Evaluation of Competition and Complementarity of Corn (Zea mays) and Cowpea (Vigna sinensis) Intercropping for Nutrient Consumption

If the intercropping components have a complementarit y effect in consuming environmental resources, the crop production will be more in intercropping compared to sole crops. A field experiment was carried out in during 2003 to investigate the competition and complementarity between intercropped components of corn and cowpea in nutrient uptake. A randomized complete block design (RCBD) was employed to compare the treatments including cowpea sole crop (Cp), corn sole crop (C), within-row intercropping (M1), alternate intercropping (M2) and mixed intercropping (M3). Intercropping was conducted as replacement method, where one corn plant was replaced by three cowpea plants. The results indicated that nutrient uptake by intercropping was more than sole crop which should be noticified for nutrient supply of the next crops. Cowpea was more competitive than corn in absorbing divalent cations (Ca and Mg) for its high root cation exchange capacity. However, corn was more competitive for phosphorus and potassium which is related to its expanded root system. For all intercrops, relative yield total (RYT) was significantly higher than unity, indicating that corn and cowpea were complement for nutrient consumption. This shows the advantage of intercropping in consuming an effective environmental resource for production, compared to sole crops.