Diurnal and seasonal CO2 exchange and yield of maize cropland under different irrigation treatments in semiarid Inner Mongolia

Ecological restoration and rising CO2enhance the carbon sink, counteracting climate change in northeastern China

“…In addition, the carbon sink rate in cropland also increased considerably in the BTSSCP zone (figure 6). The increase in the cropland carbon sink was primarily related to improved irrigation technology , Peng et al 2021, optimized fertilization (Lu et al 2009, longtime wheat-maize rotation (Wang et al 2015, Xue et al 2018 and the implementation of straw return (Lu et al 2009. However, uncertainty still exists about the effectiveness of cropland carbon sequestration, as straw return may increase greenhouse gas emissions (Lu et al 2010).…”

Spatio-Temporal Variation and Future Sustainability of Net Primary Productivity from 2001 to 2021 in Hetao Irrigation District, Inner Mongolia

“…The mean NPP value in July 2018 reached its maximum at 17.726 gCm −2 (Figure 2b). It is noteworthy that the NPP changes observed every 8 days exhibit a serrated "∧"-shaped fluctuation, primarily due to short-term variations influenced by factors such as weather and solar radiation intensity [10][11][12]40]. However, the monthly variation of NPP in the Hetao Irrigation District of Inner Mongolia from 2001 to 2021 shows a relatively smooth curve, with peak values occurring in July or August each year (Figure 3a).…”

“…The overall trends on an 8-day and monthly basis exhibit a periodic "∧"-shaped pattern with peaks typically occurring at the end of July or beginning of August every year, NPP values remain close to 0 from late October to early March of the following year (Figures 2 and 3). Peng et al [10] researching in the Hetao Irrigation District of Inner Mongolia found that vegetation experiences its peak growth, and photosynthetic capacity is at its strongest around July each year. Studies by Zhang et al [36] have indicated that young vegetation in agricultural ecosystems demonstrates limited carbon assimilation capacity.…”

“…Initially, the "bottom-up" method involved setting fixed ranges as study areas and acquiring NPP through continuous observation and surveys [6][7][8][9]. For example, widely used in agricultural greenhouse gas flux studies, the chamber method system has been extensively applied [10]. In previous studies, improvements were made to the commonly used chamber method system, successfully applied in field experiments, and yielding certain results (e.g., [10][11][12][13]).…”

“…For example, widely used in agricultural greenhouse gas flux studies, the chamber method system has been extensively applied [10]. In previous studies, improvements were made to the commonly used chamber method system, successfully applied in field experiments, and yielding certain results (e.g., [10][11][12][13]). However, challenges persist in meeting regional-scale demands.…”