周年轮作休耕模式对土壤球囊霉素和团聚体稳定性的影响

Effect of annual rotation and fallow pattern on the soil glomalin and aggregate stability

为探究周年轮作休耕模式对土壤球囊霉素和团聚体稳定性的影响规律与机制,通过田间试验设置苕子-玉米轮作、豌豆-玉米轮作、休闲-玉米和全年休闲4个处理,分析不同种植模式下团聚体、球囊霉素相关土壤蛋白(GRSP)及有机碳(SOC)的变化规律。结果表明:与休闲-玉米、苕子-玉米轮作、豌豆-玉米轮作相比,全年休闲能显著增加大团聚体(>0.25 mm)含量,提高团聚体稳定性;在不同团聚体粒级下,与休闲-玉米相比,苕子-玉米轮作、豌豆-玉米轮作和全年休闲均能有效增加GRSP和SOC的含量,且全年休闲效果更佳;结构方程模型的结果显示,GRSP对SOC和可溶性有机碳(DOC)有直接的正面影响,对团聚体稳定性有间接影响,各因子对平均质量直径的总效应由大到小依次为WSA_(>0.25)(>0.25 mm水稳性团聚体)>DOC>总GRSP>SOC>易提取GRSP;相关性分析表明,不同团聚体粒级下GRSP与SOC均呈线性正相关关系,但在不同粒级下的相关系数的大小有所差异。研究表明,合理的轮作休耕模式有助于恢复地力,改善耕地质量,减少水土流失。

Unreasonable land use methods severely affect soil erosion on sloping farmland. The central government has proposed to promote a pilot farmland crop rotation and fallow system. To explore the influence of annual rotation and fallow patterns on the glomalin-related soil protein and aggregate stability, this study set up four treatments:vetch-maize rotation, pea-maize rotation, fallow-maize, and year-round fallow through field experiments. Subsequent changes to soil aggregate, glomalin-related soil protein(GRSP), and organic carbon(SOC)under these different planting patterns were analyzed. The results showed that the large aggregates(>0.25 mm)content and aggregate stability in the annual fallow treatment were higher than those in other treatments. The GRSP and SOC content in vetch-maize rotation,pea-maize rotation, and year-round fallow treatment were higher than those in fallow-maize treatment;in particular, those in the yearround fallow treatment were highest. The structural equation model analysis indicated that GRSP had a direct positive effect on SOC and DOC, and an indirect effect on aggregate stability. The effect of each factor on MWD was in the order:WSA_(>0.25)(>0.25 mm water stable aggregate)>DOC>total GRSP>SOC>easily-extractable GRSP. Correlation analysis showed that GRSP was linearly positively correlated with SOC in different aggregate sizes, but the correlation coefficients were different in different sizes. In summary, a reasonable crop rotation and fallow pattern can help restore soil fertility, improve the quality of cultivated land, and reduce soil erosion.