A field experiment was conducted at the Agronomy farm, Eastern University, Sri Lanka to study the biological
and economic efficiency of radish (Raphanus sativus L.) intercropped with vegetable amaranthus (Amaranthus tricolor
L.). Treatments were radish as sole crop (T1), vegetable amaranthus as sole crop (T2), 20/50 cm paired row radish
with three (T3) or four (T4) rows of vegetable amaranthus in between paired rows and 25/40 cm paired row
radish with three (T5) or two (T6) rows of vegetable amaranthus in between paired rows. The results showed
that, there was no significant difference (P>0.05) in area time equivalency ratio (ATER) among intercropping treatments
and significant differences (P<0.05) were obtained in the land equivalent ratio (LER) and crop performance ratio (CPR).
LER (1.31) and CPR (1.71) were superior in T3 and T4 respectively. In case of economic indices, gross return was significantly
differed (P<0.01) among treatments. It was high in T3 followed by T4. Intercropping system recorded significantly
high (P<0.01) cost of cultivation over intercropping system. Among intercropping, T4 resulted maximum net return,
monetary equivalent ratio, cost benefit ratio and per day return over other intercropping treatments and sole crops.
This experiment revealed that T4 would be the most efficient system in both biological and economical point of view.