Effect of plant densities and phosphorus levels on the growth and yield of vegetable cowpea (Vigna unguiculata L.) var. Arka Garima K. RAVI KUMAR1 AND V. SUDHA VANI2
Department of Horticulture, College of Horticulture, Venkataramannagudem-534 101, Andhra Pradesh, India. E-mail : email@example.com
A field experiment was conducted at College of Horticulture, Venkataramannagudem to study the effect of plant density and phosphorus levels on the growth and yield of vegetable cowpea variety Arka Garima under irrigated conditions. The study revealed that the crop responded to plant densities as well as phosphorus levels. The biometric characters like number of primary branches per plant (8.52), pod length (21.31 cm), pod girth (12.35 mm), number of pods per plant (37.02), number of seeds per pod (16.85), pod weight per plant (10.93 g) and pod yield per plant (301.85 g) were higher at lower density plants (37,037 plants/ha) along with 60 kg P2O5/ha. The growth and yield characters like plant height (52.47 cm), TDM accumulation (3968.04 kg/ha), days to flowering (34.73 days), days to first picking (44.28 days) and pod yield (152.87 q//ha) were showed better expression in case of high density planting (74,074 plants/ha) along with 60 kg P2O5/ha. The interaction effect of plant densities and phosphorus levels were significant on plant height, total dry matter accumulation and days to flowering, pod length, pod weight per plant, and yield per plant and pod yield /ha. Key words: Growth, yield, plant density, phosphorus level, vegetable cowpea Cowpea plays a substantial role by serving as a grain and vegetable crop mainly for the rural people in the East, West, South and Central parts of Africa (Mortimore et al., 1997). According to FAO (2007), cowpea is produced annually on 11.2 mha ranking 3rd after common bean (Phaseolus vulgaris L.) and chickpea (Cicer arietinum L.) with Africa taking the lead followed by Asia. It is extensively grown in South India particularly in the states of Karnataka and Tamilnadu. Cowpea used at all stages of its growth including as a vegetable (Ofori and Stern, 1986). Vegetable cowpea variety Arka Garima is a bushy type. Pods are thick, light green, long, round, stringless and highly fleshy. Yield potential of Arka Garima is 18 t/ha. The optimum plant population is an important parameter for increasing the crop productivity and provides the plant with the best environment to express its capacity fully under the given conditions. The optimum plant density with proper geometry and its planting varied with the agro-climatic conditions and growth habit of the plant. Generally, pulses require phosphorus for their growth and nitrogen fixation. It also enhances the nodulation and pod development consequently pod yield. If the phosphate availability from the soil is limited, the growth and nitrogen fixation are affected (Prasad and Sanoria, 1981). Phosphorus being an essential constituent of cellular proteins and nucleic acids, it encourages the meristematic activity in plants (Black, 1969) and adequate supply of nutrients which might have enhanced the metabolic activity and inturn plant growth.
MATERIAL AND METHODS
A field experiment was conducted at College of Horticulture, Venkataramannagudem during kharif 2010. The experimental site had red sandy loam with pH 6.9, EC of 0.01 dS/m, 0.34 % organic carbon with 712, 32.5, 217.5 kg of N, P2O5 and K2O per ha, respectively. The experiment was laid out in factorial randomized block design with three replications. There were twelve treatmental combinations comprised of three plant densities (37,037, 55,555 and 74,074 plants/ha) designated as D1, D2 and D3 and four levels of phosphorus (0, 20, 40 and 60 kg P2O5/ha) designated as P0, P1, P2 and P3. The seeds were treated with captan @ 3g/kg seeds before sowing against wilt. The Arka Garima seeds were dibbled on 29-8-2010 at 60 x 45, 60 x 30 and 45 x 30 cm spacings. During the crop period, the total...
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