Open Access Original Research Article

Foliar Heavy Metal Concentrations of 19 Tree Species Grown on a Phytocapped Landfill Site

Kartik Venkatraman, Nanjappa Ashwath

International Journal of Plant & Soil Science, Page 100-113
DOI: 10.9734/IJPSS/2015/13099

An alternative landfill capping technique ‘Phytocapping’ (establishing plants on the waste directly, or on a layer of soil placed over the waste) was trailed at Rockhampton, Australia, as it is eco-friendly, less expensive and socially acceptable. In this capping trees are used as ‘Bio-pumps and Screen’ and soil cover as a ‘Storage’. They together minimise water percolation into buried waste leading to reduced leachate production. Twenty one tree species were grown on two soil depths and monitored for their growth and their ability to restrict water infiltration through the buried waste. A very common question raised by most scientist and engineers is the heavy metal uptake by the tree species and its impact on flora and fauna. Hence to determine the heavy metal concentration in trees species and its cycle within the phytocapping system, foliar and foliar litter heavy metal concentrations were measured in all the tree species grown on the phytocapped landfill site. Results from this analysis suggest that heavy metal composition of the leaves show no real elevated concentrations except in Glochidion lobocarpum which showed high levels of cobalt and Acacia harpophylla and Hibiscus tiliaceus which showed higher levels of arsenic cadmium respectively.

Open Access Original Research Article

Status of Selected Properties of Soils under Crop-Livestock Farming System in Eastern Ethiopia

Lemma Wogi, J. J. Msaky, F. B. R. Rwehumbiza, Kibebew Kibret

International Journal of Plant & Soil Science, Page 114-123
DOI: 10.9734/IJPSS/2015/13425

Information on soil properties and fertility status of soils at farm levels under particular farming system is essential for boosting farm productivity and for sufficient food production. This study was conducted to investigate status and properties of soils under crop-livestock farming system, where crop grains are produced for food security and residues for animal feed and domestic fuel consumption. For the study, two farms under similar farming system were selected from two districts in eastern part of Ethiopia: Adele farm from Haramaya and Bala Langey farm from Kersa districts. Soil samples were collected from crop fields of each farm and analyzed following standard methods for soil physical and chemical analyses. The results indicate that soil textural class is sandy clay loam at both farms. The mean bulk density values were 1.43 and 1.39g cm-3 for Adele and Bala Langey farms, respectively. The soil reaction for Adele farm was neutral (pH=7.23) whereas soils of Bala Langey farm had slightly acidic reaction (pH=6.57). Organic carbon contents of soils of both farms were low, less than 1.5%. Nitrogen was low for Adele farm soils (<0.15%) and in the moderate range for Bala Langey farm soils (0.15-0.25%). Available soil P was very low at both farms (<10mgkg-1). Extractable soil sulfur was also low for both farms (<5 mgkg1). CEC of the soils of Adele farm was very high (>50Cmol (+)kg-1 ) and it was high (>40 Cmol(+)kg-1) for Bala Langey farm soils. Exchangeable base contents and EDTA extractable micronutrients were in the sufficiency ranges for soils of both farms. This study indicated that very low available phosphorus, low organic carbon and nitrogen followed by sulfur are the most productivity limiting factors associated with soil fertility as a result of crop residues removal for animal feed and domestic fuel consumption. Intervention management should focus on the enhancement of organic carbon, phosphorus, nitrogen and sulfur.

Open Access Original Research Article

Laboratory Assessment of the Levels of Resistance in Some Bean Varieties Infested with Bean Weevils (Acanthoscelides obtectus and Zabrotes subfasciatus)

Chancy B. Sibakwe, Trust Donga

International Journal of Plant & Soil Science, Page 124-131
DOI: 10.9734/IJPSS/2015/6809

The main objective of the study was to assess levels of resistance of some selected bean (Phaseolus vulgarisL.) varieties to storage bruchids (Common bean weevil Acanthoscelides obtectus (Say) and Mexican weevil Zabrotes subfasciatus). Specifically it aimed at determining bruchids emergence and median development period, finding out the extent of damage caused by the bruchids on each variety and determining the weight loss incurred by each variety due to bruchids infestation. The experiment was laid out in a Complete Randomized Design (CRD) with four replicates. The study was conducted at Bunda college of Agriculture-Department of Crop and Soil Sciences-Entomology Laboratory. It was conducted from September 2012 to January 2013. Seven bean varieties, Kalima, Nasaka, BCB3, Sapelekedwa, BCB1, Bwenzilaana, and BCB2 were used as test materials. 100 g of bean seeds sample from each variety were put in kilner jars and were infested with 16 bruchids of common weevil and Mexican weevil, and it was carried in two phase; the first phase was used collect data for emerging insects and median development period; and Second phase was used to collect other data parameters. The results at P=.05 only BCB2 was found to be significantly resistant to storage bruchids, Sapelekedwa was the only moderate resistant, Nasaka, BCB3 and Kalima were susceptible and finally Bwenzilaana and BCB1 were highly susceptible. The results also showed that the damage caused by the storage bruchids ranged from 20% in resistant varieties to 88% in high susceptible varieties while the weight loss ranged from 3% to 29%. It was concluded that the level of resistance among the seven varieties evaluated to two common bean weevils (Acanthoscelides obtectus and Zabrotes subfasciatus) differed significantly during the four and half month’s storage period.

