Open Access Original Research Article

Exogenous Cytokinin Promotes Epipremnum aureum L. Growth through Enhanced Dry Weight Assimilation rather than through Changes in Partitioning

A. Di Benedetto, C. Galmarini, J. Tognetti

Journal of Experimental Agriculture International, Page 419-434
DOI: 10.9734/AJEA/2015/13398

Aims: Benzylaminopurine (BAP) sprays have been shown to increase leaf size and leaf appearance rate, as well as biomass accumulation in pot-grown Epipremnum aureum L. BAP-mediated enhanced growth could either be the consequence of a higher investment of dry weight in leaf area development thus leading to a positive dry weight accumulation feedback, to a promoting effect on dry weight assimilation per unit leaf area.

Study Design: A randomized complete block factorial design with three blocks was used.

Place and Duration of Study: Two experiments were carried out in a greenhouse at the Faculty of Agronomy, University of Buenos Aires, Argentina (34°28’S) from the 8th September 2007 and 5th September 2008, respectively, to the 12th March 2008 and 11th March 2009 respectively.

Methodology: We analyzed the effect of exogenous BAP supplied in different number of applications and at different concentrations under three light intensities, on dry weight accumulation and partitioning in E. aureum grown in pots, in two greenhouse experiments.

Results: A single 5mg L-1 BAP application was enough to increase the dry weight accumulation rate in comparison to untreated controls, irrespective of the light intensity. A strong direct relationship between the relative growth rate (RGR) and the net assimilation rate (NAR) were found, while an inverse relationship was observed between RGR and the leaf area ratio (LAR). Even though BAP increased dry weight partitioning to the aerial part, as revealed by shoot vs. root allometric analysis, this did not result in a LAR increase, but rather in higher stem dry weight accumulation, in association with a decrease in the leaf area partitioning coefficient (LAP). NAR promotion by BAP was associated with an increased N content per unit leaf area, rather than with changes in chlorophyll content.

Conclusion: Our results on the ornamental shade plant E. aureum also provide information which may help to increase productivity to this crop from a grower perspective.

Open Access Original Research Article

Yield Traits and Water Productivity Responses among Rice Varieties (Oryza sativa L.) Grown in A Fadama Ecosystem in Akure, Southwestern Nigeria

S. O. Agele, A. T. B. Aderibigbe, T. O. Oladitan

Journal of Experimental Agriculture International, Page 435-449
DOI: 10.9734/AJEA/2015/6197

Drought is the most important factor limiting rice productivity under rainfed system of the humid tropics. Field experiments were conducted to determine the effects of soil water management strategies (growth on residual soil moisture at the vegetative stage supplemented with irrigation at the reproductive stage and growth under full irrigation throughout) on water use, yield and yield components of four varieties of rice grown in the dry season in an inland valley swamp (fadama). The four selected varieties were two upland (Ekpoma local and upland Nerica 4) and two lowland (lowland Nerica 1 and 2). The first planting (December, 2010) adequacy of soil moisture from planting to date of first flowering was assumed, thereafter irrigation was imposed during reproductive growth. In the second sowing (Janaury, 2011), rice plants were drip-irrigated from planting to seed harvest. The results indicated that differences between the December and January sowing dates were found  significant for most of the traits measured (root and shoot weight, leaf area, plant height, number of tillers, weights of panicle and 100-seed and harvest index). Total seed yield and harvest indices (3.19 t ha-1:10.1) were higher in January over December (1.24 t.ha-1: 6.3) sowing in addition to higher water use efficiencies (0.053 and 0.031 The seed yield reduction was associated with reductions in plant height (103.4:76.8 cm), leaf area (51.9: 76.1 m2) and shoot weight (103.7: 76.8 g) across all tested lines. Seasonal soil moisture storage ranged from 186 to 223 mm for the respective first (December) and second (January) sowing dates. The two best lines (Upland cultivars: Ekpoma and Nerica 4), had similar yield performance when grown under irrigation from planting to maturity (harvest) but differed significantly in their trait combinations. Over other varieties, upland Ekpoma and Nerica 4 exhibited superior ability to produce tillers, panicle and seed weights in both first and second sowing dates. Functional relationships between some weather variables and growth and yield characteristics of rice which gave high regression coefficients (R2) showed that, the differences in shoot biomass and seed yield production between the sowing dates were explained by a combination of weather parameters.  The evaluated varietal yield potential and related traits measured under variable soil moisture regimes were discussed in relation to genotypic adaptation (drought tolerance) among the tested rice varieties. It is concluded that, in a cultivar, higher yield potential may be related to ability to tolerate multiple and concurrent abiotic stresses of soil and air moisture deficit and temperature stresses.

