Effect of sowing dates and spacing on growth and yield of cluster bean (Cyamopsis tetragonoloba) in subtropical climate of Assam, India

A field experiment was conducted during the year 2009 to 2011 in rainy season to find out the optimum time of sowing and plant spacing of cluster bean (var. Pusa Naubahar) in Assam. Four sowing time viz. 1^st July, 15^th July, 1^st August and 15^th August and three spacing plant spacing i.e. 45 x 30 cm,60 x 30 cm and 45 x 45cm were evaluated. The experiment was laid out in split plot design with three replications. The obtained results showed that all characters were markedly affected by sowing dates and spacing. Most of the characters studied except flowering date, decreased by delaying sowing date from Ist Jul to 15^th Aug. Increasing spacing from 30 to 60 cm significantly increased pods/plant and leaf area, but decreased maturity date and plant height. The % disease infestation of collar rot was found minimum with earlier sowing plants. The interaction effect of (S x D) was significant for plant height, pods/plant and leaves/plant. Sowing the crop on 1^st July at a spacing of 45 x 30 cm produced the highest pod yield (12.46 t/ha) and the lowest pod yield 7.12 t/ha was recorded in Aug 15^th sowing with 45x45 cm spacing. Results of the present study revealed that 1^st July sowing and 45 x 30 cm spacing was suitable for cluster bean production under agro climatic condition of Assam. Evaluation of production economics revealed 1^st July sowing with 45 x 30 cm plants was also most remunerative option with a highest benefit: cost ratio of 2.83.