Song Ke, Sun Lijuan, Lv Weiguang, Zheng Xianqing, Sun Yafei, Terzaghi William, Qin Qin, Xue Yong
Institute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai, China.
Department of Biology, Wilkes University, Wilkes-Barre, PA, USA.
PeerJ. 2020 Sep 17;8:e9870. doi: 10.7717/peerj.9870. eCollection 2020.
To promote straw degradation, we inoculated returned farmland straw with earthworms (). Increasing the number of earthworms may generally alter soil organic carbon (SOC) dynamics and the biological activity of agricultural soils.
We performed soil mesocosm experiments with and without earthworms to assess the decomposition and microbial mineralization of returned straw and soil enzyme activity across different time periods.
When earthworms were present in soil, the surface residues were completely consumed during the first four weeks, but when earthworms were absent, most of the residues remained on the soil surface after 18 weeks. On day 28, the SOC content was significantly higher in the treatment where both earthworms and residue had been added. The SOC content was lower in the treatment where earthworms but no residue had been added. The organic carbon content in water-stable macroaggregates showed the same trend. During the first 14 weeks, the soil basal respiration was highest in the treatments with both residues and earthworms. From weeks 14 to 18, basal respiration was highest in the treatments with residues but without earthworms. We found a significant positive correlation between soil basal respiration and soil dissolved organic carbon content. Earthworms increased the activity of protease, invertase, urease and alkaline phosphatase enzymes, but decreased β-cellobiohydrolase, β-glucosidase and xylosidase activity, as well as significantly reducing ergosterol content.
The primary decomposition of exogenous rice residues was mainly performed by earthworms. Over a short period of time, they converted plant carbon into soil carbon and increased SOC. The earthworms played a key role in carbon conversion and stabilization. In the absence of exogenous residues, earthworm activity accelerated the decomposition of original organic carbon in the soil, reduced SOC, and promoted carbon mineralization.
为促进秸秆降解，我们用蚯蚓对农田回田秸秆进行了接种（）。增加蚯蚓数量通常可能会改变土壤有机碳（SOC）动态和农业土壤的生物活性。
我们进行了有蚯蚓和无蚯蚓的土壤中宇宙实验，以评估不同时间段内回田秸秆的分解和微生物矿化以及土壤酶活性。
当土壤中有蚯蚓时，表层残留物在最初四周内被完全消耗，但当没有蚯蚓时，18周后大部分残留物仍留在土壤表面。在第28天，添加了蚯蚓和残留物的处理中SOC含量显著更高。添加了蚯蚓但没有残留物的处理中SOC含量较低。水稳性大团聚体中的有机碳含量呈现相同趋势。在最初14周内，同时添加残留物和蚯蚓的处理中土壤基础呼吸最高。从第14周到18周，有残留物但没有蚯蚓的处理中基础呼吸最高。我们发现土壤基础呼吸与土壤溶解有机碳含量之间存在显著正相关。蚯蚓增加了蛋白酶、转化酶、脲酶和碱性磷酸酶的活性，但降低了β - 纤维二糖水解酶、β - 葡萄糖苷酶和木糖苷酶的活性，同时显著降低了麦角固醇含量。
外源水稻残留物的初级分解主要由蚯蚓进行。在短时间内，它们将植物碳转化为土壤碳并增加了SOC。蚯蚓在碳转化和稳定中起关键作用。在没有外源残留物的情况下，蚯蚓活动加速了土壤中原有有机碳的分解，降低了SOC并促进了碳矿化。