Open Access Original Research Article

Effect of Different Types of Mulching and Plant Spacing on Weed Control, Canopy Cover and Yield of Sweet Potato (Ipomoea batatas (L.) Lam)

S. M. Laurie, M. N. Maja, C. P. Du Plooy

Journal of Experimental Agriculture International, Page 450-458
DOI: 10.9734/AJEA/2015/12404

The aim of the study was to determine the effects of mulching, plant spacing and other control measures on effectiveness of weed control, canopy cover and sweet potato yield. The cultivar Blesbok was planted in a randomized complete block design where seven treatments were replicated four times. Field trials were established at the Agricultural Research Council - Roodeplaat Vegetable and Ornamental Plant Institute in Pretoria, South Africa during 2006 and 2007. Seven treatments were applied: 1) HW = Hand weeding, 2) NS = Narrow plant spacing (0.5 m between the rows and 15 cm between plants), 3) CO = Organic mulch (compost), 4) PL = Inorganic mulch (black plastic), 5) E*F = Eptam (EPTC; Thiocarbamate) followed by Fusilate (fluazifop-p-butyl), 6) L*F = Afalon (Linuron) followed by Fusilate (fluazifop-p-butyl), and 7) CN = Control (untreated plot). Organic mulch (compost) was omitted in the second trial as it will be beneficial for both weeds and the crop making it difficult to control the weeds. Instead, grass straws (ST) and newspaper (NP) mulches were added. Narrow row spacing, hand weeding, plastic mulch, and newspaper mulch outperformed the other treatments and obtained more than 90% canopy cover by 5 weeks after planting. Effective reductions in weeds were detected with plastic and newspaper mulched plots and was similar to the hand-weeded treatment, followed by narrow spacing. Plots with newspaper mulch and narrow spacing produced marketable yields similar to the hand-weeded treatment. Inorganic mulching and narrow plant spacing were the most effective weed management treatments. Newspaper mulch seems to be a viable option for small holder farmers to control weeds in sweet potato plantings, eliminating the cost of labour to conduct hand weeding. Compost and grass mulch should not be adopted for weed control since these did not control weeds effectively.

Open Access Original Research Article

Percentage Yield Difference, an Index for Evaluating Intercropping Efficiency

A. I. Afe, S. Atanda

Journal of Experimental Agriculture International, Page 459-465
DOI: 10.9734/AJEA/2015/12405

Aim: To evaluate intercropping efficiency using percentage yield difference (PYD) and to    compare the index with other indices.

Study Design: The design was a 2 X 5 factorial in a randomized complete block design, and replicated three times.

Location: The study was carried out at the Lower Niger River Basin Development Authority, Ejiba (18°18°N, 5°39°E), Kogi State in the Southern Guinea Savannah Zone of Nigeria in 2008 and 2009 cropping seasons.

Methodology: Erect and prostrate cowpeas and maize were mixed at five population ratios. The five population ratios were: 100%C: 75%M, 100%C:50%M, 100%C:25%M, 75%C:25%M and 50%C:50%M (were C and M represented Cowpea and Maize respectively). Sole crops of each crop at full population were included as control treatments. Land Equivalent Ratio (LER), Area Time Equivalent Ratio (ATER), Monetary Equivalent Ratio (MER) and Percentage Yield Difference (PYD) were estimated and compared.

Results: Results of this study showed that LER, ATER, and PYD values were similar for the two cultivars in the two years.

LER values ranges between 1.18 and 1.27 in 2008 and 1.12 and 1.30 in 2009. MER did not follow the same trend as LER and ATER. Lower values were obtained particularly in 2009. However, the highest MER 1.35 and 1.23 in 2008 and 2009 respectively were obtained in prostrate cowpea / maize mixture at population ratio of 100:50. The PYD advantage varies between 5-33% in the two years.

Conclusion: The comparable values of PYD with other indices suggest that it can be used to evaluate/ intercropping efficiency in crop mixture.

Open Access Original Research Article

Adoption of Inorganic Fertilizer by Urban Crop Farmers in Akwa Ibom State, Nigeria

Nsikak-Abasi A. Etim

Journal of Experimental Agriculture International, Page 466-474
DOI: 10.9734/AJEA/2015/11553

This study was conducted between November, 2013 and April, 2014 in Uyo, the capital of Akwa Ibom State, Nigeria to empirically identify factors affecting the rate of adoption of chemical fertilizer by urban crop farmers. Through the multistage sampling procedure, 60 urban crop farmers were selected and interviewed with the aid of questionnaires. Data were analyzed using Tobit regression analysis. Results showed that the rate of chemical fertilizer adoption was positively and significantly related to land size, age, credit and education at (P<0.01) and (P<0.10) respectively, whereas average walking time to farm and soil fertility status were negatively and significantly related to fertilizer adoption and use intensity. This is an indication of the relevance of land, education and credit as determinants of technology adoption. It implies that the rate of adoption of fertilizer technology is strongly linked to these factors. Findings underscore the need to embark on market oriented interventions which will encourage urban farmers to adopt improved farming techniques as suitable policy decision. Enhancing human capital and availability of credit at lower cost are policy options that should be vigorously pursued.

