Open Access Original Research Article

Influence of Soil Fertility on Herbaceous Community Structure in Dunes and Swamps of the Coastal Plain of Laguna, South Brazil: An Ecological Approach

J. C. F. Melo-Júnior, S. S. Dornelles, A. D. Viana, A. A. Ribeiro, A. M. Ruthes, A. Aviz, B. C. Fernandes, B. C. Reginato, C. I. Telles, D. G. Mayer, G. Teixeira, G. H. D' Ambrósio, G. Lamin, G. M. Castilho, G. C. Mussoi, H. S. Devigili, J. B. Lopes, J. A. Falletti-Netto, J. M. Conrado, L. S. Bianchini, M. F. Goulart, M. C. Brand, T. S. Steffens, V. F. Silveira

International Journal of Plant & Soil Science, Page 1-11
DOI: 10.9734/IJPSS/2017/37998

This study aims to evaluate the influence of soil nutrition on the organization of restinga communities on two different geoformations in the post-beach region. Studies were carried out at Laboratory of Morphology and Plant Ecology and Marine Biological Science Course, Joinville Regional University, in coastal plain of the municipality of Laguna, Santa Catarina, Brazil, during August 2017. A phytosociological survey was performed using 1 x 1m plots distributed along four parallel transects spaced about 200m apart (50 plots were located on parabolic dunes and 50 plots were located on swamp of intercordion depressions). Chemical characterization of the soil of the parabolic dunes and the intercordion depressions adopted conventional soil protocols. The phytosociological survey recorded 28 species distributed among 25 genera and 12 families of angiosperms. Of these species, seven were found co-occurring in parabolic dunes and swamps of intercordion depressions, whereas the others were unique to one or the other geoformation. Swamp showed bigger diversity than dunes. The most diverse families were Asteraceae (9), Cyperaceae (5) and Poaceae (5), which accounted for 79.2% of the total number of species surveyed. The dune soil had higher salinity, while the swamps had greater availability of water and fertility. The results obtained in the present study corroborate the indissociable plant-soil relationship attributed to restinga environments, specifically that increases in both species richness and abundance are associated with higher fertility and water availability of soil, and whose edaphic climax is notorious in the most settled communities near the sea.

Open Access Original Research Article

Soil Characterization and Classification of the Koutango Watershed in the Semi-Arid Southern Peanut Basin of Senegal

M. Diack, F. Diom, K. Sow, M. Sène

International Journal of Plant & Soil Science, Page 1-13
DOI: 10.9734/IJPSS/2017/37803

The study was conducted to determine the potential of soil units composing the watershed for agriculture. The methodological approach was based on a soil profile description and sampling of soil units in different depths. The soil physical and chemical properties such as soil texture, soil pH, electric conductivity (EC), soil organic carbon (SOC), total nitrogen (N), extractible phosphorus (P), cation exchange capacity (CEC), were measured using standard methods. Results showed differences for SOC at the surface (2.9-5.85 g kg-1), N at the surface (0.3-0.45 g kg-1) and (P) at the surface as well (12-58 g kg-1). Soil characteristics have allowed to come up with a soil classification. Results also showed that the lowland soil unit presented higher soil properties contents, followed by colluvium and terrace soil units, the upland unit had the lowest soil contents. With reference to soil nutrient ratings, except for extractible phosphorus, value contents of chemical properties were below critical values, leading to the lowest soil fertility level and therefore emphasizing the need to include agricultural management practices that can influence soil variability.

Open Access Original Research Article

Effect of Time of Exposure on the Antimicrobial Potentials of Some Tropical Plants against Cocoa Pod Rot Pathogen- Phytophthora megakarya (B & G) in Nigeria

E. A. Babalola, B. A. Ogundeji, S. O. Adio, A. O. Adeji

International Journal of Plant & Soil Science, Page 1-8
DOI: 10.9734/IJPSS/2017/37039

Aims: To determine the effect of time of exposure on the antimicrobial effectiveness of some tropical plants in the control of black pod disease of cocoa caused by Phytophthora megakarya in Nigeria.

Study Design: Completely Randomized Design (CRD).

Place and Duration of Study: Plant Pathology Section, Cocoa Research Institute of Nigeria (CRIN), Ibadan, Nigeria, from 2015 to 2016.

