黄土丘陵区典型小流域不同植被恢复方式土壤理化性质差异及其影响因素

Differences in soil physicochemical properties and influencing factors under different vegetation restoration methods in typical small watersheds in Loess hilly areas

黄土高原不同小流域由于环境特点和植被恢复方式的不同,导致其生态效益存在地带性差异。为了研究不同环境和植被恢复方式下土壤理化性质的差异性及影响机制,选取黄土高原两个小流域不同植被恢复方式(油松人工林、侧柏人工林和自然恢复对照)作为研究对象,对比分析植被恢复方式和环境特点对土壤养分储量和水分状况,以及植被生长状态等生态恢复效益的影响和贡献。结果表明:(1)吉县自然恢复下全氮含量最高,均值为0.79g/kg;有机碳均值含量表现为定西油松最高,吉县对照次之,其均值分别是16.91g/kg,13.46g/kg;全磷含量和全钾含量最高的是吉县油松样地和定西的侧柏样地,其均值为2.40g/kg和23.43g/kg。(2)土壤速效氮、速效磷、速效钾的含量,吉县的油松样地、侧柏样地和自然对照样地分别高于定西2.89%,81.03%和7.49%。(3)基于主成分分析(PCA)和方差分解(VP)结果,在不同小流域影响土壤养分和水分含量的主要因素有所差异。其中吉县和定西小流域影响土壤养分的主要因素分别为土壤物理性质和植被属性,解释度分别为79.92%、55.3%;而土壤含水量主要受降水量和土壤-植被共同影响,其解释度分别为87.06%、43.53%。综上结果表明,多雨条件的吉县地区植被适合自然恢复,而相对干旱的定西地区植被则适合人工恢复。考虑黄土高原植被恢复的人工和自然恢复方式,结果证明不同小流域的降水量与土壤含水量等环境特点影响植被生长状态和植被恢复的生态效益,可为因地制宜的科学植被恢复策略提供数据和理论支持。

Due to differences in environmental characteristics and vegetation restoration methods,there are regional differences in the ecological benefits of different small watersheds on the Loess Plateau.In order to study the differences and influencing mechanisms of soil physicochemical properties under different environments and vegetation restoration methods,this study selected two small watersheds on the Loess Plateau with different vegetation restoration methods(Pinus tabulaeformis artificial forest,Platycladus orientalis artificial forest,and natural restoration control)as the research objects,and compared and analyzed the impact and contribution of vegetation restoration methods and environmental characteristics on soil nutrient storage,soil moisture status,as well as vegetation growth status and other ecological restoration benefits.The results showed that:(1)Under natural restoration in Jixian County,the total nitrogen content was the highest,with an average of 0.79 g/kg;The average organic carbon content of Pinus tabulaeformis in Dingxi was the highest,followed by the control in Jixian,with an average of 16.91 g/kg and 13.46/kg,respectively;The highest total phosphorus and potassium contents were found in the Pinus tabulaeformis sample plots in Jixian County and Platycladus orientalis sample plots in Dingxi,with an average of 2.40 g/kg and 23.43 g/kg,respectively.(2)The contents of soil available nitrogen,available phosphorus,and available potassium in the Pinus tabulaeformis,Platycladus orientalis,and natural control plots in Jixian were 2.89%,81.03%,and 7.49% higher than those in Dingxi,respectively.(3)Based on the results of Principal Component Analysis(PCA)and Decomposition of Variance(VP),the main factors affecting soil nutrients and water content varied in different small watersheds.The main factors affecting soil nutrients in Jixian and Dingxi small watersheds were soil physical properties and vegetation attributes,with explanatory degrees of 79.92% and 55.3%,respectively;The main factors affecting soil moisture content were rainfall and soil vegetation,with explanations of 87.06% and 43.53%,respectively.The above results indicate that the vegetation in Jixian area,which is prone to rainfall,is suitable for natural restoration,while the vegetation in Dingxi area,which is relatively arid,is suitable for artificial restoration.This study considers artificial and natural restoration methods for vegetation restoration on the Loess Plateau.The results demonstrate that the environmental characteristics such as rainfall and water content in different regions affect vegetation growth status and ecological benefits of vegetation restoration.This can provide data and theoretical support for scientific vegetation restoration strategies tailored to local conditions.