[Responses of soil respiration to temperature under different mulching modes in a dryland corn field]

Based on a 9-year field experiment, soil samples under straw mulching (SM), plastic film mulching (FM) and no mulching (CK) were incubated at 15, 25 and 35 ℃ for 60 d to investigate the responses of soil respiration to warming and its temperature sensitivity. The results showed that during the whole incubation period, soil respiration rate exhibited a unimodal distribution, while the cumulative soil respiration increased with an "S" curve. The cumulative soil respiration during the first 30 d accounted for about 75%-85% of total during the whole incubation period. The cumulative SM increased by 19.4% compared with CK, whereas no difference was detected between CK and FM. At 25 ℃ and 35 ℃, the mean soil respiration rate increased by 17.0% and 36.8%, and the cumulative CO₂ release of soil respiration increased by 13.1% and 33.6%, respectively, compared with 15 ℃. No interaction was detected between mulching method and temperature. 97.7%-99.9% of variation in soil respiration could be explained by temperature change, with soil respiration being positively correlated with organic carbon and total nitrogen content. Compared with no mulching and plastic film mulching, straw mulching could significantly promote soil respiration by increasing the input of organic matter in the soil, but reduced the temperature sensitivity of soil respiration. Straw mulching rather than plastic film mulching would be more efficient at reducing CO₂ emission in the Loess Plateau dryland farming area under the context of global warming.