黑土肥料长期定位试验冻土分割搬迁后土壤融合效果评价

为了明确黑土长期定位试验土壤搬迁后与新址的融合效果,以一个搬迁土块为研究对象,明确搬迁土块间的接缝处土壤与距接缝处不同距离的中心土壤在理化特性上的不同。结果表明,0~20 cm层次土体中心50 cm处的田间持水量比接缝处高5%,容重低4%,变异系数均明显高于其他层次;20~40 cm层次,土壤的固相率和容重高于其他层次,田间持水量降低,土块横切面各部位物理性质均无明显差别;剖面底部80~100 cm层次接缝处土壤松散缝处的固相率比30 cm和土体中心处低4.3%,液相率低3.1%,气相率高出7.6%,容重下降8.3%。0~40 cm土层的缝处、距缝30 cm和距缝50 cm处的孔隙率均低于40~100 cm层次,其中80~100 cm层次的孔隙率最大,20~40cm孔隙率最低为44.2%;土壤饱和导水率0~20 cm层次为35.3~38.0 cm/d,随着深度的加深呈下降趋势,均小于20cm/d;而80~100 cm层次缝处的饱和导水率值高达144.4 cm/d,是表层土壤的4倍。同一层次搬迁土块缝处与土块中心土壤速效养分无明显差别,缝处全氮含量均高于土块的其他位置,且与距缝30 cm和50 cm处的数值差异均达到显著水平(P0.05);pH随着土层的加深逐渐增大,碱解氮和土壤有机碳含量随着土层的加深而下降。长期定位土壤搬迁5 a后,深层土壤接缝处还处于疏松状态,下层土壤的融合要弱于上层土壤。

Assessment on Soil Fusion Effects of Segmented and Removed Frozen Black Soil Under Long-term Located Experiment

In order to evaluate the merge effect after and before soil being moving from long-term located experiment, one moved soil column was chosen to study the difference of soil chemical and physical properties between then center of soil column and joints. The result showed that: the field capacity inthe center of soil columnin the layers of 0~20cmwas increased by 5%, compared with joints, and bulk density was decreased by 4%, with higher the variation coefficient. There was no significant difference between soil joints and the center in 20~40cm layers, only showing that the soil solid rate and bulk density was increased and field capacity was reduced.In 80~100cm soil layer, the solid rate of soil column joint were decreased by 4.3%, the gas rate was increased by 7.6%, bulk density was reduced by 8.3%, compared with soil column center. The porosity in 0~40 cm soil layer was lower than 40~100 cm layers, with maximum in 80~100 cm andminimum in 20~40 cm. Soil saturated hydraulic conductivity was decreased with the depth increasing, was35.3~38.0 cm/d in 0~20 cm soil layer, but soil saturated hydraulic conductivity in soil column jointin 80~100 cm soil layer was 4 times higher than soil surface. The available nutrients contents of same soil layers had no significant differences between soil columnjoints and centers. A significant difference of total nitrogen between soil column joints and other positions was observed.The pH was gradually increasing with the soil depths increasing, but available nitrogen and soil organic carbon were reduced. After 5 years of soil being moved, without human interrupt in deeper soil, the juncture place in the deep place was still in the loose state, indicating that it needs a long time to merge after new soil column was inserted into.