GROWTH AND YIELD OF Corchorus olitorius AS INFLUENCED BY PLANT POPULATION AND FERTILIZER TYPE IN THE HUMID ULTISOLS OF SOUTHWESTERN, NIGERIA.

Transcription

1 GROWTH AND YIELD OF Corchorus olitorius AS INFLUENCED BY PLANT POPULATION AND FERTILIZER TYPE IN THE HUMID ULTISOLS OF SOUTHWESTERN, NIGERIA. ABSTRACT Law-Ogbomo *, K. E. and Osaigbovo, A. U. Department of Crop Science, Faculty of Agriculture, University of Benin, PMB 1154, Benin City, Nigeria This experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture, University of Benin, Benin City, Nigeria, between from April and August, 2013 and 2014, to evaluate the effect of fertilizer types and plant population on the growth and yield of Corchorus olitorius. The 3 x 4 factorial experiment involving three plant populations (100,000; 200,000 and 400,000 plants per hectare (pph) and four fertilizer types (control, goat, poultry and NPK) was laid out in in randomized complete block design with three replications. Data were collected on plant height, number of branches and leaves, leaf area index, dry matter and herbage yield as well as the economic analysis. Routine analysis of the soil indicated that the soil was low in nutrient content and application of fertilizer to the soil enhanced the growth and herbage yield. However, increasing plant population and fertilizer application increased variable cost. The optimum herbage yield was observed from the population of 200,000 plants per hectare treated with goat, since, it had the highest gross margin and return per naira invested with N 983,900 and 3.32, respectively. Keywords: Economic analysis, herbage yield, leaf area index, low soil native fertility. INTRODUCTION The yield of Corchorus olitorius, is dependent on soil fertility and plant density. However, most soils in humid tropics are intensely weathered, leached and intensively cultivated leading to impoverished soil (Akanbi and Togun, 2002). Hence it lacks the capacity to support plant growth to produce optimally. The inherently low fertility status of the soil had resulted in poor crop performance in the field. However, low plant population without soil amendment among other husbandry activities employed in the cultivation of C. olitorius had resulted in low yield per unit area. These constraints necessitated the need for appropriate management techniques to improve soil fertility and utilize appropriate plant population in order to increase crop yield. There is an important need to increase yield per unit area through the application of organic and / or inorganic fertilizer. Leafy vegetables responded positively to plots that received NPK fertilizer giving rise to better yields than non-fertilized plots (Law-Ogbomo and Ekunwe, 2011). However, the limited use of inorganic fertilizer by farmers is attributed to scarcity, high cost, it does not improve soil tilt and its long-term usage has resulted in soil nutrient imbalance (Adeniyan and Ojeniyi, 2005). This necessitates research on the use of organic fertilizers that are cheap, readily available and environmentally friendly (Ayeni, 2010). Animal (goat, cattle, poultry, pig, etc.) faeces are organic materials high in nutrients (Gupta et al, 2004). Composted animal faeces contained beneficial bacteria which convert nutrients into easily accessible form that can be moderately released for the plant uptake. They can also help to reverse global warning by reducing greenhouse gases, improving energy-efficiency and significantly increasing carbon sequestration in soils (Aiyelaagbe, 2011). Animal wastes are abundant in livestock farms and market as waste products and constitute nuisance to the environment. The conversion of these wastes to soil amendment will decrease pollution and hazard posed by poor animal waste disposal. Long term use of animal s will lead to improved soil aggregate stability, poor space, bulk density and water holding capacity (Vanlauwe et al., 2001). Guptal et al. (2004) reported a significant yield increase of sugar cane as a result of cattle dung application through increase in organic matter, cation exchange capacity and ph. Cattle dung utilized as soil amendment has been found to increase soil carbon, inorganic N and exchangeable cations. Appropriate plant population optimized light interception to favour higher yield production. Generally, increase in plant population had resulted in increased yield per unit area up to certain limit (Weiner, 1990). Crop yield per stand decreased with increasing plant population. This is attributable to inter- and intra-specific plant competition for growth resources. Information on the usage of different fertilizer sources for C. olitorius and appropriate plant population to maximized yield is lacking. Hence the aim of this trial was to evaluate the effect of plant population and fertilizer type on the growth and herbage yield of C. olitorius. MATERIALS AND METHODS The experiment was conducted at the Teaching and Research Farm of the Faculty of Agriculture, University of Benin, Benin City, Nigeria, between April and August in both 2013 and The location lie on Latitude 8 10' NJAFE VOL. 12 No. 1,

