Effect of Sawmill Wastes, Animal Manure and N-P-K Fertilizer on the Performance of Okra (Abelmoschus esculentum) on an Alfisol

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1 Effect of Sawmill Wastes, Animal Manure and N-P-K Fertilizer on the Performance of Okra (Abelmoschus esculentum) on an Alfisol Abstract Aduloju, M. O., Fawole, O. B., Abubakar, A. J. and J. O. Olaniyan Department of Agronomy, University of Ilorin, Ilorin, Nigeria. Six organic materials: wood ash and saw dust (sawmill wastes); pullets droppings, pullets bedding, broilers bedding and cow dung (animal manure) were applied to an Alfisol to determine their potential as plant nutrient sources for Okra (Abelmoschus esculentum) in a pot experiment. The materials were applied at the rates of 0, 4 and 8 tonnes/hectare. These rates were compared with okra performance using inorganic NPK fertilizer at 80 kgn/ha., all in four replicates. Plant height, number of leaves, fruit length, fruit diameter and fresh fruit yields were recorded. The nitrogen (N), phosphorus (P) and potassium (K) contents of the various organic materials were also determined. Results showed that plant height, though highest with cow dung at 8 t/ha., and number of leaves, were not significantly affected; fruit diameter, fruit length and fresh fruit weight were all significantly(p<0.05) increased with increasing manure levels, regardless of the manure type. The lowest fresh fruit yield (10.1 g/pot) was obtained from pullets bedding while the highest (20.7 g/pot) was obtained from broilers bedding. All the manures except pullets bedding gave better fruit yields than fertilizer NPK, and 8 t/ha manure gave the highest fresh fruit yield. Keywords: okra, wood ash, saw-dust, poultry droppings 1. Introduction The scarcity of inorganic fertilizer, coupled with its high prices when available, has caused a lot of set-back to arable crop production in Nigeria. Animal and farmyard manure have been used to improve and supplement soil nutrients from time immemorial. However, the advent of inorganic fertilizer has almost eliminated the use of these manures by farmers as sources of plant nutrients and soil amendment because of its relative ease of application and quick results. A lot of organic manures lie waste in rural areas in Nigeria and even in developing urban centres and mega-cities like Lagos and Ibadan. They are usually dumped around farmsteads and saw-mills. Some of these organic wastes are burnt periodically while others are just dumped on the ground surface, increasing the problem of environmental pollution and constituting health hazards. Many farmers are so dependent on inorganic fertilizers that they have become helpless and unable to produce crops profitably when the fertilizers are not available or affordable. Many workers have tried to assess the importance of organic manures in crop production. Senjobi et al. (2010) reported that the use of poultry, plant and sheep/goat manures improved all the growth parameters of the leaf vegetable they worked with. Other workers have reported beneficial effects of organic manure on soil properties such as bulk density (Fawole et al, 2010); soil moisture content (Adeleye et al, 2010); water holding capacity and other soil physical properties (Fawole et al. 2010). 379

2 Many materials which are waste products of agricultural enterprises and the saw-mill industry can be used beneficially to produce crops and amend the soil for sustainable crop production. The main objective of this work was to grow Okra (Abelmoschus esculentum), an important vegetable crop in Nigeria, on soils to which these organic manures have been applied to evaluate their potential as plant nutrient sources for crop production. 2. Materials and Methods 2.1 Organic manures Organic manures used for the study were: (1) Wood ash: Collected from four saw-mills around Ilorin town. (2) Saw dust: Collected from the same saw-mills as above. (3) Pullets droppings: Pure droppings of layers, without beddings of wood shavings. (4) Pullets bedding of wood shavings: Bedding of wood shavings on which laying birds are kept in deep litter system of poultry management. (5) Broilers bedding of wood shavings: Same as (4) above, but from broiler birds. (6) Cow dung: Collected from cows paddock at the University of Ilorin Teaching and Research Farm, Ilorin. (7) Inorganic fertilizer NPK (80 kgn/ha) was also used in order to compare the performance of okra on all the organic manures and inorganic fertilizer. 2.2 Manure application, crop establishment, soil and manure analyses Each of the manure types described above was applied at 0, 4 and 8 tonnes per hectare and inorganic NPK at 80 kg/ha to designated plastic pots containing 15kg of top-soil were arranged in a Randomized Complete Block Design. The treatments were applied to and mixed thoroughly with the soils in the pots. Okra (Variety NHAe-47-4) obtained from the National Institute for Horticultural Research (NIHORT) was planted in each pot. Two stands per pot were maintained for the study. The NPK fertilizer treatment was applied two weeks after planting to the okra plants. The experiment was wetted thoroughly on the first day, then every other day till the end. Data collected include: plant height, number of leaves, fruit length, fruit diameter and fresh fruit weight and were subjected to Analysis of Variance. Significant means were separated using Least Significant Difference (LSD). All the manures were analysed for their ph (1:2 manure: water suspension) with a digital electronic ph meter; nitrogen by the regular Machro-Kjeldahl method, available phosphorus by the Murphy and Riley (1962) method after extraction with Bray s P 1 solution (Bray and Kurtz, 1945); and potassium by the flame photometric method. The topsoil used was also analysed for its native nutrient contents by the standard soil characterization methods. Total nitrogen by the regular Machro-Kjeldahl method; particle size by the Bouyoucos (1962) hydrometer method; ph in 1:2 (soil: water ratio); available P by the Murphy and Riley after extracting with Bray s P 1 solution; organic matter was deduced by first determining the organic carbon using the chromic wet oxidation method (Nelson and Sommers, 1992), then multiplying the result by a factor of Exchangeable bases- Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K) and exchange acidity were determined by extracting the soil with Normal, Neutral Ammonium Acetate solution. The Na and K in the extract were analysed by flame photometry while Ca and Mg were determined by the versenate titration method (Jackson, 1958). Total acidity was determined by extracting the soil with 1 M KCl, then titrating with 0.1M NaOH using phenolphthalein indicator. Exchangable cation 380

