Agronomic and physiological response of tobacco (Nicotiana tabacum L.) intercropped with some annual upland crops at two spatial arrangement [Philippines]

At 49 and 63 DAT, the height of tobacco plants intercropped with corn were significantly taller than the monoculture because the growth of tobacco was enhanced by the shading effect of corn. On the contrary, the corn intercrop reduced the number of harvested leaves plant-1 and the quality of tobacco leaves produced. Spatial arrangement and intercrops also significantly reduced the yield and dry matter ha-1 and crop value index (CVI) of tobacco. Spatial arrangement and intercrops did not affect the nicotine content of tobacco leaves but corn intercrop significantly lowered the reducing sugar and reducing sugar: nicotine ratio of tobacco. For the intercrops, vine length of sweet potato at 77 and 91DAP were significantly longer than the monoculture. The yield plant-1 and per hectare of sweet potato was also reduced when intercropped with tobacco while the yield plant-1 and per hectare of peanut was reduced only when intercropped in the double row arrangement. Spatial arrangement also affected the relative leaf growth rate (RLGR) and crop growth rate (CGR) of tobacco. Relative leaf growth rate was higher in the single row arrangement at 30-45 DAT while the CGR of tobacco was higher in the double row than in the single row arrangement at 30-45 and 75-90 DAT. All the tobacco with intercrops had lower CGR and leaf area index (LAI). The tobacco intercropped with corn had the lowest RLGR and CGR at later growth stages. On the other hand, the RLGR of the intercrops was not affected by intercropping except for mungbean at 45-60 DAP. Intercropping also reduced the CGR of corn but not sweet potato, peanut and mungbean. Likewise, the LAI of corn, sweet potato, peanut and mungbean was decreased when intercropped with tobacco. Only the harvest index of peanut intercropped in the double row was reduced by intercropping. At 30-60 DAT, only the tobacco plus corn had higher combined CGR than the monoculture tobacco. Combined LAI in all of the crop combinations was significantly higher than the monoculture tobacco at 45 DAT. Light interception was higher in the intercropping system than the monoculture tobacco at 45-60 DAT and 60-75 DAT