Open Access Short Research Article

Allelopathic Effects of Aqueous Extracts of Ricinus communis L. on the Germination of Six Cultivated Species

Ezzeddine Saadaoui, José J . Martín, Naziha Ghazel, Chokri Ben Romdhane, Nouman Massoudi, Emilio Cervantes

International Journal of Plant & Soil Science, Page 220-227
DOI: 10.9734/IJPSS/2015/16483

Aims: The effect of aqueous extracts of castor bean (Ricinus communis L.) On the germination of six cultivated crops was investigated.
Study Design: Samples of R. communis were harvested from the region of Gabès (south of Tunisia) and tested at laboratory on crops seeds.
Place and Duration of Study: Regional station of Gabès- National Institute of Research in Rural Engineering, Waters and Forests – Tunisia, between October and December 2014.
Methodology: Extracts were obtained after an incubation of 9 g of dry plant material (powder) in 100 ml distilled water during 48 hours at 60°C. The extraction was made from five parts of R. communis (root, twig, leaf, seed and pericarp) and used in germination tests.
Results and Conclusion: Results showed two types of behavior: the aqueous extracts of root, twig, and seed had a low effect of inhibition for all studied species. The aqueous extracts of leaf and pericarp had a high effect of inhibition. C. olitorius is the most tolerant species; its germination rate is 99, 99, 97, 96, 69.5 and 53.5% for aqueous extracts of root, twig, seed, leaf and pericarp respectively. L. culinaris is the most sensitive species; its rate of germination is 97, 68.5, 44, 3 and 0% for aqueous extracts of root, twig, seed, leaf and pericarp respectively. Leaf and pericarp aqueous extracts are the most inhibitive of germination resulting in germination rates lower than 16.5% for all studied species, except for C. olitorius, its germination rate is 69.5 and 53.5% with pericarp and leaf extract respectively. The aqueous extracts of R. communis inhibited root length in all studied species, essentially with the aqueous extracts of leaf and pericarp. These two parts of R. communis showed high allelopathy effect in percentage of germination and root length for all studied species.

Open Access Original Research Article

Association of Different Parametric and Non parametric Stability Models in Durum Wheat (Triticum turgidum Desf.) Genotypes

Fentaw Abate, Firew Mekbib, Yigzaw Dessalegn

International Journal of Plant & Soil Science, Page 192-201
DOI: 10.9734/IJPSS/2015/15568

Thirteen durum wheat genotypes were evaluated in a randomized complete block design with three replications across four locations of north western Ethiopia for two consecutive years (2010 and 2011). The objective of this experiment was to investigate the association of different parametric and non parametric stability models that can be used for stability analysis of multi location trials. Spearman rank correlation showed that a significant positive perfect correlation between Shukla’s stability variance (σi2) and Wricke's ecovalence (Wi) stability models. This indicated that instead of using the two stability models, only one of these stability models can be used for identifying stable genotypes in multi location wheat trials. However, Coefficients of determination (ri2) and deviation from regression (Sdi2) showed a highly significant negative rank correlation (r = - 0.8581), which implies neither of these stability model alone could be sufficient for identification of stable genotypes that had consistence grain yield performance across different locations.


Open Access Original Research Article

Population Structure in Natural Stands, Seed Germination and Seedling Growth of Sterculia setigera under Nursery Conditions in Burkina Faso (West Africa)

Philippe Bayen, Anne Mette Lykke, Amadé Ouédraogo, Adjima Thiombiano

International Journal of Plant & Soil Science, Page 202-210
DOI: 10.9734/IJPSS/2015/17562

The present study aimed at evaluating S. setigera population structure in natural stands and estimating the effect of pretreatment methods on seeds’ germination capacity and seedling establishment. Dendrometrical measurements were performed on 504 S. setigera trees for population structure assessment. The bell shaped structure obtained indicates that the population of S. setigera is unstable and under threat due to lack of recruitments under threat due to lack of recruitments. An experimental design with four randomized blocks corresponding to four replicates of 25 seeds in each pretreatment (sulphuric acid, boiling water, water at room temperature and the control) was used. Seeds were sown in a medium of clay and dung in the ratio 2:1, in polythene plastic pots measuring 7.5 x 25.5 cm. A total of 400 plastic pots were used in this experiment and kept moist. Forty days after sowing, germination rate was assessed. The results showed that sulphuric acid produced the highest (75%) cumulative germination while boiling water had the lowest (8%). Seeds under control pretreatment gave an impressive germination, which did not differ significantly (p= 0.000) from the results of sulphuric acid. The high rate of germination in the control can be taken as an indicator that S. setigera has the ability to produce seedlings but these seedlings face difficulties of establishment in natural areas. Seedlings growth in term of height were significantly (p=0.016) affected by the type of pretreatment used. Acid pretreatment technique showed the highest seedlings performance. Based on the natural population pattern and the germination traits, we could hypothesize that the lack of S. setigera recruitment is primarily caused by water regime in the soil.