2 N and longitude 4 10' E and elevation of approximately 152 m. Corchorus olitorius ( ewedu ) ''Uselu'' local cultivar was bought from Edaiken Market, Uselu, Benin City. and goat s obtained from the University of Benin commercial farms were cured under shade and applied to plots as per treatment. Application was done four weeks before transplanting of seedlings for equilibration while NPK was applied to plots as per treatment one week after transplanting. Prior to application of fertilizer and transplanting, composite soil sample was taken from the site and analysed in the laboratory using standard laboratory procedures. Accordingly, determination of soil particles size distribution was carried out using the hydrometer method. Soil ph was measured potentiometrically using digital ph meter in 1:2.5 soil to solution ratio with water and IM KCl solution. Exchangeable bases were extracted with 1.0 M ammonium acetate at ph 7.0, calcium and magnesium in the extract was measured by atomic adsorption spectrometer while K was determined using flame photometer. Organic carbon was determined following wet digestion method as described by Walkey and Black (1934). Total nitrogen in soils was determined by the Kjeldahl procedure as described by Jackson (1963). Available P in soils was determined by the Olsen (Olsen et al., 1954) and Bray II (Bray and Kurtz, 1945) methods. The cured s were also analysed for their chemical composition. The experiment was laid out in a randomized complete block design (RCBD) with three replicates in a 3 x 4 factorial arrangement. The factors were plant population at three levels (100,000, 200,000 and 400,000 plant per hectare (pph) and four fertilizer types (control (untreated), goat,, poultry and NPK), the organic were applied four weeks before transplanting at 15 t ha -1 while NPK was applied 7 days after transplanting at 400 kg ha -1 as side dressing between the row of C. olitorius. Corchorus seeds were subjected to hot water treatment for 20 seconds and then dried under shade overnight. After which they were mixed with sand and broadcast in the nursery. They germinated within three days and remain in the nursery for three weeks while in the nursery, routine maintenance practice carried out were hand weeding, rogueing and watering. At the end of three weeks in the nursery, the seedlings were transplanted to the experimental site at the spacing of 100 x 10 cm, 100 x 50 cm, 50 x 5 cm giving a plant population of 100,000 pph, 200,000pph and 400,000 pph respectively. Adequate weeding was carried out when necessary. Insecticidal neem spray and rogueing of diseased plants were also carried out when necessary. A total of five randomly selected plants per plot were tagged as sample plants for observation and data collection. Data collections were on plant height, number of branches per plant, number of leaves per m 2, leaf area m 2, leaf area index (LAI) and dry matter yield m 2 at six and eight weeks after transplanting (WAT). At harvest, five inner Corchorus plants were randomly uprooted, the root cut off and succulent plant parts were weighed on the sensitive scale and expressed in tonnes per hectare (t ha -1 ). Data collected were subjected to analysis of variance using GENSTAT statistical package (GENSTAT, 2005). Significantly, different means were separately, using the least significant difference (LSD) at 5 % level of probability. The optimum plant population and fertilizer type was obtained through profitability analysis of Corchorus production among plant population and fertilizer types. The gross margin is the difference between return (R) and total variable cost (TVC) (Erhabor, 2005). The total variable cost (TVC) includes items like total cost of labour (land preparation, planting, transplanting, weeding, fertilizer application and harvesting), Fertilizer, planting materials and transportation. Return per naira invested = Revenue TVC RESULTS Physical and chemical properties of the experimental site The result of the soil analysis of the experimental site before cropping with C. olitorius is presented in Table 1. The soil was sandy loam with inadequate organic matter content, total nitrogen and available phosphorus. Table 2 revealed that poultry and goat s contained high amount