川中丘陵区桤木、柏木对紫色土风化与养分特征的影响

Effects of Alder and Cypress on Weathering and Nutrient Characteristics of Purple Soil in Hilly Area of Central Sichuan Province

[目的]研究川中丘陵区桤木、柏木树种对紫色土风化与养分特征的影响,为该区水土流失防治与农业生产提供科学依据。[方法]选择川中丘陵区万安小流域为研究区,以桤木、柏木为研究对象,运用野外调查、剖面挖掘采样等方法,研究桤木、柏木对紫色土剖面风化与养分的影响。[结果]①桤木、柏木下土壤剖面分形维数分别为2.07和2.13,较对照分别提高了6.47%和9.03%,其中柏木对物理风化的提升幅度高于桤木。②桤木、柏木、对照剖面的化学风化程度差异并不显著,桤木、柏木生长对土壤剖面化学风化的影响较小。③桤木、柏木下土壤剖面综合肥力指数较之对照分别提高了14.08%和11.27%,其中桤木的提升效果优于柏木,其对有机质,全N,碱解N,速效K的提升尤为显著。④桤木、柏木根系分布密度与剖面分形维数、综合肥力指数均呈现较强的正相关关系(p<0.05),但与化学风化指数的相关关系并不显著(p>0.05)。[结论]桤木、柏木在提升川中丘陵区紫色土物理风化速率与养分特征方面均发挥了积极的作用。

[Objective]The influence of alder and cypress on the weathering and nutrient characteristics of purple soil profiles in the hilly area of Central Sichuan Province was analyzed,in order to provide a scientific basis for soil erosion control and agricultural production.[Methods]The Wanan basin in the hilly area of Central Sichuan Province was selected as the study area,and alder and cypress were used as the study objects.Field survey and profile excavation were conducted to study the effects of alder and cypress on the weathering and nutrients of purple soil profiles.[Results]①The profile fractal dimension of alder and cypress were 2.07 and 2.13,respectively,which increased by 6.47%and 9.03%,respectively,compared with the control,among which the effect of cypress was better than that of alder.②The differences in chemical weathering between alder,cypress,and control profiles were not significant.Alder and cypress growth has less effect on chemical weathering of the profile.③The integrated fertility index of alder and cypress profile increased by 14.08%and 11.27%,respectively,compared with the control.Alder showed a better enhancement effect than cypress,which was especially obvious in organic matter,total N,alkali-hydrolyzable N,and effective K.④The root distribution density of alder and cypress showed a significant positive correlation(p<0.05)with the profile fractal dimension and the integrated fertility index,however,the correlation with chemical weathering index was not significant(p>0.05).[Conclusion]Alder and cypress significantly promote the physical weathering rate and nutrients characteristics of purple soil in the hilly area of Central Sichuan Province.