A field experiment was carried out at the Teaching and Research Farm of the Faculty of Agriculture, University of Benin, Benin City to investigate the effect of different levels of poultry manure on the growth and yield of two varieties of tomatoes. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The treatment composed of four levels of poultry manure (0, 5, 10 and 15 tha-1) and two varieties of tomato (UC82-B and Roma VF). Each replicate had 8 plots for a total of 24 plots. The parameters measured were plant height, leaf area, number of leaves, number of branches, days to first flowering, days to 50% flowering, number of flowers, number of fruit, fruit diameter, fruit length, fruit fresh weight, fruit dry weight, shoot fresh weight and shoot dry weight. The result of this study indicated that poultry manure significantly affected all the parameters measured except plant height. All the parameter measured were increased in Roma VF than in UC82-B except the number of flowers, days to first flowering, fruit length, fruit diameter, shoot fresh weight, fruit dry weight and shoot dry weight where the two varieties were similar. Application of 5 and 10 tha-1 poultry manure were similar and significantly increased fruit fresh weight above the control and 15 tha-1. However, the highest yield was obtained from 5 tha-1 poultry manure with either Roman VF or UC82B which were significantly at par.
The tomatoes (Lycopersicon esculentum) belong to the family of solanaceae. It is one of the most important vegetable in Nigeria and in many parts of the tropical and sub-tropical regions of the world. According to Hussaini et al., (2000) the crop rank first in importance among vegetables in Nigeria. It is grown mainly for its fruits, which is used almost daily in every home.
Tomato is an annual herbaceous plant which takes about 75 – 85 days to attain maturity. The plant may reach a height of 2m depending on the variety. The leaves are large, greenish, deeply cleft, with many leaflets. The leaves are arranged alternatively along the stems. The flowers are pinkish to yellow in contour, borne in clusters of four to six flowers sometimes more, formed on the stems between the leaves. Tomatoes fruits exist in many shapes appearing large and round, oval or elongated, depending on the variety. The fruits may be orange, yellow or red when ripe, usually with numerous kidney or peer shaped, hairy, light brown seeds (Tindall, 1993).
Tomato is a warm season plant that requires temperature of about 20-270c for most cultivars. Excessive rainfall and high relative humidity can be harmful to it. A deep loamy soil well drained rich in organic material with a pH of 6.2 – 6.8 for optimum growth and development. It is a nutritious vegetable with increasing demand in Nigeria. As documented by United States Dietary Allowance (2008) tomato fruit provide 95% water of its edible portion and the remaining 5% compose of miscellaneous compound among which include carotenoids, ascorbic acids, alcohol, insoluble solids (proteins) cellulose, pectins, polysaccharides and inorganic compound which give the fruit its characteristic flavor and aroma. In addition, Micheal (2006) revealed that tomatoes are among the food plants to which moderate level of anti cancer activities is associated. It also contains Vitamin A which is a remedy for night blindness.
Tomato originated in South America, but its cultivation has today spread to nearly all parts of the world. But however, it was introduced to West Africa by the Portuguese in the 16th century. The world’s cultivation of tomato is put to about 4 million hectares of which 63,482 hectares are estimated to be cultivated. In Nigeria, FAO (2010) reported an estimated annual production of 1.7 million tones. But however, this was still far below demand as there was an increasing demand from human consumption.
However, most of the deficits were offset by importation. Although, despite a drive towards increased tomatoes production in Nigeria, an optimum production has not been realized by the framers to meet its demand among consumers.
Generally, tomato production in Nigeria has been low because of low yields obtained by small scale farmers resulting from the use of unimproved local varieties with low yielding capacity which often grown in mixtures and this may prevent exploitation of crop productive capacity, environmental hazards such as drought and incidence of pest and diseases, plant population including soil fertility decline and a host of other factors have also kept tomato yield output relatively low (Adekiya and Ojeniyi, 2002).
The use of inorganic fertilizers alone has not been helpful under intensive Agriculture because it aggregates soil degradation (Sharma and Mittra, 1991). The degradation is brought about by loss of organic matter which consequently results in soil acidity and low crop yields (Ojeniyi, 2000). The quantity of soil organic matter depends on the quality of organic material which can be introduced into the soil either by natural returns through roots, stubbles, sloughed-off root nodules and root exudates or by artificial application in the form of organic fertilizer such as poultry manures. (Agboola and Omueti, 1982). Poultry manure is an important means of maintaining soil fertility status. It is cheap, readily available and more environmentally friendly. Nutrients contained in organic manures are released more slowly and are retained for a longer time in the soil, thereby ensuring long residual effect (Sharma and Mittra, 1991). Inorganic fertilizer on the other hand have high concentration of nutrients and readily available to crops but its use is hampered by its inaccessibility to majority of the farmers due to high cost in developing countries including Nigeria (Webber et al., 1999).
The application of poultry manure was reported Ewulo et al., (2008) to significantly affect tomato plant height, number of branches, root length, number and weight of fruits of tomatoes.
In recognition of the increasing economic importance of tomatoes, intensifying production through the use of improved varieties and organic manure has become imperative.
Most of the varieties available to farmers are local and low yielding, generally sown in mixture with other vegetables or cereals. Therefore, the performance and yield potentials of high yielding varieties such as Roma VF and UC 82B released by NIHORT need to be evaluated to replace the low yielding local varieties currently in use by farmers.
The present study was conducted to determine the optimum poultry manure rate for these two varieties of tomatoes in rainforest zone of Nigeria.