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Drivers of soil respiration (R s ) in farmland ecosystem have already been widely studied. However, the relationship between R s and soil fauna (F s ), hydrothermic factor in the triple intercropping system remains poorly known. An LI-6400 XT portable photosynthesis measurement system equipped with a soil respiratory chamber was adopted in the experimental field. Straw mulching treatment increased soil respiration rate but ridge tillage treatment did not have a consistent effect. A regression analysis of the relationship revealed that exponential equation fitted well the relationship between R s and soil temperature at 10 cm soil depth. However, the relationship between R s and soil moisture was best confirmed by a parabolic function. The common dominant groups of F s in wheat, corn, and soybean farmland were Collembola and Acarina, while Diptera emerged in the two rear crops farmlands. Compared to the control, ridge tillage reduced the number of F s , but straw mulching increased it and improved the index of soil fauna diversity. In conclusion, the higher was the amount of animals being active above soil surface, the stronger was the soil respiration.

Glycinebetaine acts as an osmoprotectant and is closely related with drought resistance. In the present study, glycinebetaine (GB) was exogenously-applied to two contrasting maize cultivars, Dongdan-60 and ND-95, to see whether GB improves drought resistance. Maize cultivars were grown with normal water supply till the heading stage and then exposed to two levels of soil moisture, well-watered control and drought-stressed, and then GB solution of 100 mmol was foliar applied five days after moisture treatments were imposed. The gas exchange and chlorophyll concentration were substantially declined in both maize cultivars under water stressed conditions. However, this reduction was less in Dongdan-60 than ND-95. Nonetheless, GB-treated plants considerably maintained higher gas exchange rate and chlorophyll concentration during drought stress than non-GB treated plants. The GB-induced improvement in gas exchange and chlorophyll synthesis under water stress ultimately resulted in improved growth and yield in both maize cultivars. Furthermore, the positive responses to exogenous GB application were more pronounced in Dongdan-60 as compared to ND-95 in all traits examined under water-deficit con ditions. In conclusion, exogenously applied GB to maize crops could improve gas exchange, chlorophyll synthesis, growth and yield of maize.