of organic carbon and appreciable quantities of total nitrogen, available phosphorus and magnesium. Growth Parameter Table 3 shows the growth parameter of C. olitorius in response to plant population and fertilizer application six WAT. Plant population did not significantly affect plant height and number of branches. However, number of leaves, LAI and dry matter were significantly different as a result of the effect of different plant populations. Increase in plant population increased number of leaves and dry matter. The highest pph (400,000) had the highest number of leaves per m 2 (3304), LAI (10.48) and dry matter (DM) (5464 gm -2 ) at 6 WAT. Plants treated with poultry, goat and NPK were significantly taller than the control. The tallest plants were observed in plants treated with poultry. However, poultry treated plants were not significantly taller than goat treated plants. The number of branches varied from 8-16 for untreated plants and plants treated with goat, respectively. All treated plants had higher number of branches than the control. The distribution trend of number of branches was reflected in number of leaves, LAI and DM. However, poultry and goat NJAFE VOL. 12 No. 1,

3 treated plants were similar. There were significant interaction effects between plant population and fertilizer application for number of leaves, LAI and dry matter at 6 WAT. Effects of plant population and fertilizer application on the growth of C. olitorius at 8 WAT is presented in Table 4. Plant population had significant effect only on LAI and dry matter and not on plant height, number of branches and number of leaves. LAI followed a definite trend with plant population. The plant population per hectare of 400,000 had the highest LAI with average of while the least was 100,000 pph with a mean value of Dry matter increased as plant population increased. Plant that grew at 400,000 pph had the highest dry matter ( g m -2 ) and the lowest was gm -2 obtained from 100,000 pph. Fertilizer application had significant effects on plant height, numbers of branches and leaves, LAI and dry matter at 8 WAT. Tallest plants were observed in plants treated with poultry (83.20 cm), which were comparable to plants treated with goat (80.20 cm). This trend was also observed in number of branches, number of leaves and LAI. However, dry matter was most accumulated in goat treated plants which was comparable to poultry. There were significant interactions between plant population and fertilizer application on number of leaves, LAI and matter. Table 1: Physical and chemical properties of the experimental site before cropping with Ewedu (Corchorus olitorius) Parameter Value Sand (g kg -1 ) Silt (g kg -1 ) Clay (g kg -1 ) Textural Class Sandy loam ph 5.24 Organic Carbon (g kg -1 ) Organic Matter (g kg -1 ) Total Nitrogen (g kg -1 ) 0.98 Available Phosphorus (mg kg -1 ) 6.43 Exchangeable cation (cmol kg -1 ) Calcium 0.92 Potassium 0.75 Magnesium 0.56 sodium 0.69 Exchangeable acidity(h + + Al 3+ ) 0.60 Effective cation exchange capacity 3.52 Table 2: Chemical composition of organic s Parameter Organic Goat ph Organic carbon (%) Total nitrogen (%) Available phosphorus (%) Magnesium (%) Potassium (%) Table 3: Effect of plant population and fertilizer type on the growth of C. olitorius at 6 WAT Treatment Plant height No. of Branches No. of Leaves LAI Dry Matter (cm) Plant -1 m -2 (g m -2 ) Plant population (pph) LSD(0.05) ns ns Fertilizer type Control Goat NPK LSD(0.05) Interaction ns Herbage yield of Corchorus olitorius The effect of plant population and fertilizer application on C olitorius is presented in Table 5. Increase in plant population resulted in definite distribution trend in herbage yield per Plant -1. Herbage yield per plant was highest in 200,000 pph ( g) and 100,000 pph (80.60 g) and lowest in 400,000 pph (55.50 g). Herbage yield per hectare (t ha -1 ) increase with increasing plant population and decreased at the highest plant population. The difference among plant population was significant and the highest was obtained from 200,000 pph with t ha - 1 while the 100,000 pph had the least (herbage yield per hectare with 9.60 t ha -1 ). However, 200,000 pph and 400,000 pph were comparable. NJAFE VOL. 12 No. 1,

