Ecological aspects study of replacement intercropping patterns of Soybean (Glycine max L.) and Millet (Panicum miliaceum L.)

Intercropping is considered for increasing and stability of yield in per unit. In order to study the effects of soybean (Glycine max L.) and millet (Panicum miliaceum L.) replacement intercropping on agronomic traits, diversity of weeds and soil biological activity, an experiment was conducted at the Research Station of Agricultural Faculty, of Bu-Ali Sina University, in 2014. The experiment was carried out as a randomized complete block design with three replications. The replacement intercropping series consisted of monoculture of soybean, monoculture of millet, 75% soybean 25% millet, 50% soybean 50% millet and 25% soybean 75% millet. The results showed that the highest seed yield of 219.8 and 171.9 gm-2 belonged to monoculture of soybean and monoculture of millet, respectively. Intercropping reduced maximum leaf area index of soybean and millet but leaf chlorophyll content of soybean and millet were increased. The highest number of pods per plant, number of seeds per plant in soybean and panicle number per plant in millet were obtained in 50S:50M ratio. Mean soil respiration rate in intercropping treatments was 4 and 8 % higher than the monoculture of soybean and millet, respectively. Intercropping patterns of 50S:50M and 25S:75M were successful in reducing weed plant density and diversity in comparison with soybean monoculture. Results showed that in all intercropping treatments, land equivalent ratio was more than one. Maximum value of land equivalent ratio (2.20) was achieved in 50S:50M treatment. Soybean and millet intercropping at different levels of replacement, didn’t have actual yield loss. Calculating the aggressivity showed that millet was more dominate than soybean. The maximum relative crowding coefficient of soybean was observed in 75S:25M, however that of millet was obtained in 25S:75M and 50S:50M intercroppings indicating that millet is more competitor than soybean.