Open Access Original Research Article

Influence of Plant Density and NPK 15:15:15 Fertilizer on Some Agronomic Characters and Proximate Composition of Onion (Allium cepa L.) in Edo Rainforest of Nigeria

E. J. Falodun, J. O. Ehigiator

International Journal of Plant & Soil Science, Page 211-219
DOI: 10.9734/IJPSS/2015/16666

The effect of plant population density and varying levels of NPK 15:15:15 fertilizer on the growth, yield and proximate composition of onion (Allium cepa L.) was investigated in a 2-year study, 2010/2011 and 2011/2012. The experiment was a factorial combination of three plant densities 333,333, 250,000 and 160,000 plants ha-1 and four levels of NPK 15:15:15 inorganic fertilizer at 0, 40, 80 and 120 kg /ha NPK laid out as a randomized complete block design with three replications. Results indicated that the three plant densities of 333,333, 250,000 and 160,000 plants ha-1 were statistically similar in both trials and enhanced the growth of onion in terms of stem diameter except at 6 weeks after transplanting (WAT). This trend was also observed for proximate composition of onion leaves and bulbs and number of leaves in 2010/2011. In 2011/2012, the lowest plant density of 160,000 plants/ha produced more leaves compared to the higher plant populations of 333,333 and 250,000 plants/ha. Chlorophyll content, CGR and bulb length were similar at the lower densities and significantly higher than those produced at the highest plant density of 333,333. In both trials bulb yield was significantly similar at densities of 333,333 and 250,000 plants/ha. Increase in fertilizer application significantly increased the moisture content. Crude protein and crude fiber but decreased the percentage dry matter content of leaves and bulbs. However, optimum bulb yield was obtained at density of 250,000 plant/ha with fertilizer application rate of 80 kg/ha NPK 15:15:15.


Open Access Original Research Article

Soil Properties at Different Distances of Intercropping in Three Olive Orchards in Morocco

Karima Bouhafa, Lhoussaine Moughli, Khalid Daoui, Ahmed Douaik, Younes Taarabt

International Journal of Plant & Soil Science, Page 238-245
DOI: 10.9734/IJPSS/2015/16807

Aims: This study aims to investigate the effect of the distance from olive tree on soil fertility in three intercropping (wheat, fababean, and chickpea).
Study Design: Randomized complete block with four replications. The factor studied is the distance from the olive rows.
Place and Duration of Study: The study was conducted during 2014 in farmers’ fields at Dou yet in Morocco. Three olive orchards were chosen with the three intercropping.
Methodology: The planting density of the olive orchards is 10*10 mand planted variety is Moroccan Picholine. After harvesting annual crops, soil samples were taken from 0-30 cm layer at ten different distances from olive rows, with four replications in each of the three intercropping to the olive tree. Soil fertility parameters were determined. Olive leaves were also collected with eight repetitions in each of the three orchards. Leaf nitrogen, phosphorus and potassium contents were determined. The olives yield components were determined on a sample of 30 fruits per tree, taken at harvest, with eight repetitions in each of the three olive orchards.
Results: The olive yields in this year were 1.7, 2.5 and 3 t.ha-1 for trees associated with wheat, fababean and chickpea, respectively. The distance from the olive row had different effects on the soil parameters within each intercropping in the olive orchards. For wheat, the maximum organic matter content was recorded near the tree (distance 0). For fababean, the distance from the olive row had no effect on all soil parameters. In chickpea plot, the distance from the olive row affected only the soil nitrate content with the maximum level was recorded at 5 meters from the olive row.
Conclusion: This study shows that fertilization of the combination of olive tree and intercrop should take in to the count, the associated species and the distance from olive tree for an efficient use of mineral fertilization.

Open Access Original Research Article

Growth, Nutrient Uptake and Dry Matter Yields of Maize (Zea mays L. var) Grown with Different Levels of Organic and Inorganic Fertilizers in Morogoro, Tanzania

U. K. Adamu, J. P. Mrema, J. J. Msaky

International Journal of Plant & Soil Science, Page 246-255
DOI: 10.9734/IJPSS/2015/17978

A screen house study was conducted at the Department of Soil Science Screen house SUA, Morogoro to determine the effects of different levels of N, P and FYM on the growth, nutrient uptake and dry matter yield of maize. The experimental design used in the study was factorial design in RCBD (Randomized Complete Block Design) The results obtained indicated that application of different rates of N, P and FYM had significant influenced on the growth, nutrients uptake and dry matter yield of maize. Plot with Farm yard manure (FYM) was combined N and P fertilizers. Results on plant height ranged from 8.50 to 40.25 cm in control and from 9.38 to 67.00 cm in plants treated with 150 40 kg NP ha-1 with FYM 10 ton ha-1 of FYM. Plant growth, nutrient uptake and DMY were significantly (P < 0.05) influenced by treatments. Plot treated with 150 kg N ha-1, 80 kg P ha-1 and 5 t FYM ha-1 significantly had higher N (2.94%) content, while plot treated with 75 kg N ha-1, 80 kg P ha-1 and 5 t FYM ha-1 had higher P (0.39%) content. It is therefore concluded that, different levels of FYM with N and P were equally effective in enhancing nitrogen and phosphorus uptake by maize.


Open Access Review Article

Roles of the Plant Immune Response in Root Nodule Symbiosis

Maggie McCormack, Karolina Pajerowska-Mukhtar

International Journal of Plant & Soil Science, Page 228-237
DOI: 10.9734/IJPSS/2015/17661

The symbiotic relationship between legume plants and soil bacteria has been an important focus of research for several decades because of its agricultural and environmental potential to create a variety of nitrogen-fixating plants capable of fertilizing the soil and producing crops with high protein content. The symbiosis is largely plant-controlled, with the plant’s innate immune responses playing an important role in initiating and regulating the symbiosis. This review elucidates the role of plant immune responses in forming symbiosis with microorganisms, including how molecular cues between host and symbiont suppress the plant defense pathways, as well as how the plant can dominate the symbiosis through defense-like reactions at key signaling steps in the symbiosis. Understanding the mechanisms of regulated defense responses during nitrogen-fixing symbiosis may help us transfer this ability into non-legume plants, creating crops with higher nutrient yields and promoting sustainable and environmentally-friendly agricultural practices.