大麦/玉米间作优势及地上部和地下部因素的相对贡献研究

Intercropping Advantage and Contribution of Above-Ground and Below-Ground Interactions in the Barley-Maize Intercropping

采用田间微区试验以及地下部种间根系分隔技术研究了玉米覆膜与不覆膜两种情况下大麦/玉米间作优势以及地上部和地下部因素对间作优势的相对贡献。结果表明,玉米不覆膜时,大麦/玉米间作籽粒和生物产量的LER均为1.06,无明显间作优势;玉米覆膜时,大麦/玉米间作籽粒和生物产量的LER分别为1.32和1.30,具有显著的间作优势。玉米不覆膜时,大麦/玉米间作系统养分吸收优势不显著;玉米覆膜时,间作系统具有显著的养分吸收优势。地上部和地下部因素对大麦/玉米间作中籽粒和生物产量间作优势的相对贡献,当玉米不覆膜时为间作劣势而无贡献;当玉米覆膜时,地上部、地下部因素对间作优势的相对贡献分别为80%和20%。当玉米覆膜时,地上部和地下部交互作用对间作氮素养分吸收的贡献具有同等重要性(各占50%);对磷吸收的贡献分别占60%与40%,钾则分别为45%与55%。

A microplot experiment and a root barrier technique were employed to investigate the intercropping advantage and the relative contribution of above- and below-ground interactions to the yield and nutrient uptaking in the barley-maize intercropping system with or without plastic sheet mulching. The results showed that the land equivalent ratios （LERs） of both grain yield and biomass were around 1 （average 1.06） for the intercropping of barley and maize without plastic sheet mulching, showing a yield disadvantage of the intercropping. In contrast, LERs with plastic sheet mulching were 1.32 for grain yield and 1.30 for biomass, indicating a significant yield advantage of the intercropping. There was no significant advantage of nutrient uptaking in the intercropping of barley and maize without plastic sheet mulching, whereas there was significant advantage of nutrient uptaking in the intercropping with plastic sheet mulching. The contribution of above-ground and below-ground interactions to the intercropping advantage of grain yield were 80% and 20%, respectively, for the intercropping with plastic sheet mulching. Similar results were observed for above-ground biomass. The contribution of above-ground and below-ground interactions to the increase of nutrient uptaking were 50% and 50% for nitrogen, 60% and 40% for phosphorus, 45% and 55% for potassium respectively, when intercropped maize was mulched with plastic sheet.