Effects of landscaping waste mulching on soil fertility of urban green space

  Objective   This study aimed to explore the impact of landscaping waste mulching on soil fertility of urban green spaces, in order to provide a basis for the resource utilization of landscaping waste to solve urban green space soil problems.

  Method  The Old Summer Palace, a typical urban green space soil in Beijing, was taken as the research object. Through field experiments, four different treatments were set up: no covering (CK), the upper layer was wood chips + the lower layer was landscaping waste compost for 15 d (A), the upper layer was wood chips + the lower layer was landscaping waste compost for 30 d (B), the upper layer was wood chips + the lower layer was landscaping waste compost for 60 d (C), and then analyzed and measured in the laboratory. Combined with the modified Nemerow index method, the comprehensive soil fertility index was calculated. Pearson correlation and stepwise regression analysis were used to analyze the effects of different mulching treatments on soil fertility.

  Result  In 0−10 cm soil layer, the contents of soil available phosphorus and available potassium were significantly increased by C mulching treatment (P < 0.05); in 10−20 cm soil layer, the content of soil available potassium was significantly increased by C mulching treatment (P < 0.05). The comprehensive fertility index of soil showed that the comprehensive fertility of 0−10 cm soil layer was significantly improved by C mulching treatment (P < 0.05). The F_imin value in the modified Nemero index method and stepwise regression analysis showed that the limiting factors of soil comprehensive fertility were soil bulk density and available phosphorus, soil organic matter was the most important factor affecting soil comprehensive fertility, followed by soil available phosphorus and soil bulk density.

  Conclusion   In conclusion, landscaping waste mulching had different degrees of influence on soil physicochemical properties and comprehensive fertility. The results show that treatment C is the best mulching scheme. In the future research, we should pay more attention to the dynamic change and improvement of the main influencing factors of soil fertility (soil organic matter, soil bulk density and available phosphorus).