Open Access Original Research Article

Evaluation of Sustainable Production Practices for Asian Vegetables (Luffa and Bitter Gourd) and their Mineral Nutrient Analysis in a Piedmont Soil of North Carolina

R. Ravella, M. R. Reddy, K. O. Taylor, M. Miller

Journal of Experimental Agriculture International, Page 475-481
DOI: 10.9734/AJEA/2015/11720

Aims: To reduce the inorganic fertilizers used to grow Asian vegetables (Luffa and Bitter gourds) by incorporating cover crops without compromising yield in piedmont soils of North Carolina

Study Design: A split-split plot design was used in this study with two main plot treatments and four rates of fertilizer as subplot treatments with four replications.

Place and Duration of Study: The study was conducted at the North Carolina A&T State University Farm, Greensboro, Guilford County, NC. from Fall, 2007 to Summer, 2008.

Methodology: Luffa (Luffa acutangula ‘Rama’) and bitter gourd (Momordica charantia ‘Comet’) were grown in a Mecklenburg Sandy Loam (fine, mixed, thermic ultic Hapludalfs) soil. Two cover crop treatments (Cover crop and no cover crop) and four fertilizer treatments (T1: 0-0-0, T2: 56-28-112, T3: 84-56-168, and T4: 168-112-224 N-P-K kg/ha) were studied to determine the yield of Asian vegetables in the Piedmont of North Carolina. The vegetables were hand harvested at weekly intervals for 9 weeks.

Results: Both luffa and bitter gourd yields increased with increase in rate of fertilizer. Cover crop treatment produced higher yields of luffa and bitter gourd compared to no cover crop treatment for all four fertilizer treatments. Statistical analysis has shown significantly higher yields (p=0.05) in T3 & T4 treatments for both luffa and bitter gourd.  Cover crop residue incorporated in to the soil decomposed and released nitrogen which was utilized by the vegetable crops and the effect was evident in increased yields in cover crop treatment plots.

Conclusion: Asian vegetables (luffa and bitter gourd) were grown in piedmont soils of North Carolina and the study showed that T3 & T4 treatments produced higher yields than all other treatments. This study provides evidence that Asian vegetables – such as luffa and bitter gourd – can be grown successfully in the piedmont region of North Carolina.

Open Access Original Research Article

Assessment of the use of Soil Improvement Management Practices among Arable Farmers in Egbedore Local Government Area, Osun State, Nigeria

A. O. Adekunmi, R. A. Oyeyinka, O. J. Yusuf

Journal of Experimental Agriculture International, Page 482-488
DOI: 10.9734/AJEA/2015/10921

The study assessed the use of soil improvement practices among arable crop farmers in Egbedore Local Government Area of Osun State, Nigeria. Primary data were collected from one hundred and twenty farmers randomly from six communities through the use of structured interview schedule. Data were analysed using descriptive statistics and correlation analysis. The results show that most of the farmers were between the ages of 21 and 60 years with mean age of 43.5. The large household size of respondents indicates that farmers depended more on family members for labour. The soil improvement practices which were mainly used by the respondents were: bush fallowing, mixed cropping, mulching, animal droppings and application of NPK fertilizer. The use of compost, superphosphates were not common among the arable crop farmers in the study area. Majority (72.5%) of the respondents preferred using planting systems as soil improvement practices. The .result of the correlation analysis shows that there was significant relationship between respondents’ farming experience, level of education and the use of soil improvement practices at P ≤ 0.05 and P ≤ 0.01 respectively. The numbers of soil improvement practices used was determined by the years of formal education and years of farming experience. There was a significant relationship between the level of skill and knowledge of respondents in any soil improvement practice (r = 0.772; P ≤ 0.01). This implies that the use of any of the soil improvement practice is determined by the level of knowledge and skill of the farmer on that practice. It was recommended that farmers should be trained enhancing skills and improving knowledge of different planting systems, preparation of organic practices and proper use of both organic and inorganic fertilizers.

