马铃薯/大豆套作对3个大豆品种光合指标和产量的影响

以大豆品种中黄30(早熟)、冀豆17(中熟)和齐黄34(晚熟)单作为对照，在大田条件下，研究马铃薯/大豆套作模式中3个品种生育期叶面积指数的变化及干物质积累的特征，分析套作马铃薯收获前后对大豆光合指标、产量及其构成因素的影响.结果表明： 生育前期阴蔽导致套作大豆叶面积指数(LAI)降低，干物质积累变缓，营养生长期相对延长，不同品种套作大豆光合速率(P_n)、蒸腾速率(T_r)和气孔导度(g_s)均低于单作.生育后期套作大豆生长加快，尤其是马铃薯收获后晚熟品种增幅显著提高.此时，套作大豆受光条件得到较大改善，表现出较强的补偿效应，LAI、干物质积累、P_n和g_s相对于单作上升幅度加大，接近于单作大豆，但不同品种补偿能力不同.与单作相比，套作模式下不同大豆品种的有效荚数、单株粒数及每荚粒数均有所降低，其中早熟品种分别显著下降22.0%、36.0%、17.6%，中熟品种下降5.1%、13.1%、8.9%，晚熟品种下降5.7%、7.6%、2.1%.套作模式下，中、晚熟大豆品种的产量较早熟品种分别高92.4%和163.4%，总土地当量比(LER)分别达到1.81和1.84.表明中、晚熟大豆品种与马铃薯组合套作优势更强，有利于马铃薯收获后大豆的补偿生长，促进套作大豆产量提高，充分发挥了复合群体的产量优势.

Effects of potato/soybean intercropping on photosynthetic characteristics and yield of three soybean varieties.

The potato/soybean intercropping trials using three soybean varieties including Zhonghuang 30 (early-maturing variety), Jidou 17 (mid maturing variety) and Qihuang 34 (late maturing variety) with the sole cropping potato as contro1 were carried out to determine the dynamic changes of leaf area index (LAI) of soybean, accumulation of dry matter, photosynthetic characte ristics, yield and yield components. The results showed that the LAI, dry matter accumulation, net photosynthesis (P_n), transpiration rate (T_r) and stomatal conduction (g_s) of soybean in all intercropping systems were lower than in monoculture because of the influence of intensified lower light during earlier growing stage, and the duration from planting to flowering was extended. When the potato was harvested, the LAI, dry matter accumulation, P_n, T_r and g_s of soybean in all intercropping systems increased, especially for mid maturing and late maturing varieties, which became much closer to those in the monoculture. Compared with sole cropping, the pods per plant, seeds per plant and seeds per pod in intercropping system significantly decreased by 22.0%, 36.0% and 17.6% for early maturing soybean, 5.1%, 13.1% and 8.9% for mid maturing soybean, 5.7%, 7.6% and 2.1% for late maturing soybean, respectively. The yields of mid maturing and late maturing varieties in intercropping systems were higher than that of the early maturing, which increased by 92.4% and 163.4%, with the land equivalent ratio (LER) of 1.81 and 1.84, respectively. This suggested that mid maturing and late maturing soybean varieties were suitable for intercropping with the potato to improve photosynthetic efficiency, dry matter accumulation and yield of intercropping soybean.