The Environmental Impacts of the Grassland Agricultural System and the Cultivated Land Agricultural System: A Comparative Analysis in Eastern Gansu

Abstract

“Introducing grass into fields”, the major approach to modern grassland agriculture, is the crucial direction of agricultural structure adjustment in the farming-pastoral zone of Northern China. However, there have been few studies on the environmental impacts of agricultural production in this pattern. We used the life cycle assessment (LCA) method for the first time from the perspective of the entire industry chain from agricultural material production to livestock marketing, which involves the combination of planting and breeding. A comparative analysis of the environmental impact processes of beef and pork, the main products of the two existing agricultural systems in Eastern Gansu, was conducted. The findings showed that based on the production capacity of the 1 ha land system, the comprehensive environmental impact benefit of the grassland agricultural system (GAS) in the farming-pastoral zone was 21.82%, higher than that of the cultivated land agricultural system (CLAS). On Primary energy demand (PED) and environmental acidification potential (AP), the GAS needs improvement because those values were 38.66% and 22.01% higher than those of the CLAS, respectively; on global warming potential (GWP), eutrophication potential (EP), and water use (WU), the GAS performed more environment-friendlily because those values were 25.00%, 68.37%, and 11.88% lower than those of the CLAS, respectively. This indicates that a change in land use will lead to a change in environmental impacts. Therefore, PED and AP should be focused on the progress of grassland agriculture modernization by “introducing grass into fields” and new agricultural technologies.

Self‐stabilizing maintenance process in plant communities of alpine meadows under different grazing intensities

“…The Poaceae, forb, and Cyperaceae PFGs were the main components influencing aboveground biomass production by affecting plant community structure, and soil nutrient accumulation under varying grazing intensities, presumably related to the different responses of the plant community structure and aboveground biomass production to prohibited or reduced grazing in alpine meadows. These differences between the responses could be summarized as follows: first, among plant communities, the forb PFG is the largest group influencing aboveground biomass formation (Lin, 2017). It contains over 10 species located in different vertical spaces in the plant community and mixes with annual and perennial plants in alpine meadows (Harris, 2010; S. He & Richards, 2015; Pando‐Moreno et al, 2004; Wen et al, 2018; Zhou et al, 2005).…”

“…Six soil cores from the same depth were mixed to form one sample at each of the five depths in each treatment and plot. Debris was removed from the sample, and then, the sample was air‐dried and divided into two parts, which were sieved to 2 and 0.25 mm, respectively (Lin, 2017). The sample sieved through a 2 mm screen was used to determine the concentrations of soil pH, ammonium nitrogen (NH 4 + ), nitrate nitrogen (NO 3 − ), available phosphorus (avP), and available potassium (avK), while the sample sieved through a 0.25 mm screen was used to determine the concentrations of total nitrogen (TN), total phosphorus (ThP), total carbon (TC), inorganic carbon (IC), and total potassium (TK).…”

“…With gradual changes in the disturbance intensity and environmental factors (such as precipitation, soil nutrient quality and quantity, and disturbance intensity), the characteristics of ecosystems (estimated by, e.g., vegetation cover, biomass, or nutrient contents) may be relatively stable in a steady stage, but after the disturbance intensity crosses a certain threshold, the characteristics of the stage may change to a new one, which may exist much longer and be more difficult to be returned to the former stage (Scheffer et al, 2001; Xu et al, 2020). Compared with the steady stage, a regime shift takes less time (Xu et al, 2020) and results in steady stages with different ability of forage production coexisting in the same geographical and climatic environments (Lin, 2017; Lin, Li, et al, 2022). A number of studies have shown that the forage production capacity of those steady stages can be degraded under overgrazing (Lin, 2017; Lin, Li, et al, 2022).…”

“…Compared with the steady stage, a regime shift takes less time (Xu et al, 2020) and results in steady stages with different ability of forage production coexisting in the same geographical and climatic environments (Lin, 2017; Lin, Li, et al, 2022). A number of studies have shown that the forage production capacity of those steady stages can be degraded under overgrazing (Lin, 2017; Lin, Li, et al, 2022).…”

Greenhouse Gas Emissions from Beef Cattle Breeding Based on the Ecological Cycle Model

“…Global GHG emissions from livestock increased by 51% from 1961 to 2010 because of increased demand for livestock products [ 4 ], and CH 4 accounted for 50% of total emissions with 24% N 2 O and 26% CO 2 . In order to compare different animal products’ emission intensities, FAO (2021) calculated that meat from buffalo presents the highest emission intensity, with an average of 404 kg CO 2 -eq per kg of protein, followed by beef, with an average of 295 kg CO 2 -eq per kg of protein, whereas pork has much lower emission intensity, below 100 kg CO 2 -eq per kg of protein [ 5 , 6 , 7 ]. Moreover, beef and dairy cattle are the largest source of livestock emissions, i.e., 74% of global livestock emissions [ 4 ].…”