Effect of biochar application on soil respiration in a summer maize crop after five years

A field experiment was conducted to explore the effects of biochar application on changes in soil respiration component characteristics and influencing factors in the Shihezi 121st group, Xinjiang, five years after the treatment. Five treatments were applied, namely a single application of chemical fertilizer(T0)and applications of 15.75(T1), 31.50(T2), 63.00 t·hm-2(T3), and 126.00 t·hm-2 (T4)of biochar. The diurnal dynamics of soil respiration and heterotrophic respiration in sandy soil showed a single peak curve, with the peak value appearing at approximately 13:00. The daily average respiration rate of the T4 treated soil was 2.74 μmol·m-2·s-1, which was significantly higher than that of the other treatments(P<0.05). Biochar application significantly changed soil heterotrophic respiration, while there was no significant effect on autotrophic respiration. The soil respiration rate significantly increased with the increase in the quantity of biochar and decreased with the growth period of maize. There was a significant correlation between the soil respiration rate and soil temperature at 5, 10, and 15 cm soil depths, but no significant correlation between soil respiration and soil water content. The temperature sensitivity of soil respiration increased with the increase of biochar application. Thus, biochar can change the total respiration of sandy soil in oasis farmlands by improving soil heterotrophic respiration. Biochar application also increased the temperature sensitivity of soil respiration and enhanced soil CO2 emissions.