Soil CO2 emissions from summer maize fields under deficit irrigation.

Irrigation practice is one of the main factors affecting soil carbon dioxide (CO2) emission from croplands and therefore on global warming. As a water-saving irrigation practice, the deficit irrigation has been widely used in summer maize fields and is expected to adapt to the shortage of water resources in Northwest China. In this study, we examined the impacts of deficit irrigation practices on soil CO2 emissions through a plot experiment with different irrigation regimes in a summer maize field in Northwest China. The irrigation regimes consisted of three irrigation treatments: deficit irrigation treatments (T1: reduce the irrigation amount by 20%, T2: reduce the irrigation amount by 40%) and full irrigation (T0) treatments. The results showed that the soil CO2 cumulative emissions with T1 and T2 were decreased by 9.8% (p < 0.05) and 14.3% (p < 0.05), respectively, compared with T0 treatment (1365.3 kg-C ha-1). However, there were no significant differences between T1 and T2 treatments (p > 0.05). Soil CO2 fluxes with different irrigation treatments showed significant correlations with soil moisture (p < 0.001) and soil temperature (p < 0.05). It was also observed that summer maize yields with T1 and T2 treatments were reduced by 4.9% (p > 0.05) and 30.9% (p < 0.05), compared with T0 (34.3 t ha-1), respectively. The findings demonstrate that the deficit irrigation treatment (T1) resulted in a considerable decrease in soil CO2 emissions without impacting the summer maize yields significantly. The results could be interpreted to develop better irrigation management practices aiming at reducing soil CO2 emissions, saving water, and ensuring crop yield in the summer maize fields in Northwest China.

Deficit irrigation effectively reduces soil carbon dioxide emissions from wheat fields in Northwest China.

BACKGROUND: An irrigation regime is an important factor in regulating soil CO2 emissions from wheat fields. Deficit irrigation can be applied easily in the fields and has been implemented in northwest China. Previous studies have mainly focused on the effects of deficit irrigation on crop yield and quality. Studies on its environmental impacts are sparse. RESULTS: Soil CO2 fluxes from deficit-irrigated fields were lower than those from full irrigation (CK) during most of the growing season. Cumulative soil CO2 emissions from deficit-irrigated fields were reduced by 10.2-25.5%, compared with the CK. Peaks of soil CO2 fluxes were observed 3-7 days after irrigation in the water-filled pore space (WFPS) range of 65.7-80.4%. Under different irrigation regimes, significant positive correlations were observed between soil CO2 fluxes and WFPS (P < 0.01), but no significant correlations were found between soil CO2 fluxes and soil temperature. Compared to CK, yields for the T1, T2, and T4 were significantly reduced (P < 0.05) but the yield for T3 was only reduced by 2.3% (P > 0.05); T3 significantly reduced soil CO2 emissions by 10.2% (P < 0.05) and reduced the irrigation water amount by 5.7%. CONCLUSION: Deficit irrigation effectively reduced CO2 emissions from winter wheat field soils. T3 may be a water-saving, CO2 emission-reducing and high-yield irrigation regime for winter wheat fields in northwest China. The research laid a preliminary theoretical foundation for formulating winter wheat irrigation systems that are water saving, emission reducing, and that produce high yields. © 2019 Society of Chemical Industry.

Role of the PEBP4 protein in the development and metastasis of gastric cancer.

Phosphatidylethanolamine-binding protein 4 (PEBP4) has previously been reported to be upregulated in various cancers. However, the physiological functions of PEBP4 in gastric cancer are still unknown. Aiming to clarify the properties and role of PEBP4 in the development and invasion of gastric cancer, we performed several biological assays and a knockdown assay. The expression level of PEBP4 was shown to be significantly upregulated in gastric cancer tissue samples, and knockdown of the expression of PEBP4 induced significant inhibitory effects on cell proliferation, migration and invasiveness. In addition, it was demonstrated that PEBP4 was associated with the development and invasion of gastric cancer cells through activation of the PI3K/Akt signaling pathway. Our findings supported the hypothesis that PEBP4 might be a novel potential drug target for the treatment of gastric cancer.

Seasonal variations of CH4 and N2O emissions in response to water management of paddy fields located in Southeast China.

Water management is one of the most important practices that affect methane (CH(4)) and nitrous oxide (N(2)O) emissions from paddy fields. A field experiment was designed to study the effects of controlled irrigation (CI) on CH(4) and N(2)O emissions from paddy fields, with traditional irrigation (TI) as the control. The effects of CI on CH(4) and N(2)O emissions from paddy fields were very clear. The peaks of CH(4) emissions from the CI paddies were observed 1-2d after the water layer disappeared. Afterward, the emissions reduced rapidly and remained low until the soil was re-flooded. A slight increase of CH(4) emission was observed in a short period after re-flooding. N(2)O emissions peaks from CI paddies were all observed 8-10d after the fertilization at the WFPS ranging from 78.1% to 85.3%. Soil drying caused substantial N(2)O emissions, whereas no substantial N(2)O emissions were observed when the soil was re-wetted after the dry phase. Compared with TI, the cumulative CH(4) emissions from the CI fields were reduced by 81.8% on the average, whereas the cumulative N(2)O emissions were increased by 135.4% on the average. The integrative global warming potential of CH(4) and N(2)O on a 100-year horizon decreased by 27.3% in the CI paddy fields, whereas no significant difference in the rice yield was observed between the CI and TI fields. These results suggest that CI can effectively mitigate the integrative greenhouse effect caused by CH(4) and N(2)O emissions from paddy fields while ensuring the rice yield.