Methodology: The antimicrobial effects of aqueous extracts of six selected Tropical plants: Moringa oleifera, Sida acuta, Piper guineense, Ocimum gratissimum, Chromolaena odorata and Cymbopogon citratus against Phytophthora megakarya, causal agent of black pod disease of cocoa was investigated in an in vitro experiment. 200 g leaf samples of each of the plants used were surface sterilized, mashed separately and the resultant pastes were soaked in 200 ml of sterile distilled water and filtered. Varied concentrations of the extracts (10, 25, 50 and 75%) were pour-plated with freshly prepared potato dextrose agar (PDA). Disc culture (5 mm) of Phytophthora megakarya was inoculated into each of the PDA plates and incubated at 25°C for 144 hours.

Results: Aqueous extracts of the six plants, at varied concentrations showed different levels of inhibition against the pathogen. C. odorata at all tested concentrations consistently reduced the mycelia growth and showed significantly highest percentage inhibition (P .05) against the pathogen, followed by Sida acuta, P. guineense, O. gratissimum and C. citratus while M. oleifera gave significantly lowest inhibitory percentage (P < .05).

Conclusion: Findings from this research showed that the antimicrobial effectiveness of all the botanicals used decreased with time contrary to that of the standard (chemical fungicide) used. Aqueous extracts of C. odorata having shown some promise, could therefore be used as bio-fungicide in the control of black pod disease of cocoa, but with intermittent application.

Open Access Original Research Article

Effect of Deficit Irrigation Levels on Yield and Water Productivity of Some Maize Varieties in a Semi-arid Environment

A. M. Yamusa, E. C. Okogbue, S. O. Agele1

International Journal of Plant & Soil Science, Page 1-9
DOI: 10.9734/IJPSS/2017/32847

The aim of this research is to determine the appropriate irrigation scheduling under three different maize varieties in Northern Guinea Savanna agro ecological zone of Nigeria. The trial was conducted during the 2015 and 2016 dry seasons at the Institute for Agricultural Research (IAR) field in Samaru (Latitude 11.11° N and Longitude 7.38°E). The experiment was laid out as a split – plot design replicated three times. Planting dates and supplementary Irrigation levels were in the main plots while maize varieties formed the sub-plots with the planting dates at 10days interval starting from March and February respectively. Three levels of irrigation were imposed based on levels of cumulative pan evaporation (Epan ) values of 1.0 Epan  (EI1), 0.70 Epan  (EI2) and 0.40 Epan  (EI3). Results from the two trials, revealed more efficient utilization of soil moisture by crops irrigated with 70 CU irrigation regime (6.91 and 6.97 kg grain/mm water respectively for the two seasons) while the least efficient water use was recorded by the full CU treatment (6.63 and 6.93 kg grain/mm water respectively) with relatively higher grain yields of 14% and 20% more than the 70 CU and 40 CU regimes respectively in 2015. Similar trends were recorded in the case of cob weight, 100 seed weight, seed/cob, shelling percentage and harvest index. In 2016 season, the similar trend was observed indicating the highest grain weight (3348.0 kg/ha) recorded by the full irrigation treatment which was statistically higher than (2724.0 and 2072.0 kg/ha) respectively for the 0.70 and 0.40 CU regimes. The best performing variety in terms of efficient water use and relatively high yield was the medium maturing variety (V3).

Open Access Original Research Article

Potassium Critical Limit and Response to Soybean in Swell-Shrink Soil, Akola, Maharashtra

Jaya Tamgadge, S. N. Ingle, Sandeep Kumar Tripathi

International Journal of Plant & Soil Science, Page 1-8
DOI: 10.9734/IJPSS/2017/37938

The emerging role of K in a number of biotic and abiotic stress situations is discussed including those of diseases and pests, frost, heat/drought, and salinity. A net house investigation was undertaken with 15 soils belonging to swell-shrink soils of Central Research Farm of Akola to determine the critical limit of K and response of soybean (Glycine max L. culture plant JS-335) to K application. The plants were grown up to 45 days and per cent Bray’s value was calculated for each soil which varied from 69.56 to 96.15. The critical limit of K in swell-shrink soil extracted by neutral normal ammonium acetate in statistical method is 143 kg ha-1 and 148 kg ha-1 for soil in graphical method. The critical limit of K for soybean plant at 45 days growth was 0.43 per cent by statistical method and 0.47 per cent by graphical method.