Open Access Original Research Article

Identification of Causative Pathogen of Flower Bud Wilt Disease in Dendrobium sp. and In-vitro Growth Inhibition by Medicinal Plant Extracts

M. L. M. C. Dissanayake

International Journal of Plant & Soil Science, Page 132-139
DOI: 10.9734/IJPSS/2015/12370

Aims: The aim of this study was to isolate and identify the causal agent of wilting of flower buds of Dendrobium orchid in Sri Lanka and to search for environmental friendly control measures for flower bud wilt disease as a possible alternative to synthetic fungicides.
Study Design: The experiment was conducted using a completely randomized design.
Place and Duration of Study: Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka from June 2013 to May 2014.
Methodology: The causal fungus isolated from the diseases plant was identified based on their morphology, pathogenicity and ribosomal DNA spacer sequences. The media amended with methanol plant extracts of different concentrations (25%, 12.5%, 6.25%, 3.125%) of tested medicinal plants were inoculated with mycelia discs (4 mm diameter) taken from the advancing edges of 10 day-old pure cultures ofisolated fungus andincubated for 7 days. The fungicidal activities of MIC of methanol extracts were studied after immersing fungal blocks in solution for 1, 3, 6, 12 and 24 hours respectively. The media amended with methanol and recommended fungicide were considered as negative and positive control respectively.
Results: Based on morphological characteristics and rDNA spacer sequences, isolates were identified as F. proliferatum. This is the first record of flower bud wilt disease in Dendrobium sp. in Sri Lanka. Results showed that radial growth of fungus was significantly impaired (P<0.05.) by the addition of the extracts in the culture medium used. The test fungus differed in their reaction to the different extracts but on the whole, growth inhibition increased with the concentration of each extract. The most active extracts, 25% methanol extracts from sweet flag shows a marked effect with inhibition values of 77% against F. proliferatum whereas those from wild basil inhibited the growth by 55%. Out of four plants extract screened, sweet flag showed more than 80% fungal inhibition after 12 hour immersion and other extracts could not exceed 60% inhibition after any exposure time.
Conclusion: The present study concludes disease found in Dendrobium orchid was caused by F. proliferatum and Methanol extracts of Sweet flag contain antifungal constituents for the control of F. proliferatum.

Open Access Original Research Article

Epidermal and Cytological Studies on Cultivars of Xanthosoma (L.) Schott. and Colocasia (L.) Schott. (Araceae)

Julian O. Osuji, Prince C. Nwala

International Journal of Plant & Soil Science, Page 149-155
DOI: 10.9734/IJPSS/2015/12589

Epidermal and cytological studies were carried out on the cultivars of Colocasia and Xanthosoma species to determine their taxonomic value within and between the accessions. Upper and lower epidermal membranes of the leaves were peeled and stained with 0.1% safranin solution. Young healthy roots (about 15mm long) were obtained and fixed in 3:1 ethanol: acetic acid for about 18-24 hours and stored in 70% ethanol. The root tips were squashed in FLP Orcein and observed under the microscope. Stomata were found on both upper and lower epidermis of both Colocasia and Xanthosoma spp. but were more abundant on the lower epidermis of both species. Papillae were present on the lower epidermal cells of Xanthosoma but absent on the lower epidermal cells of Colocasia. Details of the ultra structure of the papillae showed that intraspecific variations occurred in the epidermis of these species. The epidermal variations in stomatal index within the Xanthosoma and Colocasia cultivars reflect their ecological adaptation to variation in the degree of wetness of the environment. All accessions of Xanthosoma gave the somatic chromosome count 2n = 2x = 24 while all Colocasia cultivars gave the somatic chromosome count 2n=2x=42. The chromosomes varied mostly from metacentric to subacrocentric in both species. These observations form part of the baseline data needed in planning their improvement and germplasm conservation.