3 exchange capacity (ECEC) was obtained by summing up the exchangeable bases and total acidity. 3. Results and Discussion 3.1 Soil properties The native nutrients of the topsoil used for the study are as shown in Table 1. The soil is a loamy sand, having very little organic matter and total Nitrogen (N), neutral in water (ph 7.0) and generally low in basic cations and cation exchange capacity. The available phosphorus (P) was also low. These values are characteristic of the savannah soils of Nigeria (Lombin, 1983). Nitrogen has been identified as the most limiting plant nutrient element in the Nigerian savannah, followed closely by phosphorus (Ogunwale, 2003; Lombin, 1983). 3.2 NPK content of manures The N, P, and K contents of the animal manures and saw-mill wastes are as shown on Table 2. Wood ash contained the least N (7.9%), followed by pullets Litter (8.8%) and saw dust (10.7%). These levels are lower than or just about the critical 10% N required for arable crop production in these soils (Lombin, 1983; Adeoye and Agboola, 1985). Therefore, adding these materials to the soil should improve the soil N status. All the other manures contained more than enough N for arable crop production, with broilers bedding having the highest N content of 67.4% (Table2). All the manures contain adequate quantities of phosphorus and potassium for good crop production on the soil used for this study. Adding them to the soil as sources of plant nutrients will boost crop production in the study area. Nitrogen is particularly high in the broilers litter (67.4%). This may be due to the feeds fed to them, which are known to be formulated from high-protein ingredients like soybean and fishmeal. Wood ash is alkaline, having the highest ph of 9.7. This makes it a good lime material and what it lacks in N it makes up for in P and K. The ph of all the organic materials fall within the range where most plant nutrients are available to plants (Thompson and Troeh, 1975; Brady and Weil, 1999). Most of the manures contained more N and P than fertilizer NPK. This implies that their potential to supply these nutrients when applied to the soil (if inorganic fertilizer is unavailable or unaffordable) is very high. 3.3 Okra performance Results of the effects of the different types and quantity of manure and saw-mill wastes on the growth and yield of Okra are as shown in Table 3. There were no significant differences in okra height, number of leaves and fruit diameter with respect to the levels of organic material applied to the soil. However, there were significant (P<0.05) differences in the crop response to the different types of organic materials. The plant height was highest when cow dung was applied (24.3 cm), while wood ash resulted in the shortest plants (19.3 cm). All the poultry manure types resulted in plants having similar heights that ranged from 21.7 cm to 22.8 cm. This was similar to the height of plants to which inorganic fertilizer was applied. Okra fresh fruit weight increased with increasing levels of manure, though there was no significant difference in the fruit diameter (Table 3). This may be due to the fact that fruit length and diameter are genetic traits and do not vary significantly with soil nutrient supplies. Application of manure resulted in significant (P<0.05) increase in okra fresh fruit yield, 381