4 Fertilizer application enhanced herbage yield per plant. The highest herbage yield per plant ( g) was produced from plants treated with goat and least herbage yield (50.00 g) was produced from plants without fertilizer treatment. However, all fertilizer treated plants produced similar herbage yield per plant. Plots fertilized with goat had the highest hectare yield (23.40 t ha -1 ) which were not significantly higher than other plots fertilized with poultry (16.30 t ha -1 ) and NPK () but significantly higher than unfertilized plots (19.60 t ha -1 ). There were significant interactions between plant population and fertilizer type on herbage yield. The highest herbage yield per hectare (31.30 t ha -1 ) were observed from 200,000 pph treated with goat. Table 4: Effect of Plant Population and Fertilizer Application on the Growth of C. olitorius at 8 WAT Treatment Plant height No. of Branches No. of Leaves LAI Dry Matter (cm) Plant -1 m -2 (g m -2 ) Plant population (pph) LSD(0.05) ns ns Fertilizer type Control Goat NPK LSD(0.05) Interaction ns ns Table 5: Effects of plant population and fertilizer type on the herbage yield of C. olitorius Herbage yield (g stand -1 ) Herbage yield (t ha -1 ) Plant population Fertilizer type Fertilizer type (pph) Control Goat NPK Mean Control Goat NPK Mean Mean LSD (0.05) Plant population LSD (0.05) Fertilizer type Interaction Profitability analysis of fertilizer type and plant density on Corchorus olitorius Total variable cost increased with fertilizer application and also with plant population and ranged from N357, 600 and N518, 100 (Table 6). The revenue and gross margin followed the same trend. However, the population of 200,000 pph treated with goat had the highest gross margin and return per naira invested with N983, 900 and 3.32 respectively (Table 6). DISCUSSION The main problems among others facing the production of C. olitorius in Africa despite its useful in terms of nutrition, health and industrial raw material are low fertility status of the soil and inappropriate plant population. In this trial, herbage yield was increased through higher plant population and fertilizer application. The soil used was a typical ultisol (acid sand) with low nutrient content and low effective cation exchange capacity. This observation re-affirmed the report by Akanbi and Togun (2002) that most of African soils are impoverished. The soils deficiency in plant nutrients arose from socio-economic and demographic factors that resulted to competition which continues to deprived agricultural sectors of arable land. This situation provided avenue for the continuous cultivation of available land which has resulted in depletion of soil fertility. The low organic carbon content is an indication of poor water and nutrient retention. Sustainable production of leafy vegetable on this site is impossible without the application of fertilizer as proven by the herbage yield of vegetable in the control plot (fertilizer was not applied). Fertilizer is any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to the soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment by Stewart et al. (2005) found out that about 40 to 60% of crop yields are attributed to commercial fertilizer use. This increase in crop yield is attributed to the nutrient content of the fertilizers used. Adeyeye (2009) reported that organic helps to improve the physical NJAFE VOL. 12 No. 1,

5 condition of the soil in addition to being a major contributor of plant nutrients. The results showed that the organic s used contain the essential nutrients needed by plants in appreciable quantities. Corchorus plant in this Table 6: Profitability analysis of the effect of plant population and fertilizer type on the herbage yield of C. olitorius Item 100,000 plants per hectare 200,000 plants per hectare 400,000 plants per hectare (N) Control Goat NPK Control Goat NPK Control Goat NPK Total variable cost 357, , , , , , , , , , , ,100 Yield (t ha -1 ) Revenue 355, , , , ,500 1,408, ,500 1,026, ,500 1,399, ,000 1,147,500 Gross margin (-2100) 27, , , , , , ,900 34, , , ,400 Return per naira invested trial showed promising result in response to fertilizer application in improving its productivity as the herbage yield was reduced where fertilizer was not applied at all. This may be related to insufficient nutrient uptake as plants have to rely on the fertility of the soil which has been shown to be poor. Increasing plant population per hectare resulted in the increase in the number of leaves. This was due to additional number of plants in a given area leading to additional of leaves being produced from the extra stands. However, without corresponding increase in fertilizer application, the leaves produced will be of small size. However, fertilizer application will lead to the production of leaves of appropriate sizes. Changes in the number of leaves are bound to affect the general plant growth and vigour as they are the major organs of photosynthesis for the plant (Law-Ogbomo and Remison, 2009). Increase in number of leaves is a precursor to increase in LAI. This is advantageous because a quicker canopy cover would