调控措施对祁连山中度退化高寒草甸土壤的影响

研究不同调控措施(春季休牧、春季休牧-划破草皮、春季休牧-划破草皮-施肥、春季休牧-划破草皮-播种、春季休牧-划破草皮-施肥-播种)对祁连山中度退化高寒草甸植被、土壤理化性质和土壤微生物生物量的影响。结果表明: 各调控措施均显著增加了退化高寒草甸植被盖度以及地上、地下生物量,春季休牧-划破草皮-施肥与春季休牧-划破草皮-施肥-播种两种措施下植被物种丰富度显著增加,春季休牧-划破草皮-播种与春季休牧-划破草皮-施肥-播种措施下物种优势种为补播草种青海草地早熟禾。中度退化高寒草甸土壤(对照)pH和容重显著高于各调控措施样地,春季休牧-划破草皮-施肥-播种措施下土壤含水量、土壤有机碳、全氮、全钾含量及碳氮比、氮磷比均最高,分别为21.3%、22.30 g·kg^-1、2.77 g·kg^-1、19.93 g·kg^-1、8.3、3.5。春季休牧-划破草皮-施肥-播种措施下退化草地土壤微生物生物量氮、磷(分别为104.98和40.74 mg·kg^-1)显著高于其他措施,而退化草地在春季休牧-划破草皮-施肥措施下土壤微生物生物量碳(240.72 mg·kg^-1)显著高于其他措施。雷达图表明,调控措施对退化草地植被特征(地上、地下生物量)、土壤理化性质(含水量、有机碳、全氮、全磷、全钾)及土壤微生物生物量(碳、氮、磷)特征影响显著,且春季休牧-划破草皮-施肥-播种措施对研究区退化草地的修复效果最佳。

Effects of regulation measure on soil and microbial biomass of moderately degraded alpine meadow in Qilian Mountain,China

We examined the effects of different regulation measures (spring rest grazing, spring rest grazing-cutting turf, spring rest grazing-cutting turf-fertilization, spring rest grazing-cutting turf-sowing, spring rest grazing-cutting turf-fertilization-sowing) on vegetation, soil physical and chemical properties, and soil microbial biomass in mode-rately degraded alpine meadow in Qilian Mountain. The results showed that all the regulation measures significantly increased plant coverage and aboveground and underground biomass of degraded alpine meadows. Plant species richness increased significantly under the two measures of spring rest grazing-cutting turf-fertilization and spring rest grazing-cutting turf-fertilization-sowing. The dominant species of spring rest grazing-cutting turf-sowing and spring rest grazing-cutting turf-fertilization-sowing was Poa pratensis cv. Qinghai. Soil pH and bulk density in moderately degraded alpine meadow (control) were significantly higher than those of all regulation measures. Soil water content, soil organic carbon, total nitrogen and total potassium, carbon-nitrogen ratio and nitrogen-phosphorus ratio of spring rest grazing-cutting turf-fertilization-sowing measures were the highest, which were 21.3%, 22.30 g·kg^-1, 2.77 g·kg^-1, 19.93 g·kg^-1, 8.3 and 3.5, respectively. Soil microbial biomass nitrogen and phosphorus (104.98 and 40.74 mg·kg^-1) of degraded meadows under spring rest grazing-cutting turf-fertilization-sowing measures were significantly higher than those of other measures, while soil microbial biomass carbon (240.72 mg·kg^-1) of degraded meadows under spring rest grazing-cutting turf-fertilization measures was significantly higher than that of other measures. The results of radar map showed that the regulation measures affected the characteristics of degra-ded meadow vegetation (aboveground and underground biomass), soil physical and chemical properties (water content, organic carbon, total nitrogen, total phosphorus, and total potassium) and soil microbial biomass (carbon, nitrogen and phosphorus). Spring rest grazing-cutting turf-fertilization-sowing measures had the best performance in restoraing degraded meadows in the study area.