This study investigated the effects of different addition levels （0， 2.5， 5.0， 7.5 g） of Seriphidium transiliense leaf litter on the enzyme activities and stoichiometric ratios of β-1，4-glucosidase （βG）， N-acetyl-β-glucosaminidase （NAG）， leucine aminopeptidase （LAP）， and alkaline phosphatase （AP） in 100.0 g of soil from Sagebrush desert grassland during 320 d （T₁）， 410 d （T₂）， and 500 d （T₃） of decomposition using an outdoor Mason jar incubation method. The results showed that enzyme activities generally decreased over the decomposition period. Specifically， the βG activity in the 5.0 g treatment at T₂ was significantly higher than that at T₁ and T₃ by 12.16% and 20.53%， respectively （P<0.05）. The NAG activity in the 7.5 g treatment at T₁ was significantly higher than that at T₂ and T₃ by 19.19% and 19.10%， respectively （P<0.05）. Enzyme activities initially decreased and then increased with increasing litter addition. At T₃， the 7.5 g treatment significantly enhanced NAG activity while reducing LAP activity （P<0.05）. The average soil enzyme stoichiometric ratios of C∶N， C∶P， and N∶P were 0.65， 0.91， and 1.41， respectively， with a C∶N∶P stoichiometric ratio of 1∶1.26∶1.05， with the vector angles less than 45°. In conclusion， soil enzyme activities and their stoichiometric ratios were co-regulated by both litter addition amount and decomposition stage， and were constrained by soil nitrogen limitation.

Litter  /  Sagebrush desert grassland  /  Stoichiometric ratio  /  Soil enzyme activitie