Response of Cowpea (Vigna unguiculata L. Walp) to Time of Application and Nitrogen Fertilizer on the Degraded Soil of Southern Guinea Savanna Zone of Nigeria

Abstract

Field trials were conducted during 2017 and 2018 rainy season, to investigate the effect of nitrogen fertilizer rates and time of application on the growth and yield of cowpea. The treatment consisted of three levels of urea: 0, 40, 80 kg N ha-1 and the times of fertilizer application: during planting of cowpea, 2 weeks after planting, 4 weeks after planting and 6 weeks after planting; which were factorially combined to form twelve treatments and laid in Randomized Complete Block Design (RCBD). The results showed that, Nitrogen fertilizer rates and time of application had a significant increased on all the growth and yield parameters of cowpea in both years of trials. Application of 80 kg N ha-1 produced the highest number of cowpea leaves (134.45 and 139.23), number of branches (9.45 and 10.54), vine length (78.23cm and 80.12cm) and highest seed weight of 0.52 t ha-1 in both 2017 and 2018 trials. However, the control plots produced plants with the highest number of root nodules (14.78 and 12.49) in both years of cropping. Also, application of nitrogen fertilizer at two weeks after planting of cowpea produced the highest growth and seed weight of 0.68 t ha-1 in 2017 cropping; while in 2018 trial, application of nitrogen fertilizer at two weeks after cowpea planting produced seed yield of 0.69tha-1 which is statistically similar with application of nitrogen fertilizer on the fourth week after planting which produced 0.55 t ha-1 of cowpea seeds. The interaction between nitrogen fertilizer application rates and time of application did not showed any significant difference in cowpea yield and yield components in both years of cropping.

EFFECT OF PHOSPHOROUS RATES ON GROWTH AND YIELD OF COWPEA [Vigna unguiculata (L.) Walph.] VARIETIES IN JOS NORTH, PLATEAU STATE, NIGERIA

“…The use of P fertilizer boosted the components of yield in terms of number of pods per plant, number of seeds per pod, and total yield significantly (P0.01). Other researchers have observed a considerable increase in yield qualities of cowpea in response to P treatment, and the findings in this study are consistent with their findings (Singh et al, 2011;Ndor et al, 2012;Haruna and Usman, 2013). The findings were comparable to those of Boahene (2013), who found that phosphorus application improved the number of pods plant -1 , hundred seed weight, shelled seed yield, and dry matter yield up to a rate of 20 kg P ha -1 , but dropped after that rate of P. Highly significant (P≤0.01) varietal difference was observed in both seasons (Table 3).…”

“…However, the findings contrast those of Shiyam (2010), who found that varying phosphorus levels had no significant effect on plant height. The significant growth response of cowpea to Phosphorus fertilizer application can be attributed to the fact that Phosphorus stimulates root and plant growth, initiates nodule formation, and influences the overall efficiency of the rhizobium-legume symbiosis, thereby optimizing the Biological Nitrogen Fixation (BNF) system of legumes (Ndor et al, 2012).…”

“…Days to first flowering and days to 50% flowering of the varieties was influenced by phosphorus levels of cowpea varieties (Mawo et al, 2018). Ndor et al (2012) found a considerable variance in growth and yield characters of some improved cowpea varieties, which they attributed to the genetic makeup of the varieties studied and the available phosphorus in the soil. Similar report was made by Krasilnikoff et al (2003) and Singh et al (2003) that varieties differ in their genetic makeup and this could have reflected their yield.…”

Impact of Phosphorus Levels and Spacing on Growth, Yield and Development of Cowpea (Vigna unguiculata L. Walp.)

“…Application of phosphorus (50kg/ha) showed that maximum number of nodules/plant that increase in nodulation might be due to stimulates the root and plant growth, initiates nodule formation as well as influence the general efficiency of the rhizobium-legume symbiosis, thereby optimizes the Biological Nitrogen Fixation system of legume. Similar results have been reported by Ndor et al [14]. Further, higher number of nodules/plant was observed with spacing (30cm×30cm) might be due to wider spacing there is less competition for space, moisture and nutrient might have probably increased root nodule as compared to close spacing.…”

Modeling of Cowpea (Vigna unguiculata) Yield and Control Insecticide Exposure in a Semi-Arid Region

“…The average grain yield (475 kg/ha) and seed (452 kg/ha) were higher than the average yield of 300-400 kg/ha as reported [73]. However, these average yields were different in relation to research proposed [74,75] where average yields were of 724-844 kg/ha, and 526.5-7645.1 kg/ha. The average seed yield treated with insecticide (654.3 kg/ha) and untreated with insecticide (266.1 kg/ha) in our study was lower than the value achieved [76], reaching 60.7-1184.2 kg/ha.…”