Radiation interception and growth in an intercrop of pearl millet/groundnut uri icon

abstract

  • Quantum flux measurements of the transmission of photosynthetically active radiation (PAR) are presented for the monocrops and an intercrop of 82-day-old pearl millet cv. BK 560 and 105-day-old groundnut cv. Robut 33-1. The intercrop row arrangement was 1 millet : 3 groundnut and intrarow spacing of each spp. was the same in monocrop and intercrop. The results for PAR were compared with similar measurements of total solar radiation. There was a linear relation between the log. of the transmission coeff. in the 2 wavebands and this was independent of both age and structure of the canopies and was used to convert measurements of total solar radiation into quantities of PAR intercepted by the crops. Dry wt. of monocropped millet increased linearly with intercepted PAR during the vegetative and much of the reproductive phases but dry wt. of monocropped groundnut only increased linearly in the vegetative phase. During early pod filling there was no increase in dry wt. despite a substantial quantity of PAR interception; later, dry wt. of the groundnut increased by a further 30%. Similar relations were observed for the 2 components of the intercrop. Intercropping gave 28% more total DM (Land Equivalent Ratio = 1.28) than growing the 2 crops separately. Millet intercepted 2.1 times more PAR in the intercrop row than in the monocrop row and used it with a similar efficiency to produce twice as much DM. Intercropped groundnuts intercepted 27% less PAR/row than in the monocrop but used it with 46% greater efficiency to yield the same

publication date

  • 1983
  • 1983