摘要:以宁夏荒漠草原柠条锦鸡儿（Caragana kornshinskii）枯落物为研究对象，利用网孔分解袋法研究了极小型、小型、中型和大型柠条锦鸡儿灌丛微生境枯落物分解率变化特征及对土壤环境的响应规律。结果表明：（1）随着分解时间延长，不同大小柠条锦鸡儿灌丛微生境土壤含水量和土壤温度均呈现出相似的分布特征，而土壤pH值和电导率随时间分布特征则受到灌丛大小的显著影响。（2）3种网孔内，不同大小柠条灌丛微生境间枯落物分解率均无显著差异性。但是，灌丛微生境中枯落物分解率受到灌丛大小和网孔大小的共同影响。（3）中型灌丛微生境中枯落物分解率在3种网孔间均无显著差异性。但在极小型灌丛微生境中，120 d时枯落物分解率表现为4 mm（40.95%） > 0.01 mm（38.51%） > 2 mm（32.14%），150 d时枯落物分解率表现为2 mm（37.64%） > 4 mm（35.20%） > 0.01 mm（26.68%）。在小型灌丛微生境中，120 d时枯落物分解率表现为0.01 mm（46.81%） > 4 mm（41.07%） > 2 mm（34.75%）。在大型灌丛微生境中，120 d时枯落物分解率表现为4 mm（39.65%） > 2 mm（36.65%） > 0.01 mm（35.96%），210 d时枯落物分解率表现为2 mm（48.05%） > 4 mm（35.96%） > 0.01 mm（30.80%）。（4） Olson衰减指数模型得出枯落物分解50%和95%所需时间，表现为极小型灌丛和中型灌丛微生境中均为0.95年和4.1年（3种网孔相同）；小型灌丛微生境中为0.63年和2.74年（4 mm）、1.90年和8.21年（2 mm）、0.95年和4.1年（0.01 mm）；大型灌丛微生境中为0.95年和4.1年（4 mm）、0.63年和2.74年（2 mm）、1.90年和8.21年（0.01 mm）。研究表明，在宁夏荒漠草原，仅灌丛大小引起的微生境差异对枯落物分解率影响较小，但灌丛大小和土壤动物类群的相互作用对枯落物分解率的影响较大。



Abstract:In Yanchi County, Ningxia, the decomposition rates of C. korshinskii litter and the associated soil environment were sampled in microhabitats beneath very small, small, medium, and large shrub canopy sizes. Our study found that (1) during the decomposition process, soil moisture content and soil temperature indicated similar distributions in the four types of shrub canopy size, however, soil pH and soil electrical conductivity changed significantly among the four types. (2) no significant differences within the three mesh sizes between the four types of shrub canopy size in the decomposition rate of shrub litter in the litter bag was found. (3) no significant differences in the litter decomposition rate of shrubs in the litter bag within the three mesh sizes in the medium shrub microhabitat was found. In the very small shrub microhabitat, the decomposition rate of shrub litter within the three mesh sizes were 4 mm (40.95%) > 0.01 mm (38.51%) > 2 mm (32.14%) at 120 d. However, it followed the order of the three mesh sizes of 2 mm (37.64%) > 4 mm (35.20%) > 0.01 mm (26.68%) at 150 d. In the small shrub microhabitat, the decomposition rate of shrub litter within the three mesh sizes followed the order of 0.01 mm (46.81%) > 4 mm (41.07%) > 2 mm (34.75%) at 120 d, whereas it was found to follow the order of the three mesh sizes, being 2 mm (37.64%) > 4 mm (35.20%) > 0.01 mm (26.68%) at 150 d. In the large shrub microhabitat, the decomposition rate of shrub litter within three mesh sizes was 4 mm (39.65%) > 2 mm (36.65%) > 0.01 mm (35.96%) at 120 d. However, it was found to follow the order of the three mesh sizes, being 2 mm (48.05%) > 4 mm (35.96%) > 0.01 mm (30.80%) at 150 d. (4) according to the Olson index, it took 0.95 and 4.1 years for C. korshinskii litter within the three-size meshes to decompose at 50% and 95% respectively in the microhabitats of very small and medium shrub sizes. The litter in the small shrub microhabitats spent 0.63 a and 2.74 a (4 mm), 1.90 a and 8.21 a (2 mm), and 0.95 a and 4.1 a (0.01 mm), of the large shrub size spent 0.95 a and 4.1 a (4 mm), 0.63 a and 2.74 a (2 mm), and 1.90 a and 8.21 a (0.01 mm) with decomposition rates of 50% and 95%. It was concluded that differences in shrub canopy size microhabitats indicated little influence on litter decomposition rates. The results of this study suggest that the interaction between shrub size and soil faunal groups influences the litter decomposition process in the desert grassland ecosystems of Ningxia.





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