黄土丘陵区退耕草地土壤稳定入渗率生长季变化

Variation of soil stable infiltration rate in growing season for rehabilitated grassland in loess hilly region

运用双环法,探讨了黄土丘陵区退耕草地土壤稳定入渗率生长季的变化。结果表明:(1)赖草地土壤稳定入渗率在生长季内呈现出"W"型显著的季节变化趋势(P<0.05),紫花苜蓿地土壤稳定入渗率则无显著的生长季变化(P>0.05)。在草地生长季,赖草地土壤稳定入渗率值的变化范围为1.61~4.53 mm·min^(-1),平均值为2.89 mm·min^(-1)。赖草地土壤稳定入渗率最小值出现在抽穗期(1.61 mm·min^(-1)),最大值出现在种子成熟期(4.53 mm·min^(-1))。紫花苜蓿地土壤稳定入渗率值的变化范围为2.12~2.3 mm·min^(-1),平均值为2.23 mm·min^(-1)。紫花苜蓿地土壤稳定入渗率最小值出现在种子成熟初期,在旁枝形成期、开花期和种子成熟末期出现最大值2.3mm·min^(-1)。(2)赖草地与裸地的土壤稳定入渗率具有显著性差异(P<0.05),紫花苜蓿地与裸地则无显著性差异(P>0.05),赖草地的平均土壤稳定入渗率最大(2.89±1.03 mm·min^(-1)),其次是紫花苜蓿地(2.23±0.09 mm·min^(-1));(3)土壤容重、总孔隙度和毛管孔隙度等土壤属性生长季的变化是影响黄土丘陵区退耕草地土壤稳定入渗率生长季变化的主要因素;(4)利用土壤容重、总孔隙度和毛管孔隙度等参数可以很好地模拟黄土丘陵区退耕草地土壤稳定入渗率生长季的变化(R2>0.86,NSE>0.86)。

Using two rings method,the seasonal variation of soil stable infiltration rate in growing season for rehabilitated grassland in loess hilly region was discussed. The results were indicated that：（ 1） The soil stable infiltration rate of Leymus secalinus was presented the significant seasonal change trend as ＂W＂type（ P 0. 05） in the growing season,but the soil stable infiltration rate of alfalfa was presented no obvious seasonal variation（ P 0.05）. During the grass growing season,the change range of soil stable infiltration rate of Leymus secalinus was from1. 61 mm·min（-1）to 4. 53 mm·min（-1）,the average value of was 2. 89 mm·min（-1）. The minimum value of soil stable infiltration rate of Leymus secalinus was appeared in earing stage,the maximum value of 4. 53 mm·min（-1）was appeared in seed maturing stage. The soil stable infiltration rate of alfalfa was from 2. 12 mm·min（-1）to 2. 3mm·min（-1）,the average value was 2. 23 mm·min（-1）. The minimum value of soil stable infiltration rate of alfalfa was appeared in early seeds maturing stage,the maximum value of 2. 3 mm·min（-1）was appeared in side branch forming stage,flowering stage and seeds mature stage.（ 2） The soil stable infiltration rate of Leymus secalinus and bare land was possessed significant difference（ P 0. 05）,but for the alfalfa and bare land was no significant difference（ P 0. 05）. The average soil stable infiltration rate of Leymus secalinus was the maximum（ 2. 89 ± 1. 03mm·min（-1））,the secondly was the alfalfa grassland（ 2. 23 ± 0. 09 mm·min（-1））.（ 3） The variation of soil attributes as soil bulk density,total porosity and capillary porosity etc. were the main factors to influence the change of soil stable infiltration rate in growing season for rehabilitated grassland in losses hilly seasonal region.（ 4） Usingthe parameters of bulk density,total porosity and capillary porosity etc. could be well simulated the change of soil stable infiltration rate in the growing season for rehabilitated grassland in losses hilly region（ R2 0. 86,NSE 0.86）.