Open Access Original Research Article

Direct Seeded and Transplanted Maize: Effects of Planting Date and Age of Seedling on the Yield and Yield Attributes

Mrityunjoy Biswas

Journal of Experimental Agriculture International, Page 489-497
DOI: 10.9734/AJEA/2015/13594

An experiment was conducted at the Bangladesh Agricultural Research Institute, Regional Station, Jamalpur, Bangladesh during rabi (winter) 2003-2004 to study the performance of maize varieties at different planting dates and ages of seedling. The experiment site is located at 24°56’11’’ N latitude and 89°55’54’’ E longitude and at an altitude of 16.46 m. The duration of the study period was November 2003 to May 2004. Design of the experiment was split-split plot having 3 (three) replications assigning planting date in the main plot (factor A), variety in the sub plot (factor B) and age of seedling in the sub-sub plot (factor C). Five planting dates (20 November, 30 November, 10 December, 20 December and 30 December), two maize varieties (BARI maize-6 and Pacific-11) and three ages of seedlings (Direct seeding, 14-day old and 21-day old seedlings) were included as treatments in the experiment. Seedlings were raised in the dry bed underneath polythene sheet nursery. The results revealed the variety Pacific-11 produced significantly higher grain yield in the earlier 20 and 30 November plantings irrespective of direct seeding and age of seedlings. There was no significant difference in respect of grain yield in the earlier 20 and 30 November plantings with all seedling ages but planting of 14-day old seedling the crop may be harvested about 7 days earlier, while planting of 21-day old seedling crop may be harvested about 12 days earlier than direct seeding. Transplanting of 14-day old seedling at 10, 20 and 30 December produced higher grain yield compared to both direct seeding and 21-day old seedling along with 5-6 days short field duration than direct seeding. This early harvest may save the crop from natural vulnerability of hailstorm and rains, and may help in early establishment of the next crop like sesame, aus rice, mungbean, blackgram, jute etc.

Open Access Original Research Article

Effect of Petroleum Products Treatment of Soil on Succinate Dehydogenase and Lactate Dehydogenase Activities in Cowpea (Vigna unguiculata) and Maize (Zea mays) Seedlings

F. I. Achuba

Journal of Experimental Agriculture International, Page 498-508
DOI: 10.9734/AJEA/2015/9989

Aim: Most of the land in oil producing area in the Niger delta region of Nigeria is under constant petroleum pollution exposing the soil to the deleterious effect of petroleum hydrocarbons. The effects of petroleum products (kerosene, diesel, engine oil and petrol) treatment of soil at various sublethal concentrations (0.0%, 0.1%, 0.25%, 0.5%, 1.0%, 1.5% and 2.0%) on succinate dehydrogenase and lactate dehydrogenase activities in the leaves of cowpea and maize seedlings were then studied.

Place and Duration of Study: This study was conducted in Delta State University, Abraka, Nigeria between April 2007 and August 2011.

Methodology: Improved varieties of maize (Zea mays) and Vigna unguiculata (L) Walp were planted in soil contaminated at different concentrations of six groups of five replicates. Groups 1 to 5 contained 0.1%, 0.25%, 0.5%, 1.0% and 2.0% (v/w) respectively of each of the petroleum products while group six served as control (0.0%). Three seeds were planted in each bag and watered daily.  The activities succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) in the leaves of the cowpea and maize seedlings were analysed after four, eight and twelve days after germination.

Results: The results indicated that petroleum products treatment of soil resulted in decrease in succinate dehydogenase activity in both cowpea and maize seedlings as well as a corresponding increase in lactate dehydrogenase activity in the two seedlings. The toxic effect of kerosene was more severe than the other products studied. Similarly, Cowpea seedlings were affected more than maize seedlings.

Conclusion: Generally, the data indicate that seedlings exposed to petroleum products treated soil tend to move towards anaerobic respiration in a bid to survive under petroleum stress.

Open Access Review Article

Nutritional Requirement and Management of Arabica Coffee (Coffea arabica L.) in Ethiopia: National and Global Perspectives

Abayneh Melke, Fisseha Ittana

Journal of Experimental Agriculture International, Page 400-418
DOI: 10.9734/AJEA/2015/12510

The bulk of coffee soils in southwestern and southern regions of Ethiopia are classified as Nitto sols, which are highly weathered and originate from volcanic rock. These soils are deep and well drained having a pH of 5-6, and have medium to high contents of most of the essential elements except nitrogen and phosphorus. Also, most of the coffee plantations are often managed with shade trees in small scale, with minimal fertilization; litter fall and decomposition play an important role in nitrogen cycling and maintenance of soil fertility. The amount of plant nutrient required by coffee trees may vary depending on several factors. the amount and  distribution of rainfall, the species and amount of other plants grown in association with the coffee trees, seasonal variation, topography,  soil type and the prevailing cultural practices. Proper coffee nutrition requires special attention of the grower because it affects bean size (grade), bean quality and the overall productivity of the crop that determines marketability. Nutrients are applied to replenish those that are lost through tissue formation, yields, leaching and those that form compounds where they cannot be easily extracted by roots. This calls for application of mineral fertilizers and/or organic manures so as to apply the necessary nutrients in the required amounts. As a result it was possible to come out with a set of recommendations that are of immense value to the growers. Therefore, the objective of this paper is to review the achievements and constraints of mineral fertilization and the potential to use of organic/bio-fertilizers for the present and future coffee production in Ethiopia.