Abstract
The experiments were carried out at the Bangladesh Sugarcane Research Institute farm, Ishurdi, Pabna, Bangladesh in 2008-2009 and repeated in 2009- 2010 and 2010-2011 cropping seasons to investigate the effects of light interception on successive intercropping in sugarcane for profitable cultivation. The present experiment comprises six pair of intercrops for successive intercropping in sugarcane. These are potato-mungbean, lentil-mungbean, chickpea-mungbean, potato-sesame, lentil- sesame and chickpea- sesame. As treatments, three row to row spacing of sugarcane such as 80 cm, 100 cm and 120 cm were maintained and intercropped with 1, 2 and 3 rows of intercrops, respectively cultivated following recommended cultivation methods of respective crops. To provide more light to intercrops leaves of sugarcane bended to both side of row were cut at bending and compared to non-cutting of leaves. Data on sugarcane plant height, number of tiller, LAI, TDM, stalk height, stalk diameter, sugarcane yield, Brix %, pol % cane, purity %, recovery % and sugar yield were also recorded. Similarly data on plant height, LAI, TDM, tuber number and yield of intercrops were also recorded. The parameters differed in respect to different successive intercropping. The highest LAI, TDM, cane yield and sugar yield were observed at row to row spacing (RRS) of 100 cm with 3 rows of potato followed by 3 rows of mungbean (S2Co) under non leaf cutting (NLC). The number of tiller and millable cane were highest at RRS 80 cm of sugarcane + 1 R potato-1 R mungbean with NLC (S1Co). Brix (%), pol (%) cane, purity (%) and recovery (%) were insignificant in all experiments. The effects of light transmission and light interception were insignificant for growth and yield of 1st intercrop but significant for 2nd one. For the growth and yield of mungbean (2nd intercrop), light interception (%) was significantly lowest in SзC1 where sugarcane RRS was 120 cm + 3 R potato-3 R mungbean with leaf cutting (LC). The highest adjusted cane yield (170.66 t ha-1), benefit cost ratio (3.49) and LER (2.33) were observed in sugarcane at RRS 120 cm + 3 R potato followed by 3 R of mungbean with LC of sugarcane (S3C1). The results of the experiment indicated that sugarcane transplanted at RRS at 120 cm with three rows potato followed by 3 rows of mungbean can be grown as intercrops for higher economic return. Final evaluations confirmed that the most suitable variety of sugarcane was Isd 37 for successive intercropping of potato-mungbean. The highest adjusted cane yield (141.08 t ha-1), BCR (4.06) and LER (2.24) were observed in sugarcane Isd 37, at RRS 120 cm + 3 R potato - 3 R mungbean with LC. Therefore, it may be concluded that sugarcane Isd 37 transplanted at RRS 120 cm under leaf cutting with 3 rows of potato and mungbean as first and second intercrops, respectively might be recommended for High Ganges River Flood Plain soils under AEZ 11 of Bangladesh.