免耕条件下蚯蚓对农田水分及土壤物理性质的影响

Effect of Earthworms on Soil Moisture Changes and Physical Properties in Agricultural Fields Under No-tillage

研究蚯蚓活动对免耕条件下农田土壤含水量、土壤团聚体、土壤容重的影响,揭示蚯蚓种群数量对土壤水分特征和土壤物理性质的影响机制。在免耕条件下,以接种蚯蚓数量为试验变量,设置NT0(对照,0条/m^(2))、NT20(2条/m^(2))、NT_(50)(5条/m^(2))和NT_(100)(11条/m^(2))4个接种水平。结果表明:(1)蚯蚓活动提高了0~100 cm土壤深度土壤含水量(0.32%~20.06%),且土壤含水量受接种蚯蚓数量的影响。(2)蚯蚓活动增加了土壤大团聚体数量和稳定性,增加了土壤0.25~0.5、2~5、>5 mm粒级团聚体百分占比。(3)接种足够数量的蚯蚓会减小表层(0~10 cm)的土壤容重,接种蚯蚓会使犁底层(10~20 cm)的土壤容重增加。(4)土壤含水量与2~5 mm粒级团聚体呈显著负相关(P<0.01),与土壤容重(10~20 cm)呈显著正相关(P<0.05)。研究结果可为关中塿土区寻找适宜的耕作手段和合适的蚯蚓接种数量提供科学依据和技术支持。

The study aims to investigate the effects of earthworm activity on soil moisture content,soil aggregates and soil bulk density in agricultural fields under no-tillage condition,and to reveal the influencing mechanism of earthworm population size on soil moisture changes and physical properties.Under no-tillage condition,four inoculation levels of NT0(control,0 earthworm/m^(2)),NT20(2 earthworms/m^(2)),NT_(50)(5 earthworms/m^(2))and NT_(100)(11 earthworms/m^(2))were set as experimental variables.The results showed that:(1)earthworm activity increased soil moisture content(0.32%-20.06%)at 0-100 cm soil depth,and soil moisture content was influenced by the number of earthworms inoculated;(2)earthworm activity increased the number and stability of soil macroaggregates,increased the percentage of soil agglomerates in the 0.25-0.5,2-5 and>5 mm grain classes;(3)inoculation with sufficient numbers of earthworm reduced soil bulk density in the surface layer(0-10 cm),and inoculation with earthworm increased soil bulk density in the bottom layer of the plough(10-20 cm);(4)soil moisture content was significantly negatively correlated(P<0.01)with 2-5 mm grain-size aggregates and significantly positively correlated(P<0.05)with soil bulk density(10-20 cm).The results of the study could provide a scientific basis and technical support for finding suitable tillage methods and appropriate number of earthworm inoculation in the Guanzhong small mound area.