Open Access Original Research Article

Soil Morphology, Physico - Chemical Properties and Classification of Typical Soils of Mwala District, Kenya

Anne N. Karuma, Charles K. K. Gachene, Balthazar M. Msanya, Peter W. Mtakwa, Nyambilila Amuri, Patrick T. Gicheru

International Journal of Plant & Soil Science, Page 156-170
DOI: 10.9734/IJPSS/2015/13467

A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its morphology, soil physico-chemical characteristics and to classify it using two internationally known soil classification systems. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Soil morphological observations revealed that the pedon is well drained and very deep with dark brown to dark yellowish brown topsoil overlying brown to strong brown sandy clay loam to sandy clay subsoil. Clay eluviations - illuviation is a dominant process influencing soil formation in the study area as indicated by the clay gradient between the eluvial and illuvial horizons and the presence of clay cutans in the subsoil. The soil is characterized by weak fine subangular blocky throughout its pedon depth. Laboratory analysis indicates that the soil is very strongly acid (pH 4.6–5.0) throughout the profile, has very low N (<0.1%) and low OC (0.6-1.25%). The pedon has low CEC (6.0-12.0 cmol (+) kg-1) and low base saturation (<50%). Available P is rated as high (>20mg kg-1) in the topsoil while it is low (7-20mg kg-1) in the major part of the subsoil. Using field and laboratory analytical data, the representative pedon was classified to the subgroup level of the USDA Soil Taxonomy as Typic Haplustults and to Tier-2 of WRB as Haplic Cutanic Acrisols (Humic, Hyperdystric, Endosiltic). The general fertility of the soils of the area is discussed highlighting their potentials and constraints.

Open Access Original Research Article

Irrigation Scheduling Effects on Components of Water Balance and Performance of Dry Season Fadama-Grown Pepper in an Inland-Valley Ecosystem in a Humid Tropical Environment

S. O. Agele, A. Y. Anifowose, I. A. Agbona

International Journal of Plant & Soil Science, Page 171-184
DOI: 10.9734/IJPSS/2015/6870

This study examined the contribution of water table via capillary rise and irrigation, to soil moisture storage and water use of pepper (Capsicum annuum var. Tatase), grown in an inland valley swamp (flood plain) in the dry season in a humid zone of Nigeria. The contribution of water table (capillary rise/upflows: Cg) to root zone moisture was quantified based on the soil water balance. Capillary rise was taken as the difference between estimated crop evapotranspiration (ETa) and measured soil water depletion (SWD). Irrigation regimes consisted of water application at weekly (7-day) and fortnight (14-day) interval using gravity-drip system. In the respective 7-day and 14-day irrigation intervals, shoot biomass were 153 and 141g plant-1 while fruit yields were 8.6 and 7.9 t ha-1 which constituted about 8.2% yield reductions were obtained under 14-day compared with 7-day irrigation. Capillary rise ranged from 2.3 to 5.2 mm which amount to 81 and 124% of pepper evapotranspitaion (ETa) across the sampling periods. The results showed that the weekly and fortnight irrigation intervals produced seasonal ET were 109 and 83 mm, soil moisture contents of 201 and 164 mm within crop root zone and water use efficiencies of 0.14 and 0.19t/ha/mm. Soil moisture storage and its depletion, Cg, crop evapotranspiration (ETa) and relative water use (ETa/Eo) differed in the growth stages of pepper, were influenced by irrigation regimes, groundwater table depth, and the prevailing weather conditions (vapour pressure deficit, temperature, thermal time) during pepper growth. Seasonal trends of the relative water use indicate the inability of soil moisture storage to satisfy pepper water requirements (ETa). Weekly irrigation offered the best compromise in the circumstance of declining water table depths and high climatic demand of the dry season in the site of study. Results show that irrigation regimes imposed optimized the contribution of groundwater to soil moisture storage and water use of pepper.

Open Access Original Research Article

Comparison of Organic Nutrient Sources with NPK for Cashew Seedlings Growth towards Organic Cashew Farming in Nigeria

Rotimi Rufus Ipinmoroti, Olorunfemi Sunday Ojo Akanbi

International Journal of Plant & Soil Science, Page 185-191
DOI: 10.9734/IJPSS/2015/11581

