Influence by artificial defoliation and NPK fertilizer application on growth and yield of Okra (Abelmoschus esculentus (L) Moench)

A field trial to determine the effect of artificial defoliation and NPK fertilizer application on growth and yield of okra was conducted in 2010 and 2011 at the Teaching and Research Farms of the Faculty of Agriculture, University of Benin, Benin City, Nigeria. Okra “Uselu Local” was sourced locally and subjected to four rates of NPK fertilizer (0, 200 (30 kg N, 13 kg P and 30 kg K ha-1); 400 (60 kg N, 26 kg P, 50 kg K ha-1), and 600 (90 kg N, 60 kg P, 90 kg K ha-1) kg ha-1) at different percentages (0, 25 and 50 %) of defoliation respectively at four and six weeks after sowing. The experiment was laid out as a randomized complete block design arranged in a split-split plot and replicated three times. Each replication was allocated 12 treatments with NPK fertilizer application as the main plot, defoliation (sub-plot) and time of defoliation (sub- sub plot). Data were collected on parameters such as days to 50 % flowering, plant height at which fresh pods were harvested, plant height at which dry pods were harvested, number of pods per stand, average pod weight, pod weight per stand, pod yield per hectare, pod diameter, number of dry pod per stand, number of seeds per pod and stand. Obtained data were analyzed using analysis of variance procedure for split – split plot design and means were compared using LSD at 5 % level of significance. Results obtained indicated that defoliation considerably affected plant height and days to 50 % flowering. The reduction in growth due to defoliation was observed to be significant at four weeks after sowing of okra. NPK fertilizer application significantly reduced the deleterious effects of defoliation with regards to plant heights, days to 50 % flowering and yield of okra. The NPK fertilizer application promoted vegetative growth to cushion the adverse effects of defoliation. The interaction between NPK fertilizer application and defoliation was only significant on number of seeds per pod. There were significant interactive effects between NPK fertilizer and time of defoliation on plant heights and number of seeds per pod. Increasing in NPK fertilizer application above 200 kg (30 kg N, 13 kg P and 30 kg K ha-1) NPK fertilizer ha-1 could be profitable and to bring about a considerable increase in the growth and yield of okra.Keywords: Defoliation, NPK fertilizer, okra, yiel

Effects of Spent Engine Oil Polluted Soil and Organic Amendment on Soil Chemical Properties, Micro-Flora on Growth and Herbage of Telfairia Occidentalis (hook f).

A trial was conducted at the Screen House of the Department of Crop Science, University of Benin, Benin City, Nigeria to evaluate the efficacy of using organic fertilizer as bioremediant for spent engine oil polluted soils. Three concentrations of spent engine oil (0, 5 and 10 % w/w, spent engine oil in soil) and three application rates of organic fertilize (0, 5 and 10 t ha-1) were utilized in a 3 x 3 factorial arrangement and laid out as a completely randomized design with three replication. Soil pH, available P and exchangeable cations were significantly reduced by spent engine oil except organic C compared to control. Heavy metals (Va and Pb) concentration increased with increasing concentration of spent engine oil. Amendment of spent engine oil polluted soil with organic fertilizer significantly remediated the degraded soil and decreases the heavy metal concentration. In addition, 10 t ha-1 organic fertilizer showed superiority over 5tha-1 organic fertilizer in amending spent engine oil degraded soil for pH, total N, available P, exchangeable Ca2+ and reduced heavy metal concentration. Soil pollution adversely affected number of leaves, dry vine weight, dry leaf weight and herbage yield. Growth and herbage yield were much higher in organic fertilizer amended spent engine oil polluted soil. the highest herbage yield (9.23 t ha-1) was obtained from unpolluted soil treated with 10 t ha-1 organic fertilizer which was statistically comparable with soil polluted with 5 % spent engine oil and amended with 10 t ha-1 organic fertilizer (7.10 t ha-1). Soils polluted with 5 % spent engine oil had higher bacteria population compared to control, while organic fertilizer had depressing effect on soil without spent oil pollution. However, unpolluted soiltreated with 10 t ha-1 organic fertilizer had the fungi (0.77 x 106cfu g-1) population which was statistically compared to 5 t ha-1 organically treated soil without spent engine oil pollution (0.76 x 106cfu g-1). Soil polluted with spent engine oil has been bioremediated with organic fertilizer and hence put into productive use.Keyword: Growth, herbage yield, micro-flora, organic fertilizer, spent engine oil, Telfairia occidentalis

Performance, Nutrient Uptake and Profitability of Amaranthus Cruentus (Linn.) in Response to Different Soil Amendments

Studies was conducted at the Teaching and Research Farms of Benson Idahosa University, Benin City, Nigeria in 2009 and 2010 to evaluate the effects of different soil amendment materials on some soil properties and performance in terms of nutrient content, uptake and proximate analysis of Amaranthus cruentus. The experiment, which was organized in a randomized complete block design, had three replications with control, organic fertilizer in two levels (20 and 40 t ha-1), inorganic fertilizer (NPK) and combined inorganic and organic fertilizer (organomineral fertilizer) at acombination of 20 t ha-1 organic fertilizer and 100 kg ha-1 NPK. Results showed that soil pH, organic carbon, total N, available P, exchangeable Ca, Mg and K were increased in through the incorporation of organic and organomineral fertilizers. However, soil pH and organic carbon contentwere reduced in NPK treated plots. Stem girth and plant height was highest with 40 t ha-1 organic fertilizer treatment at four weeks after transplanting. Mean leaf number, leaf area index (LAI) and total dry weight (TDW) followed similar pattern throughout the sampling periods. Fresh herbageyield was significantly influenced by soil amendments and the highest herbage yield (10.60 t ha-1) was obtained from 40 t ha-1 treatment. The NPK treatment produced the yield with the maximum nutrient content and uptake. The organomineral fertilizer treatment was the most expensive but the optimum yield was produced by 40 t ha-1 organic fertilizer treatment based on revenue (N530,000), gross margin (N439798.10), Net profit (N421675.39) and benefit-cost ratio (4.20) the among thetreatments