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荒漠植物“肥岛”效应对土壤养分空间分布的影响

Effects of “Fertilizer Island” Effect of Desert Plants on Spatial Distribution of Soil Nutrients

  • 摘要: 为探究古尔班通古特沙漠2种灌木不同空间位置“肥岛”效应,以该沙漠优势灌木——准噶尔无叶豆(Eremosparton songoricum)和沙拐枣(Calligonum mongolicum)为研究对象,以灌木根部为中心按20(A)、60(B)、100(C)、140 cm(D)向外延伸设置样点,每个样点按3个土层深度(0 3 -)质量分数显著高于准噶尔无叶豆(P<0.05)。(2)2种灌木的土壤SOM、AK、TN和全磷(TP)的富集率均呈现一致的变化趋势,即随着灌丛中心向外土壤养分富集率逐渐降低,且随着土层深度的增加土壤养分富集率呈递减趋势。(3)不同空间位置土壤养分的富集率与植株株高、冠幅有较显著的相关性(P<0.05),准噶尔无叶豆和沙拐枣的株高、冠幅与土壤SOM、TN、N-NO 3 -富集率均呈显著性正相关关系。总体来说,2种植物均呈现出了“肥岛”效应,土壤养分在不同空间分布中有明显的空间异质性,不同植物对土壤养分的富集能力不同,形成的“肥岛”效应也不同,具有明显的物种效应。

     

    Abstract: In order to explore the the “fertilizer island” effect in different spatial positions of two shrubs in the Gurbantunggut Desert,the dominant shrubs in the desert-Eremosparton songoricum and Calligonum mongolicum were used as research objects.Sampling points were set up by extending outward at 20(A),60(B),100(C),and 140 cm(D) with the shrub root as the center,each sampling point was sampled at three soil depths(0<h≤5 cm,5 cm<h≤10 cm,10 cm<h≤20 cm,and the soil nutrient content and enrichment at different spatial locations were analyzed respectively.The results indicated that:(1)Both E.songoricum and C.mongolicum had a “fertilizer island” effect,and there were significant differences in soil nutrient content among different species and spatial locations(P<0.05).The variation trend of the two plant soil nutrients in different spatial distributions was the same,that was,in the horizontal direction,they gradually decreased as the distance from the center of the shrub increased.Among them,the soil SOM,AK,and TN contents of E.songoricum at location D were decreased by an average of 58.16%,52.94%,and 68.18% compared to A,respectively.The content of SOM,AK,TN,and EC in the soil at location D were decreased by an average of 61.38%,13.33%,69.23%,and 21.81%,respectively,compared to location A.In the vertical direction,the content of SOM,AK,and TN in the soil of the two types of plants showed the highest nutrient content in the surface soil,and showed a decreasing trend with the increase of soil depth.The content of AK,pH,and N-NO3- in the rhizosphere soil of C.mongolicum was significantly higher than that of E.songoricum(P<0.05).(2)The enrichment rates of SOM,AK,TN,and total phosphorus(TP) in the soil of the two shrubs showed consistent trends,that was,the enrichment rate of soil nutrients gradually decreased with the increase of soil depth,and the enrichment rate of soil nutrients gradually decreased with the increase of shrub center.(3)There was a significant correlation(P<0.05) between soil enrichment rates at different spatial locations and plant height and crown width.The plant height and crown width of E.songoricum and C.mongolicum showed a significant positive correlation with soil SOM,TN,N-NO3- enrichment rates.In general,both plants showed a “fertilizer island effect”,with obvious spatial heterogeneity in different spatial distributions,different plants had different enrichment capacities for soil nutrients,and their “fertilizer island” effects were also different,with obvious species effects.

     

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