As a preliminary effort to commence organic cashew farming in Nigeria, a study to assess the growth performance of cashew seedlings was conducted in two consecutive trials using four organic nutrient sources namely cow dung, poultry droppings, cocoa pod husk and kola pod husk compared with NPK (15:15:15) and control - without fertilizer. The trial was conducted in the greenhouse at Cocoa Research Institute of Nigeria, Ibadan, in a completely randomized design with 4 replications. Data on agronomy parameters and dry matter yield after 6-months of planting were taken and statistically analyzed using ANOVA and significant mean differences were separated by LSD at p<0.05. Cashew seedling growth performance was significantly (p<0.05) influenced by fertilizer application over the control in both trial periods. The plant root growth was significantly (p<0.05) better with organic nutrient sources compared to NPK. Cashew seedlings leaf, stem and root dry matter yield values were least in control treated plants and highest for poultry droppings. Similar trend but with higher values of 7.7-23.5% were obtained at the 2ndtrial than for 1st trial for the fertilizer treated cashew seedlings, while it was reduced by 6.56% for the control. On the overall, the fertilizer treated cashew seedlings had significantly (p<0.05) higher dry matter yield of 60.4 - 117.4% compared with the control plants. The organic fertilizers were superior to NPK while the organic fertilizers of animal origin were superior to those of plant origin.

Open Access Original Research Article

Comparative Effects of Lime and Phosphorus Sources on Nutrients Uptake and Yield of Maize in a Tropical Ultisol

M. O. Adorolo, B. O. Okonokhua, E. A. Akinrinde

International Journal of Plant & Soil Science, Page 140-148
DOI: 10.9734/IJPSS/2015/12850

Ultisols are acid forest soils of low fertility status formed from intense weathering and leaching processes in the humid temperate and tropical regions. Sustainable crop production on these soils where phosphorus (P) deficiency is a main constraint aims at maintaining high crop yields by enhancing nutrients availability and uptake efficiency. This study was carried out at the Faculty of Agriculture, University of Ibadan to compare nutrients uptake and yield among maize plants grown from an ultisol with either sole or combined amendments of lime (L), rock phosphate (RP) and organomineral fertilizer (OMF). Eight treatment combinations: control, L, RP, OMF, L+ RP, L+OMF, RP+OMF and L+RP+OMF, each supplying 200kg P/ha and/or 1.0t/ha of L were replicated three times in a Complete Randomized Design. Crops grown in the RP+OMF amended soil (AMS) took up the highest concentrations of Ca, Zn, Mn and Fe. These were followed by the uptake of Ca and Mn from the L+RP AMS with the highest uptake of Mg. Next were those produced from the OMF AMS for Mg, Ca, Mn with the uptake of Zn and Fe only second to those in the RP+OMF AMS. Maize produced at 4 weeks after sowing from the OMF and L+RP AMS took up relatively higher concentrations of P, and together with those raised in the RP+OMF AMS which had the heaviest significant (P≤0.05) fresh root weight, produced the most significant height, leaf area and fresh shoot weight. The concentrations (1.10g/kg) of the dried shoot weight of the OMF and L+RP AMS were significantly higher than those of the other AMS, besides that of the RP+OMF (0.98g/kg). Tropical ultisols could be amended with OMF, RP+OMF or L+RP for effective nutrient uptake and maize yield.

Open Access Original Research Article

Study of the Influence of Previous Vegetation and the Induction of Immunization of Oil Palm (Elaeis guineensis) against Fusarium Wilt

Gbongué - Louis Raymond, Diabaté Sékou, Dick Acka Emmanuel, Yté Wongbé

International Journal of Plant & Soil Science, Page 192-202
DOI: 10.9734/IJPSS/2015/10358

Study Design: One of the major challenges in the control of oil palm Fusarium wilt at prenursery stage for seedlings protection by pre-inoculation with a saprophytic strain of Fusarium oxysporum lies in the persistence of the defence induced under a high parasitic strain‘s pressure characterizing old oil palm plantations areas at replanting.
Place and Duration of Study: Prenursery area of the National Center for Agronomic Research (CNRA), research station Robert Michaux of Dabou and oil Palm Physiology and Pathology Laboratory, between October 2009 and May 2010.
Methodology: The assessment of the influence of the Fusarium wilt history of an oil palm plantation on the acquisition of protection by the next generation of oil palms was performed on 2-months-old oil palm seedlings, sensitive to Fusarium wilt and growing on three types of soils characterizing the different Fusarium wilt history.
Results: The protection inducing treatment, characterized by the pre-inoculation of the non-pathogenic strain of Fusarium oxysporum (Fot) in the root system before the inoculation of the pathogenic strain F. oxysporum f. sp. elaeidis (Foe), has reduced the number of diseased seedlings at a rate of 24% against 35% when only the pathogenic strain Foe was inoculated in the seedlings, independently of the type of soil. Nevertheless, the expression of Fusarium wilt was delayed for a few weeks, only on the extension soil, and only in the case of pre-inoculation with Fot.
Conclusion: The biological control of oil palm Fusarium wilt at prenursery stage can only be, for the moment and under the conditions specified herein, rationally envisaged in new areas and not in replanting of old oil palms’ areas.