添加木本泥炭和膨润土对侵蚀退化黑土理化性质的影响

Effects of Adding Woody Peat and Bentonite on Physical and Chemical Properties of Eroded and Degraded Black Soil

为减缓黑土农田侵蚀退化,提高农田地力。本研究选取典型侵蚀退化黑土地,向土壤中添加木本泥炭和膨润土,利用室内模拟和田间原位观测相结合,进行土壤饱和导水率、导气率和相对气体扩散率以及持水性、有机碳含量和作物产量研究。结果显示:室内条件下添加2%或4%木本泥炭会使饱和导水率分别降低14.3%和增加9.9%、导气率分别增加18.9%和4.1%、相对气体扩散率分别增加15.5%和6.6%、有机碳含量分别增加39.4%和71.5%、盆栽玉米产量分别增加2.0倍和1.9倍;添加1%膨润土会使饱和导水率、导气率和相对气体扩散率分别降低63.2%、55.3%和7.6%,有机碳含量和盆栽玉米产量分别增加1.0%和1.1倍;添加2%或4%木本泥炭和1%膨润土会使饱和导水率分别降低65.8%和73.1%、导气率分别降低33.2%和32.8%、相对气体扩散率分别增加0.2%和降低4.7%、有机碳含量分别增加37.8%和70.6%、盆栽玉米产量分别增加1.9倍和1.5倍。大田中添加木本泥炭会使土壤饱和导水率、相对气体扩散率、有机碳含量和大豆产量分别增加75.0%、32.0%、36.1%和43.2%,土壤导气率降低45.2%;添加膨润土会使土壤饱和导水率、导气率和相对气体扩散率分别降低39.1%、44.4%和44.0%,有机碳含量和大豆产量分别提高3.6%和4.2%,但有机碳含量和大豆产量差异不显著。混合添加木本泥炭和膨润土会使土壤饱和导水率、相对气体扩散率、有机碳含量和大豆产量分别增加134.4%、28.0%、36.0%和26.3%,土壤导气率降低38.2%。添加木本泥炭和膨润土均可提高土壤持水能力,添加膨润土的处理有机碳分解减慢。总之,混合添加效果最好,可提高土壤通气透水性、持水能力、有机碳含量和作物产量,并有助于有机碳累积。

【Objective】Black land is a valuable land resource,which plays an important role in ensuring food security in the northeast region of China.In order to slow down the erosion and degradation of black soil farmland and improve farmland fertility,new soil management practices need to be developed.【Method】In this study,woody peat and bentonite were added to a typical eroded and degraded black land.The saturated hydraulic conductivity,air permeability and relative gas diffusion,water holding capacity,organic carbon content and crop yield were evaluated by the combination of indoor simulation and field in-situ observation.【Result】The results showed that:under indoor conditions,(1)adding 2%or 4%woody peat decreased the saturated hydraulic conductivity by 14.3%or increased it by 9.9%,increased the air permeability by 18.9%or 4.1%,increased the relative gas diffusion by 15.5%or 6.6%,increased the organic carbon content by 39.4%or 71.5%,and increased the yield of potted maize by 2.0 times or 1.9 times respectively;(2)adding 1%bentonite decreased the saturated hydraulic conductivity,air permeability and relative gas diffusion by 63.2%,55.3%and 7.6%,and increased the organic carbon content and yield of potted maize by 1.0%and 1.1 times,respectively;(3)adding 2%or 4%woody peat and 1%bentonite decreased the saturated hydraulic conductivity by 65.8%or 73.1%,decreased the air permeability by 33.2%or 32.8%,increased the relative gas diffusion by 0.2%or 4.7%,increased the organic carbon content by 37.8%or 70.6%,and increased the yield of potted maize by 1.9 times or 1.5 times.The saturated hydraulic conductivity,relative gas diffusion,organic carbon content and soybean yield increased by 75.0%,32.0%,36.1%and 43.2%respectively,and the air permeability decreased by 45.2%when woody peat was added to the eroded farmland.Also,the saturated hydraulic conductivity,air permeability and relative gas diffusion decreased by 39.1%,44.4%and 44.0%respectively,while the organic carbon content and soybean yield increased by 3.6%and 4.2%,respectively,when bentonite was added to the eroded farmland.Even though there was no significant difference in organic carbon content and soybean yield;the soil saturated hydraulic conductivity,relative gas diffusion,organic carbon content and soybean yield increased by 134.4%,28.0%,36.0%and 26.3%respectively,and the air permeability decreased by 38.2%when woody peat and bentonite was added to the eroded farmland.The addition of woody peat and bentonite could improve the water holding capacity of black land soils,and bentonite can retard the decomposition of organic carbon.【Conclusion】In general,the mixed addition of woody peat and bentonite has the best effect,which can effectively improve the soil aeration permeability,water holding capacity,organic carbon content and crop yield,and also help to accumulate organic carbon in the soil.It is an effective measure to rapidly improve the degraded black soil.