不同垦殖方式下果园土壤有机碳的空间分布特征

Spatial Distribution of Soil Organic Carbon in Orchards Under Different Reclamation Modes

以福建尤溪玉池果园水土流失定位观测点为平台,研究了不同果园垦殖方式对土壤有机碳分布的影响。结果表明,不同垦殖方式下果园土壤有机碳在小生境分布和坡面再分布两个尺度上呈现出不同的分布特征,水平方向上,清耕果园土壤有机碳含量呈沿树干向外减少的分布规律,而生草果园土壤有机碳含量水平变化不明显;垂直方向上,果园土壤有机碳含量随土层加深而逐渐减少;坡面再分布上,清耕果园表现为下坡位>中坡位>上坡位,生草果园为中坡位>下坡位>上坡位。生草垦殖模式降低了果园土壤有机碳的水平分异,但促进果园土壤有机碳的垂直分异。在以上结果的基础上,提出了小生境混合取样的果园土壤采样方法。

The information on the spatial distribution of soil organic carbon is critical for appropriate measurements of soil productivity,hydrology characteristics and carbon balance.A better understanding of the spatial distribution of soil organic carbon and its impact factors will increase the accuracy for estimating organic carbon storage.Thus three types of orchard soils with different reclamation modes（located at Yuchi village,Fujian Province） were chosen to study the spatial variability of soil organic carbon content.Results showed that there were different distribution characteristics of soil organic carbon in the orchard on microhabitat distribution and redistribution slope.Soil organic carbon contents in the clean-tillage orchard showed less outward along the trunk in the horizontal direction.But there was no significant difference in soil organic carbon along the trunk in the herbage interplanting orchard.Soil organic carbon under different cultivating systems decreased with soil depth in vertical direction.On the slope re-distribution,soil organic carbon content varied greatly with different cultivating methods,for example,the downhill bits middle slope upper slope under clean tillage treatment,the middle slope downhill bit upper slope under herbage interplanting.Herbage interplanting reduced the horizontal heterogeneity of soil organic carbon in orchards,but increased the vertical variation.On the basis of the above results,a mixed sampling method from different niches under canopy of fruit trees was proposed.