有机肥配施对中国农田土壤容重影响的整合分析

有机肥配施是我国化肥减施的重要手段之一，探究化学氮肥减施并配施有机肥对不同土壤利用类型、土壤质地及有机肥类型下土壤容重的影响程度，对于深刻认识农田土壤物理状况具有重要意义。本研究通过整合2000年1月1日至2020年5月31日期间已公开发表的文献数据，建立了包含320组相对独立数据的数据库。利用Meta-analysis定量分析不同土壤利用类型、土壤质地、有机肥类型、有机肥施用量、施用频次和施用年限等分类条件下化学氮肥减施并配施有机肥对土壤容重的影响。结果表明，与常规化学氮肥施用相比，配施有机肥显著降低了土壤容重，平均降幅为4.53%。不同土壤利用类型下，有机肥配施显著降低了果园土壤容重，降幅为9.06%，显著高于水田（3.72%）和旱地（5.25%）土壤容重的降幅。不同土壤质地下，有机肥配施使砂土土壤容重下降6.96%，显著高于壤土和黏土容重的降幅。不同有机肥类型之间，生物肥料对土壤容重的影响最大，土壤容重降幅为5.70%，生物炭的影响次之，其土壤容重的降幅为5.21%，二者对土壤容重的影响显著大于动物粪肥和作物秸秆（土壤容重降幅分别为3.67%和2.30%）。此外，土壤容重的下降幅度随有机肥施用量和施用年限、施用频次的增加而呈现增大趋势。本研究为评估我国化学氮肥减施对土壤容重的影响提供了数据基础。

Meta-analysis on the responses of soil bulk density to supplementation of organic fertilizers in croplands in China

The combined application of organic fertilizers is one of the important methods of chemical fertilizer reduction in China. It is of great significance to identify the responses of soil bulk density to chemical nitrogen fertilizer reduction and the supplementation of organic fertilizers under different soil utilization types, soil texture, and organic fertilizer types to explore the soil physical condition of farmland. In this study, a database containing 320 pairs of data was established by integrating data from published literature. Meta-analysis was applied to quantify the effects of chemical nitrogen fertilizer reduction and supplementation of organic fertilizers on soil bulk density under different soil utilization types, soil texture, organic fertilizer types, amount of organic fertilizer application, organic fertilizer application frequency, and experimental duration. Results showed that chemical nitrogen fertilizer reduction and supplementation of organic fertilizers significantly decreased the soil bulk density by 4.53%, compared with conventional fertilization. As for soil utilization types, chemical nitrogen fertilizer reduction and the supplementation of organic fertilizers significantly(P<0.05) decreased the soil bulk density of garden fields by 9.06%, which was significantly higher than that of paddy fields(3.72%) and upland(5.25%) soils. When grouped by soil textures, the decreased rate of the application of organic fertilizers on soil bulk density of sandy soil(6.96%) was significantly higher than that for loam and clay soil. There were different results under various organic fertilizer types. The combination of bio-organic fertilizers reduced soil bulk density by 5.70%, followed by biochar with a reduction rate of 5.21%, which were significantly higher than that of animal manure and crop straw(3.67% and 2.30%, respectively). In addition, the decrease in soil bulk density showed an upward trend with the increase in the amount of organic fertilizer, the experimental duration, and application frequency. This study provides a data foundation for assessing the impact of chemical nitrogen fertilizer reduction on soil bulk density in China.