Home courtyard agriculture is an important model of agricultural production on the Tibetan plateau. Be- cause of the sensitive and fragile plateau environment, it needs to have optimal performance characteristics, inc...Home courtyard agriculture is an important model of agricultural production on the Tibetan plateau. Be- cause of the sensitive and fragile plateau environment, it needs to have optimal performance characteristics, including high sustainability, low environmental pressure, and high economic benefit. Emergy analysis is a promising tool for evaluation of the environmental-economic performance of these production systems. In this study, emergy analysis was used to evaluate three courtyard agricultural production models： Raising Geese in Corn Fields （RGICF）, Con- ventional Corn Planting （CCP）, and Pea-Wheat Rotation （PWR）. The results showed that the RGICF model produced greater economic benefits, and had higher sustainability, lower environmental pressure, and higher product safety than the CCP and PWR models. The emergy yield ratio （EYR） and emergy self-support ratio （ESR） of RGICF were 0.66 and 0.11, respectively, lower than those of the CCP production model, and 0.99 and 0.08, respectively, lower than those of the PWR production model. The impact of RGICF （1.45） on the environment was lower than that of CCP （2.26） and PWR （2.46）. The emergy sustainable indices （ESIs） of RGICF were 1.07 and 1.02 times higher than those of CCP and PWR, respectively. With regard to the emergy index of product safety （EIPS）, RGICF had a higher safety index than those of CCP and PWR. Overall, our results suggest that the RGICF model is advantageous and provides higher environmental benefits than the CCP and PWR systems.展开更多
Determining how agricultural management practices affect soil phosphorus(P) over the winter may further our understanding of the soil P cycle under specific environmental conditions in eastern Canada. This study asses...Determining how agricultural management practices affect soil phosphorus(P) over the winter may further our understanding of the soil P cycle under specific environmental conditions in eastern Canada. This study assessed changes over winter for soil P fractions and other selected chemical properties as affected by tillage and P fertilization. In 1992, a long-term corn(Zea mays L.) and soybean(Glycine max L.) rotational experiment was established in the province of Quebec, Canada. Soil samples(0–15 cm) were collected in fall 2001 and 2007 after a soybean harvest, and in the following spring 2002 and 2008 before corn seeding, in main plots under moldboard plow and no-till managements and selected subplots fertilized with 0, 17.5, or 35 kg P ha-1and 160 kg N ha-1. Soil samples were analyzed for P fractions and other chemical properties to assess changes over winter for 2001–2002 and 2007–2008. Changes over winter of all soil P fractions were significant for the two periods, indicating the occurrence of soil P transformation and movement over winter. The Mehlich-3-extractable Fe, Al, Ca, and Mg decreased during the two studied periods. Tillage had no significant effect on all soil P fractions. The resin-extractable P in 2001–2002 and Na HCO3-extractable inorganic P and Na OH-extractable organic P during the two winters were significantly increased under P fertilization. This study demonstrated that P in cultivated soils changed during winter as a result of changes in labile P fractions possibly due to the solubilization of residual fertilizer P combined with environmental factors.展开更多
基金supported by the National Natural Science Foundation of China(No.31201594)the Science and Technology Service Network Initiative of CAS(No.KFJ-EW-STS-073)the Development Platform of Wild Characteristic Biological Resources in Tibet Autonomous Region,China
文摘Home courtyard agriculture is an important model of agricultural production on the Tibetan plateau. Be- cause of the sensitive and fragile plateau environment, it needs to have optimal performance characteristics, including high sustainability, low environmental pressure, and high economic benefit. Emergy analysis is a promising tool for evaluation of the environmental-economic performance of these production systems. In this study, emergy analysis was used to evaluate three courtyard agricultural production models： Raising Geese in Corn Fields （RGICF）, Con- ventional Corn Planting （CCP）, and Pea-Wheat Rotation （PWR）. The results showed that the RGICF model produced greater economic benefits, and had higher sustainability, lower environmental pressure, and higher product safety than the CCP and PWR models. The emergy yield ratio （EYR） and emergy self-support ratio （ESR） of RGICF were 0.66 and 0.11, respectively, lower than those of the CCP production model, and 0.99 and 0.08, respectively, lower than those of the PWR production model. The impact of RGICF （1.45） on the environment was lower than that of CCP （2.26） and PWR （2.46）. The emergy sustainable indices （ESIs） of RGICF were 1.07 and 1.02 times higher than those of CCP and PWR, respectively. With regard to the emergy index of product safety （EIPS）, RGICF had a higher safety index than those of CCP and PWR. Overall, our results suggest that the RGICF model is advantageous and provides higher environmental benefits than the CCP and PWR systems.
基金supported by Agriculture and Agri-Food Canada(AAFC)the MOE(Ministry of Education of China)-AAFC Ph.D.Research Program
文摘Determining how agricultural management practices affect soil phosphorus(P) over the winter may further our understanding of the soil P cycle under specific environmental conditions in eastern Canada. This study assessed changes over winter for soil P fractions and other selected chemical properties as affected by tillage and P fertilization. In 1992, a long-term corn(Zea mays L.) and soybean(Glycine max L.) rotational experiment was established in the province of Quebec, Canada. Soil samples(0–15 cm) were collected in fall 2001 and 2007 after a soybean harvest, and in the following spring 2002 and 2008 before corn seeding, in main plots under moldboard plow and no-till managements and selected subplots fertilized with 0, 17.5, or 35 kg P ha-1and 160 kg N ha-1. Soil samples were analyzed for P fractions and other chemical properties to assess changes over winter for 2001–2002 and 2007–2008. Changes over winter of all soil P fractions were significant for the two periods, indicating the occurrence of soil P transformation and movement over winter. The Mehlich-3-extractable Fe, Al, Ca, and Mg decreased during the two studied periods. Tillage had no significant effect on all soil P fractions. The resin-extractable P in 2001–2002 and Na HCO3-extractable inorganic P and Na OH-extractable organic P during the two winters were significantly increased under P fertilization. This study demonstrated that P in cultivated soils changed during winter as a result of changes in labile P fractions possibly due to the solubilization of residual fertilizer P combined with environmental factors.
