Agricultural production in Minqin Oasis, China, is commonly categorized as intensive crop production (ICP), integrated crop–livestock production (ICLP), intensive livestock production (confined feeding) (IFLP), and extensive livestock production (grazing) (EGLP). The objectives of the present study were to use a life cycle assessment technique to evaluate on-farm energy balances and greenhouse gas (GHG) emissions of agricultural production, and to compare the differences among the four systems. Data used in the present study were collected from published literature and face-to face questionnaires from 529 farms in eight towns (two towns per production system) within Minqin county. The ANOVA of averaged data from 2014 to 2015 indicated that the net energy ratio (Output/Input) for the EGLP system was significantly higher than that for any other system ( P < 0.01), whereas the difference among other three systems were not significant. The EGLP system generated lower CO 2 -eq emissions per hectare of farmland than other systems ( P < 0.01). Relating carbon economic efficiency to market values (US$) of agricultural products, indicated that the carbon economic efficiency (US$/kg CO 2 -eq) of the IFLP system was significantly greater than that of other systems ( P < 0.01). The major GHG emission sources varied across the systems, that is, soil respiration is the dominant source in EGLP, while the main sources in IFLP are enteric methane and manure management; in ICLP major sources are enteric methane, soil respiration and fertilizer; and in ICP are soil respiration and fertilizer. The structural equation modelling analysis showed that livestock category was strongly linked to net income. The direct effects and total effects of water use efficiency, via its positive influence on energy balances and GHG emissions were much stronger than those of other dependent variables. The study provides important benchmark information to help develop sustainable agricultural production systems on energy balances and GHG emissions in northwestern China.
The aim of this study is to explore the spatiotemporal variation and the transfer of ecosystem service value (ESV) in Jiuquan City from 2005 to 2020 to help ecological development. Based on the equivalent factor method and the grid analysis, employed to analyze the spatial and temporal changes in ecosystem service values in Jiuquan City, the fracture point model and the field strength model were applied to calculate the transfer of ecosystem service value in seven districts and counties of Jiuquan City. The ESV of Jiuquan City showed an overall increasing trend, and all individual ESVs showed increasing trends, except for water supply, with the ESV of regulating services showing the most significant growth from 2005 to 2020. The top three secondary ESVs were hydrological regulation, climate regulation, and environmental purification, with regulatory services accounting for the largest proportion, followed by support services, supply services, and cultural services. From 2005 to 2020, the distribution of high and low ESV zones in Jiuquan City did not change significantly, with the high-value zones being mainly located in Suzhou District, south of Subei County and Yumen City, and the low-value zones being concentrated in Dunhuang City, Guazhou County, north of Suebei County, and Jinta County. The ESVs transfers from each district in the study area, in descending order, were Guazhou County, Subei County, Yumen City, Dunhuang City, Aksai County, Jinta County, and Suzhou District. Guazhou and Subei were the main ESV exporters. Areas with high ESV exports tended to have high ESV values. Hydrologic regulation is the service type with the largest transfer volume, accounting for 19.00% of the total ESV transfer in Jiuquan. Jiuquan possesses the highest ecosystem service value in the Gansu Province, China, indicating a superior ecological status.
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