| Intercropping advantage occurs only when each species must have adequate time and space to maximize cooperation and minimize competition between them.Two field experiments were carried out to investigate the effects of narrow-row planting patterns on crop growth, the competition ability and intercropping advantage. The results are following.1. Narrow-now planting patterns significantly affected the yield and yield component of maize and soybean in intercropping systems. Compared with sole maize, the yield of intercropped maize was decreased. With the narrow spacing increasing, the decreased amplitude of intercropped maize was decreased, and no significantly different from sole maize. Compared with sole maize, the maize yield of 20cm,30cm,40cm,50cm,60cm,80cm and equal row planting pattern was decreased by 32%,24%,15%,10%,8%,5% and 1%. The lost of maize yield comes from the reducing of kernels per ear. Compared with sole soybean, the soybean yield of 20cm,30cm,40cm,50cm,60cm,80cm and equal row planting pattern was decreased by 12%,15%,20%,24%,30%,45% and 50%. The lost of soybean yield comes from the reducing of effect number and pod number.2. Intercropping systems were assessed on the basis of several existing intercropping indices such as land equivalent ratio(LER), actual yield loss(AYL),intercropping advantage (IA), and monetary advantage index(MAI). With the increasing of maize narrow-row spacing, the trend of LER was "low-high-low". The greatest LER of intercropping were 1.61 and 1.59 for 2012 and 2013, appeared in 40:160 treatment. The highest values of AYL, IA and MAI were recorded for maize-soybean relay strip intercropping (0.4:1.6).Overall, intercropping of maize with soybean at 0.4:1.6 will give higher income, better land use efficiency and thus enhancing sustainability of production than the other mixtures.3. For intercrops in intercropping system, the values of A and CR indicated that the maize was more competitive than soybean.With the narrow-row spacing increasing, the competition strength of maize decrease while soybean competition become more intense. And the root barrier treatment has no significantly effect on the crops yield in maize-soybean relay strip intercropping systems. Moreover, the effect of shoot competition was more important than the root competition.4. Narrow-row planting patterns significantly affected the distribution of maize and soybean in intercropping systems. Similar to the yield, with the narrow spacing increasing, the dry matter accumulation of maize increased, while soybean was decreased. Moreover, with the narrow-row spacing increasing from 20cm to 100cm, the translocation efficiency and contribution rate of maize were increased from 11.0% to 20.5% and from 13.5% to 27.0%, respectively; The intercropped soybean has an opposite trend, the translocation efficiency and contribution of soybean were decreased from 28.5% to 17.5% and from 71.0% to 52.0%, respectively.5. The intercropping advantage and contribution of above-ground and below-ground interactions in maize-soybean relay strip intercropping systems were incestigated. The results showed that the land equivalent ratios (LER) of all narrow-row planting patterns were over 1.0, showing yield advantages of three planting patterns. The contribution of above-ground was more important than the below-ground interactions to nutrient advantage. Besides, the nutrient advantage mainly comes from the nutrient uptake increasing rather than nutrient use efficiency.In summary, the best intercropping of maize with soybean at 40:160; and the above-ground factor was contributed to the intercropping advantage in maize-soybean relay strip intercropping system. Therefore, the compeitition for light resource was the emphasis of future reaseach. |
PDF Full Text Request