suppress weeds thus enabling a higher yield. LAI is commonly used to determine the probability of light interception in relation to crop canopies (Keating and Carberry, 1993). An increased LAI enhanced photosynthetic capacity due to better utilization of solar radiation and hence increased fresh yield per hectare (Law-Ogbomo and Remison, 2008). Herbage yield per plant decreased with increasing plant population, a consequence of increased intra-row competition. On the contrary, lowering plant population produced higher herbage yield per stand. This connotes that plant density can be used effectively to alter leaf yield of C. olitorius. This is in agreement with Muoneke and Asiegbu (1996) who reported significant decrease in the yield components including okra pod yield per plant as plant density increased. However, a combination of fertilizer application and increasing population increased yield. The significantly increased herbage yield through increasing plant population and fertilizer application would enhance ewedu production and farmers income. Return per naira invested was greater than 1.00 at all plant density and fertilizer type combinations indicating that the enterprise is viable. The population of 200,000 pph treated with goat had the highest return per naira investment of This implies that maximum yield does not indicate maximum profit per amount of money invested (Doll and Osarem 1957). These findings also imply that profitable crop production depends on adequate essential nutrients and plant density but not excessive plant stands. CONCLUSION AND RECOMMENDATION This study revealed that ewedu production can be increased to ensure food sustainability through appropriate plant population and fertilizer application. In this study, the optimum herbage yields (31.3 t ha -1 ) with the highest return per naira invested (3.32) was produced from the combination of 200,000 pph and 15 t ha -1 of goat. This combination is therefore recommended for ewedu growers in the humid ultisols of South-western Nigeria. REFERENCES Adediran, N. O. and Ojeniyi, S. O Comparative and effectiveness of different levels of poultry with NPK fertilizer on soil residual fertility status, nutrient uptake and yield of maize. Moor Journal of Agriculture, 2: Adeyeye, A. S Pod shattering attributes and responses of soyabean (Glycine max (L.) Merrill) to compost, nitrogen fertilizer and rhizobium inoculation. Ph.D Thesis in the Department of Crop Protection and Environmental Biology, University of Ibadan, Nigeria. Akanbi, W. B. and Togun, A. O The influence of maize stover compost and nitrogen fertilizer on growth, yield and nutrient uptake of Amaranth. Scientia Horticulturae, 93: 1-9. Ayeni, L. S Effect of Combined Cocoa pod ash and NPK fertilizer on soil properties nutrient uptake and yield of maize. Journal of American Science 6 (3) Bray, R. H. and Kurtz, L. J Determining of total organic and available forms of phosphorus in soil. Soil Science 39: NJAFE VOL. 12 No. 1,

6 Erhabor, P. O Economic analysis of proven technologies by ADPs to farmers from Technical Report. Project Coordinating Unit, 334. Doll, J. P. and Osarem, F Production economic theory with application. Macmillan Publisher, London. pp Genstat Gentstat Release 8.1. Statistical Software. VSN International Ltd, Rothamsted, UK. Jackson, M. C Soil Chemical analysis. Prentice Hall Inc, New York, USA 498 pp. Law-Ogbomo, K. E. and Ekunwe, P. A Growth and Herbage Yield of Celosia argenta as Influenced by Plant Density and NPK Fertilization in Degraded Ultisol. Tropical and Subtropical Agroecosystems, 14, Law-Ogbomo. K. E. and Remison, S. U Growth and yield of maize as influenced by sowing date and poultry application. Notualae Botanicae Horti Agrobotanice Claj-Napoca, 37 (1): Law-Ogbomo, K. E. and Remison, S. U Growth and yield of white Guinea yam (Dioscorea rotudata poir)influenced by NPK fertilization on a forest site in Nigeria. Journal of Tropical Agriculture, 46 (1-2):9-12 Muoneke, C. O. and Asiegbu, J. E Effects of Planting Density on the Growth, dry matter accumulation, distribution and yield of okra in a tropical ultisol. Proceeding of the 14 th HORTSONS Conference. Ago- Iwaye, 1,-4 April, 1996 pp Olsen, S. R. Cole, C. V., Watanabe, F. S. and Dean, L. A. C Estimation of available phosphorus with sodium bicarbonate. Pp.1-19 USA Circular 939. Stewart, M. W., Dibb, W. D., Johnston, E. A. and Snryth, J. T The contribution of commercial fertilizer nutrients to food production. Agronomy Journal, 97: 1-6 Walkey, A. and Black, T. A An examination of the Degtajarest method for determining soil organic matter and proposed modification of chronic acid method. Soil Science 37:29-38 NJAFE VOL. 12 No. 1,