Purpose

Organic mulching is an effective forest management technique that improves the soil environment and promotes plant growth. The rhizosphere is an important interface connecting root systems and soil. However, the rhizosphere effects (REs) after organic mulching are still unknown.

Methods

We conducted a field experiment in a 15-year-old Ligustrum lucidum forest of urban greening space. Changes in REs on carbon and nitrogen fractions, enzyme activity after organic mulching were measured, and their relationships with fine-root traits and soil properties were analysed.

Results

Organic mulching reduced or inverted REs for most enzyme activities and carbon and nitrogen fractions but only significantly decreased the positive REs for urease activities and weakened the negative REs for peroxidase activities. Furthermore, more enzymes were affected over time, and more organic mulch application had greater effects. Seasons affected REs more than organic mulching; seasons contributed more to changes in fine-root traits and soil properties. REs on biotic factors (microbial biomass carbon, microbial biomass nitrogen, urease, and peroxidase activities), which are more sensitive than other soil carbon and nitrogen fractions we measured, were primarily related to fine-root traits (specific root length, specific surface area, and carbon and nitrogen content) and soil properties (temperature, water content, and bulk density).

Conclusion

Organic mulching masks the REs on most soil carbon and nitrogen fractions, as well as on enzyme activities, and the REs on enzyme activities are more sensitive. Understanding the variation in REs will improve our knowledge of element cycling between soil and plants.

中文翻译：

---

有机覆盖物掩盖了根际对城市绿化空间中碳氮含量和酶活性的影响

目的

有机覆盖是一种有效的森林管理技术，可以改善土壤环境并促进植物生长。根际是连接根系和土壤的重要界面。但是，有机覆盖后的根际效应（REs）仍然未知。

方法

我们在具有15年历史的城市绿化女贞子森林中进行了野外试验。测定了有机覆盖后稀土元素碳，氮含量，酶活性的变化，并分析了它们与细根性状和土壤特性的关系。

结果

有机覆盖减少或反转了大多数酶活性以及碳和氮组分的RE，但仅显着降低了脲酶活性的正RE，减弱了过氧化物酶活性的负RE。此外，随着时间的推移，更多的酶受到影响，更多的有机覆盖物施用具有更大的影响。季节对可再生能源的影响大于有机覆盖。季节对细根性状和土壤特性的变化贡献更大。生物因子（微生物生物量碳，微生物生物量氮，脲酶和过氧化物酶活性）的可再生能源比我们测量的其他土壤碳和氮组分更敏感，主要与细根性状（比根长，比表面积）相关，碳和氮含量）和土壤特性（温度，水含量和堆积密度）。

结论

有机覆盖物掩盖了大多数土壤碳和氮组分以及酶活性上的RE，而RE对酶活性的敏感性更高。了解稀土元素的变化将提高我们对土壤与植物之间元素循环的了解。