Abstract: To get the suitable cultivation measures to increase summer soybean yield as well as efficiency and realize carbon sequestration in cropland under drip irrigation in Yili River valley, northern Xinjiang, we set up four kinds of soil tillage measures including tillage (T), subsoiling tillage (ST), tillage with plastic film (TP), and no-tillage (NT) in 2017 under the drip irrigation condition. We examined the changes of soil respiration, carbon emissions, plant carbon sequestration, economic benefits and yield of summer soybean cropland in northern Xinjiang. The results showed that the peak value of soil respiration in different tillage measures occurred from flowering stage to pod-bearing stage. Soil respiration rate, total respiration rate, total plant carbon sequestration and yield of summer soybean were the highest in tillage with plastic film, followed by subsoiling tillage, which were significantly higher than that in tillage and no-tillage, with the lowest under no-tillage. Carbon balance of summer soybean cropland ecosystem under different tillage measures was positive. Among various inputs of agricultural production means, the irrigation electricity had the highest carbon emission, accounting for 54.33%-65.24% of the total under each treatment. The carbon emission and cost input of the agricultural production means in TP were significantly different from other three treatments due to the increased input of mulching film (P<0.05). The results showed that subsoiling had the highest economic benefits and net carbon absorption, followed by tillage with plastic film. Further, subsoiling had the best carbon productivity, carbon economic benefits and carbon ecological benefits. The overall performance was ST>TP>T>NT. Subsoiling tillage and plastic film with tillage can significantly improve carbon sequestration and production efficiency in cropland ecosystem. Considering the economic benefits, production input and recovery rate of plastic film, subsoiling tillage has the maximum net carbon absorption, optimal economic benefits and carbon efficiency value, and thus it has a priority for application to increase production efficiency and carbon sequestration in this region.

Key words: sunlight greenhouse, simulation model, cucumber, dry matter allocation, growth and development