Fourteen species were encountered. Rhizophora mangle and Mytragyna ciliata had highest and least density values of 6664±687.16 and 3.00±0.42 st/ha. The most frequent species were Rhizophora mangle and Nypa fruticans (100 %). Rhizophora mangle and Mytragyna were tallest (12.45±1.20 m) and shortest species (3.11±0.24 m). Elaeis guineensis and Alchornea cordifolia had the largest (1.79±0.05 m 2 /ha) and least (0.008±0.0002 m 2 /ha) basal area values. Highest crown cover value was recorded by Rhizophora mangle (9.14±0.08 m2/ha) while by Alchornea cordifolia had the least value (0.04±0.001 m 2 /ha). Gradient analysis revealed that Ipomoea involucrata, Paspalum vaginatum, Dracaena mannii, Piptadeniastrum africanum, Elaeis guineensis, Staudtia stipitata, Alchornea cordifolia, Terminalia superba and Mytragyna ciliata belonged to ecological group 1 with ecological optima of 8.14, respectively. Acrostichum aureum (ecological optimum of 29.32), Avicennia africana (ecological optima of 19.56 and 30.12) and Phoenix reclinata (ecological optima of 8.14 and 29.32) belonged to ecological group 4 while Nypa fruticans (ecological optima of 8.14 and 29.32) and Rhizophora mangle (ecological optima of 19.56 and 30.12) belonged to ecological group 0. This study provides information on species adaptation and performance in relation to environmental stress and will form the basis for the future and effective management of this ecosystems.

Soil salinity is a severe environmental stress that limits crop growth and productivity. Mycorrhizal fungi association has the potential to minimize environmental stress like soil salinization in some plant species. Hence, an experiment was conducted to examine the potential of an Arbuscular mycorrhiza (AM), Glomus clarum, to reduce salt stress in Abelmoschus esculentus L. (okra). Seedlings of A. esculentus were raised in perforatedplastic pots filled with 3 kg top soil; treated with 0 (control), 35, 70, 140, 280 or 560 mM NaCl solution; and grouped into two. Each pot in the first group was inoculated with 20 g of AM spawn while pots in the second group were not inoculated with the mycorrhizal fungus. The experiment was laid out in a completely randomized design with each treatment replicated 5 times. Growth parameters in plants without AM including plant height, stem girth, leaf area and number of leaves decreased significantly with increasing salt concentration compared to the control. Salinity also reduced the growth parameters in plants with AM but did not differ significantly from the control. Fresh and dry weight of plant parts, total biomass, number of fruits, fruit fresh and dry weights as well as leaf total chlorophyll were reduced by salinity, but significant differences were recorded only in plants without inoculation with AM. Salinity with or without AM did not significantly affect fruit nutritional and proximate composition of A. esculentusnexcept Na+ that increased with increasing soil salinity. Inoculation of saline sites with arbuscular mycorrhizal fungus, Glomus clarum, could serve as a sustainable and environmentally safe treatment to enhance salinity tolerance in okra for improved productivity. Keywords: Salt stress, arbuscular mycorrhiza, okra, productivity