Response of Cowpea (Vigna unguiculata) to Spacing in the Savanna and Rainforest Zones of Nigeria

Abstract

S U M M A R YA two year field study designed to investigate the effect of spacing on yield of two cowpea cultivars in the savanna and forest zones of Nigeria showed that cowpea yields were larger in the savanna than in the forest zone at all spacings employed. Inter-row spacing wider than 60 cm and intra-row spacing closer than 10 cm could be used for improved seed yield in the savanna zone, while 60 x 20 cm (83 333 plants ha~') would be optimum for cowpea production in the forest zone.Spacing is an important factor affecting the yield of cowpea. In Nigeria, cowpeas are grown sole or mixed with other crops at very irregular spacings. For successful production of this crop, knowledge of optimum inter-row and intrarow spacing is required. Few such reports are available (Remison, 1980;Nangju et al., 1975;Ezedinma, 1974). A small plant population (wide spacing) can lead to a significant reduction in yield of cowpeas (Ezedinma, 1974) and Enyi (1973) showed that yields increase with increasing plant density. Kayode (1984) reported a non-significant response to spacing by yam (Dioscorea rotundata) in the savanna zone, whereas yield increased with spacing in the forest zone. Willey and Heath (1961) stated that the yield of plants depends not only on plant density (plants per unit area) but also on the spatial arrangement of these plants (plant rectangularity), i.e. the ratio of the distance between plants within the row to the distance between the rows. This paper reports on the response of cowpea to spacing and plant rectangularity in the savanna and rainforest zones of Nigeria. MATERIALS AND METHODSA field experiment was carried out in the early growing seasons of 1980 and 1981 at Ibadan (7° 25' N, 3° 52' E) in the rainforest zone and at Mokwa (9°1 8' N, 5° 4' E) in the southern guinea savanna zone of Nigeria. Two indeterminate cowpea cultivars, Ife Brown and New Era, were sown at four inter-row spacings (30, 40, 50 and 60 cm) and five intra-row spacings (10, 15, 20, 25 and 0014-4797/85/0000-0974 $05.00© 1985 Cambridge University Press

Response of Cowpea (Vigna Unguiculata) to Spacing in the Savanna and Rainforest Zones of Nigeria: Response Surface Analysis

“…Within the range examined by this experiment, therefore, a spacing of 60 X 9 cm could be recommended for cowpea production in the savanna. This gives a plant population of 185 000 plants ha" 1 and agrees with results obtained previously by Kayode and Odulaja (1985). If practicable, a closer intra-row spacing may be used.…”

“…Two indeterminate cowpea cultivars, Ife Brown and New Era, were sown at four inter-row and five intra-row spacings in randomized complete blocks of 40 plots with three replications. Details of the experiment are given by Kayode and Odulaja (1985).…”

“…Berry (1967) described a model relating the yield of plants, regularly spaced, to the inter-row and intra-row spacings, and showed that the model had reasonable properties at extremes while giving a satisfactory fit to a published set of experimental data. Berry's model will here be used to throw more light on the response of cowpea to spacing in the savanna and rainforest zones of Nigeria, using experimental data already presented by Kayode and Odulaja (1985).…”

Effect of spacing in cow pea (Vigna unguiculata) on damage by the black cowpea moth, Cydia ptychora (Lepidoptera: Tortricidae)

“…Wide spacing can lead to a significant reduction in yield (Ezedinma, 1974). Similarly, a high plant population (close spacing) may depress yield (Remison, 1980) or have no yield advantage (Kayode & Odulaja, 1985). Whatever the density is at which yield is optimised, it is clearly disadvantageous to increase density still further as this is likely to lead to even greater damage by the black cowpea moth.…”

Produtividade e morfologia de genótipos de caupi em diferentes densidades populacionais nos sistemas irrigado e de sequeiro

“…Para Crothers & Westermann (1976), o emprego de tecnologia, a necessidade de maior flexibilidade nos métodos de colheita e o desenvolvimento de genótipos de porte semi-ereto aumentam o interesse para a definição de níveis ótimos de plantas por unidade de área. Uma pequena população de plantas pode conduzir a uma significativa redução na produtividade do caupi, e trabalhos têm demonstrado que o rendimento aumenta com o aumento da população de plantas (Kayode & Odulaja, 1985). Jallow & Ferguson (1985), estudando o comportamento de 18 genótipos de diferentes hábitos de crescimento, em Trinidade, observaram que os melhores níveis populacionais oscilaram entre 40.000 e 250.000 plantas/ha.…”