Evaluating performance of corn (Zea mays L.) / soybean [Glycine max ) L.) Merr] intercrop in different planting dates

Intercropping is considered for increasing and stability of yield in per unit. In order to evaluating the effect of corn/soybean intercrop in different planting dates, a study was carried out in Agricultural Sciences and Natural Resources, University of Sari, Faculty of Agriculture during 2005-2006. The experiment was a split plot design based on randomized complete block design with four replications in two years. The main plots were planting dates (A) at three levels; April 20 (a1), May 4 (a2) and May 19 (a3). Sub plots assigned to planting seed density at five levels: 8 rows of corn as control (b1), 2 soybean + 2corn rows (b2), 3 corn + 2 soybean + 3 corn rows (b3), 3 corn + 2 soybean +3 corn rows (b4) and 8 rows of soybean as control (b5). Results showed that the highest yield, seed numbers in m2, seed numbers per plant, seed numbers per ear and ear dry weight in corn, were obtained on may 19 in second year. Soybean yields were reduced significantly when intercropped with maize in both years. Yield, seed numbers per plant and per square meter in corn increased while in soybean decreased significantly as the number of rows of corn increased. The most Land Equivalent Ratio (LER), 1.37 was obtained in intercropping and b3 treatment. By increasing the rows of corn and decreasing that of soybean, LER was increased. Furthermore the results showed a beneficiary of corn /soybean intercrop.