Abstract: 【Objective】To explore the mechanism of a high yield and an optimum spatial-temporal configuration management in potato-soybean intercropping system. 【Method】This study takes a potato-soybean intercropping system with wildly-used and an apparent yield advantage in Northwest irrigation districts as the research object, a field experiment was conducted in two consecutive seasons (2012-2013), 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 the control were carried out to determine the dynamic changes of growth stages of soybean, leaf area index, accumulation of dry matter, photosynthetic characteristics, yield components and yieldin order to optimize the reasonable group configuration.【Result】In comparison with the sole cropping, intercropping system led to a delayed reproductive growth stage of soybean but did not change the whole growth period, the duration from planting to flowering was extended, but the duration from flowering to maturing was shortened. The co-growth stage of different soybean varieties was not affected by intercropping, but the reproductive co-growth stage (from flowering to maturing) was remarkable (P＜0.05, late maturing variety was 12 days, middle-maturing variety was 36 days, early-maturing variety was 42 days).There was a lower increase under intercropping than under sole cropping, the LAI of the late-maturing variety was lower than the mid-maturing and early maturing varieties, significantly (P＜0.05) during earlier growing stage but higher after the potato had been harvested. There was a significant difference in dry matter accumulation between intercropping and sole cropping during the earlier growing stage, dry matter accumulation of inter-soybean relative to the sole soybean was decreased by 55.73% at 60 days after soybean sowing. The Pn varied considerably by different potato-soybean intercropping systems, and lower than the sole soybean, which the late-maturing variety was higher than the mid-maturing and early maturing varieties significantly (P＜0.05).When the potato had been harvested (100 days after soybean sowing), the dry matter accumulation and Pn of soybean in all intercropping systems increased, especially mid-maturing and late-maturing varieties, which became much closer to the sole cropping. Compared with sole cropping, the pods per plant, seeds per plant, and seeds per pod of early-maturing soybean in the intercropping system decreased by 24.15%, 22.14% and 18.92%, respectively (P＜0.05). However, effective pods per plant, seeds per plant, and seeds per pod of the late-maturing soybean decreased by 5.66%, 7.64% and 2.11%, respectively. Finally, the yield of the mid-maturing and late-maturing varieties in intercropping systems are higher than the early-maturing, which increased by 79.85% and 145.08%, with the land equivalent ratio (LER) of 1.77 and 1.83, respectively. 【Conclusion】Mid-maturing and late-maturing varieties were a suitable plant type configuration, the whole growth period was longer, the duration from planting to flowering was extended, but the duration from flowering to maturing was shortened, which could improve the leaf area index, photosynthetic efficiency for compensatory growth when the potato had been harvested, showing the stronger intercropping superiority.

Key words: potato, soybean, intercropping, photosynthetic characteristics, yield, compensation effect