Time between two partial rewetting events influences the respiration flush and microbial growth after the final rewetting

Abstract The effect of rapid rewetting dry soil to a water content optimal for microbial activity on respiration and nutrient cycling has been extensively studied. However, with smaller rainfall events, may also rewet more slowly an interval between partial events. In this experiment, unamended or amended faba bean residue (C/N 9) was incubated at 50% water-holding capacity (WHC) 2 weeks, then the treatments air-dried weeks. Then, exposed six treatments: rapidly WHC once day 0 (RR50), partially 25% (PR25), by two applications each first second after 6 h (SR6), 12 (SR12), 36 (SR36), 60 (SR60). Constantly moist (CM) kept throughout experiment. flush final followed order SR6 > RR50 SR12 SR36 PR25, SR60. Microbial biomass C decreased in PR25 SR SR60, CM. We conclude that slow can increase compared rewetting, but only if occurs first. size increasing time