一年施与两年连施生物炭对稻田土壤磷素稳定性及有效性的影响

Effects of One-year and Two-year Continuous Application of Biochar on the Stability and Availability of Phosphorus in Paddy Soil

以酸性水稻土为研究对象,通过水稻盆栽试验,分析了在不施加生物炭(CK)、只施加一年生物炭(B1)和连续两年施加生物炭(B2)处理下,不同生育期稻田土壤全磷(TP)、活性磷(P_(SOL)、P_(M3))、中稳态磷(Pi_(OH)、Po_(OH)、P_(HCl))、高稳态磷(P_(CL)、P_(OCL))含量及占比的动态变化差异,讨论了稻田土壤遗存磷指数(LGC)、磷饱和度(DPS)、磷吸附容量(SOR)对生物炭添加施用的响应特征。结果表明,与CK相比,B1处理的土壤活性磷含量在分蘖期显著降低、成熟期显著增加,中稳态磷含量在分蘖期显著增加,高稳态磷含量各时期均无显著变化。B2土壤活性磷含量在抽穗期和成熟期均显著增加,中稳态磷含量在分蘖期和成熟期显著增加,高稳态磷含量无显著变化,但占比在抽穗期与成熟期分别显著降低18.8%和27.8%。B1和B2处理LGC和DPS均显著增加,且B1处理土壤SOR在抽穗期显著增加。因此,生物炭添加显著增加了稻田土壤活性磷和中稳态磷的含量与占比,降低了植物利用率较低的高稳态磷的占比,说明生物炭施加增加了稻田土壤遗存磷和生物有效磷含量。研究结果明确了稻秆生物炭施用后稻田土壤磷的稳定性及有效性的变化特征,为稻田土壤磷素管理提供了合理化建议。

This study examined the influence of biochar application on soil phosphorus dynamics in a typical red paddy soil through a rice pot experiment.The experiment compared three treatments:no biochar application(CK),one-year biochar application(B1),and two-year consecutive biochar application(B2).The concentrations and proportions of total phosphorus(TP),active P(P_(SOL),P_(M3)),moderately stable P(Pi_(OH),Po_(OH),P_(HCl)),and highly stable P(P_(CL),P_(OCL))were analyzed at different rice growth stages.Additionally,the responses of soil legacy P index(LGC),P saturation degree(DPS),and P adsorption capacity(SOR)to biochar addition were investigated.The results reveal that compared to the CK treatment,B1 application significantly reduced active P during the tillering stage but increased it during the maturity stage.Moderately stable P increased significantly during the tillering stage in the B1 treatment.No significant changes were observed in highly stable P for all treatments(P<0.05).In the B2 treatment,active P significantly increased during the heading and maturity stages,while moderately stable P increased during the tillering and maturity stages.The content of highly stable P remained unchanged,but its proportion decreased significantly by 18.8%and 27.8%during the heading and maturity stages,respectively.Both B1 and B2 treatments led to a significant increase in LGC and DPS,and the B1 treatment showed a significant increase in SOR during the heading stage.Overall,the addition of biochar significantly increased the content and proportion of active P and moderately stable P in paddy soil,decreased the proportion of highly stable P with low plant utilization,and enhanced soil legacy P and bioavailable P.These findings provide valuable insights for optimizing P management strategies in paddy fields.