4 higher than the yield obtained when fertilizer NPK was applied. Broilers bedding gave the highest yield of 20.7 g/pot (2.760 t/ha.) 4. Conclusion The results obtained from this study have shown that okra producers can grow good crops without using inorganic fertilizer on this Alfisol. All they need to do is take advantage of the abundant waste products of the saw-mill industry and the poultry wastes which are abundant in this area. These organic materials which are presently being wasted, can be converted to wealth by using them as organic fertilizers. References Adeleye, E.O., Ayeni, L.S. and S.O. Ojeniyi Effect of Poultry Manure on Soil Physico-chemical Properties, Leaf Nutrient Contents and Yield of Yam (Dioscorea rotundata) on Alfisol in Southwestern Nigeria. Journal of American Science 6 (10): Adeoye, G.O. and A.A. Agboola Critical levels for soil ph, available P, K, Zn and Mn and maize earleaf content of P, Cu and Mn on sedimentary soils of south-western Nigeria. Fertilizer Research 6(1): Bouyoucos, G.J Hydrometer method improved for making particle size analysis of soils. Agronomy Journal. 54: Brady, N.C. and R.R. Weil The nature and properties of soils. 12 th edition, Simon and Schuster Co., Prentice Hall Inc. New Jersey. Bray, R.H. and L.T. Kurtz Determination of Total, Organic and available forms of P in soils. Soil Science. 59:39-45 Fawole, O.B.; T. J. Ajayi, M.O. Aduloju and J. O. Olaniyan The use of Parkia husk and melon wastes as soil amendment. Journal of Agric. Research and Development, University of Ilorin. In Press. Jackson, M.L Soil chemical analysis. Prentice-Hall Inc. Englewood Cliffs. New Jersey, U.S.A. Lombin, G Evaluating the micronutrient status of Nigeria s semi-arid savanna soils. 1.Copper and Manganese. Soil Science 135(6): Murphy, J. and Riley, J.P A modified single solution method for the determination of phosphorus in natural waters. Analytical Chimica Acta. 27:31-36 Nelson, D.W. and Sommers, L.E Total carbon, organic carbon and organic matter. Pp , In Methods of Soil Analysis. Part 2. Second Ed. Page, A.L. et al. Agronomy Monograph 9. ASA and SSSA, Madison, WI. Ogunwale, J. A Soil phosphorus and phosphate fixation. Third in the series of Faculty of Agriculture Seminars, University of Ilorin, Nigeria. pp 20. Senjobi, B. A., C. O. Peluola, C. T. Senjobi, I. O. Lawal, O.T. Ande and B. T. Salami Performance of Cochorus olitorius as influenced by soil type and organic manure amendments in Yewa North Local Government Area, Ogun State. African Journal of Biotechnology 9(33): Thompson, L.M. and F. R. Troeh, F.R.(1975). Soils and Soil Fertility. Tata McGraw-Hill Publishing Company Ltd., New Delhi. 382

5 Table 1: General characteristics of the Alfisol used Characteristics Values Sand (%) 74 Silt (%) 13 Clay (%) 13 Texture Loamy sand ph in H 2 O 7.0 Available P (mg/kg soil) 9.73 Organic matter (mg/kg soil) 0.86 Total N (%) 4.9 Exchangeable Ca ( Cmol c /kg soil) 0.7 K 0.1 Na 0.17 acidity 0.15 ECEC 1.46 Table 2: Nitrogen, Phosphorus and Potassium contents and ph of the manures used Manures ph Total N P K In H 2 O Cmol/kg soil mg/kg soil Cmol/kgsoil Wood Ash Saw Dust Pullets Droppings Pullets Litter Broilers Litter Cow Dung

6 Table 3: Effect of types and levels of organic manure and fertilizer NPK on growth and yield of Okra. Manure types Plant Number Fruit Fruit Fresh and levels height of leaves diameter length fruit (cm) (cm) (cm) weight (g/pot) Wood Ash a 5.7ab 13.4ab Saw Dust 22.2ab 9 2.5a 6.9ab 19.3ab Pullets Droppings 22.4ab 9 2.2ab 6.1ab 13.9ab Pullets Litter 21.7ab b 4.3b 10.1b Broilers Litter 22.8ab a 8.0a 20.7a Cow Dung 24.3a 9 2.2ab 7.1ab 14.6ab Fertilizer NPK 21.2ab b 5.8ab 12.8ab SED 4.02 NS tonnes/ha b 6.3c 4 tonnes/ha ab 12.8ab 8 tonnes/ha a 19.1a SED NS NS Means followed by the same letter(s) are not significantly different according to Duncan z Multiple range test (DMRT) at p<