Influence of Spacing on Growth and Yield of Blackgram Varieties

The productivity of blackgram (Vigna mungo L.), a vital pulse crop in South Asia, remains suboptimal in Bangladesh due to improper agronomic practices, particularly inadequate plant spacing. This study was conducted at the Agronomy Field Laboratory of Sher-e-Bangla Agricultural University, Dhaka, during the kharif season of 2015 to assess the influence of different spacing regimes on the growth and yield performance of three blackgram varieties—Munshigonj Local, BARI Mash-2, and BARI Mash-3—under the System of Crop Intensification (SCI). A split-plot design was employed with five spacing treatments (30×10 cm, 20×20 cm, 30×30 cm, 40×40 cm, and 50×50 cm). The results showed significant variation in plant height, aboveground biomass, crop growth rate, pods per plant, 1000-seed weight, and grain yield. Closer spacing (30×10 cm) enhanced vertical growth but reduced seed yield due to high competition, while wider spacing (50×50 cm) improved individual plant biomass but reduced yield per unit area. Moderate spacings (20×20 cm and 30×30 cm) provided a balance between growth and yield parameters, with BARI Mash-2 at 30×30 cm yielding the highest (1.82 t ha⁻¹). These findings suggest that optimized variety-specific spacing under SCI can significantly improve blackgram productivity in subtropical regions of Bangladesh.