水蚀风蚀交错区林分类型对土壤碳氮磷及生态化学计量特征的影响OA

To elucidate the carbon,nitrogen,and phosphorus contents and their ecological stoichiometric characteristics in the soil of the loess-humid transition zone in northern Shaanxi,this study selected four typical artificial forests—Platycladus orientalis,Pinus tabuliformis,Populus simonii,and Pinus sylves-tris var.mongolica—to analyze the vertical distribution of soil carbon,nitrogen,phosphorus,and their stoi-chiometric ratios(C/N,C/P,N/P)in the 0-10,10-20,20-40 cm soil layer using stratified soil sam-pling.The results showed that 1)SOC,TN,C/N,and C/P were significantly influenced by both forest type and soil depth(P＜0.05),while TP showed no significant interaction with soil depth and forest type(P＞0.05).Except for TP content,the other indicators in the Pinus sylvestris var.mongolica forest showed a variation characteristic of 20-40 cm＜0-10 cm,while the other three forest types did not show a clear consistent variation pattern;2)The CV values of SOC,TN,C/P,and N/P in the 0-40 cm soil layer of the four types of forest stands were all greater than 36%,indicating significant strong variations.C/N showed moderate variation,and TP showed weak variation;3)Redundancy analysis indicated that the contribution rates of TP(P=0.002),TN(P=0.002),and C/P(P=0.004)were the highest,respectively explaining 56.9%,23.8%,and 14.4%of the variation;4)Correlation analysis indicated that the strongest correlation was observed between SOC and C/P(r=0.985),and SOC and TN showed a highly significant positive correlation(P＜0.01).Additionally,SOC and TN were significantly positively correlated with C/N,C/P,and N/P(P＜0.01).Overall,the study revealed that broadleaf forests exhibited superior soil nutrient ac-cumulation and ecological stoichiometric characteristics compared to needleleaf forests,with phosphorus being a key limiting factor in forest productivity.Nitrogen played a dominant role in the nutrient and stoi-chiometric dynamics of different forest types.Mixed forest systems showed potential for improving soil nu-trient status,and the introduction of broadleaf species could help optimize nutrient limitations,thereby en-hancing the quality of forest stands and ecosystem services in the loess-humid transition zone.