1.Changwang School of Honors, Nanjing University of Information Science and Technology;2.College of Applied Meteorology, Nanjing University of Information Science and Technology
摘 要：为明确不同数量外源磷添加对稻田磷生物有效性组分的影响，以江西鹰潭孙家小流域内新稻田(NP, 2 ~ 3 a)、中期稻田(MP, 20 ~ 30 a)和老稻田(OP, 400 ~ 500 a)为研究对象，基于不同浓度外源磷[0 (CK)、125 (P1)、250 (P2)、500 (P3)、625 (P4)、750 (P5) mg·kg-1（以P计）]添加的淹水培养实验(0 ~ 80 d)，采用模拟生物活化的磷素分级方法(BBP法)，分析了淹水条件下外源磷添加后稻田BBP组分磷的增量(?)动态变化，探讨了各组分磷增量的相关关系及影响因素。结果表明：淹水条件下，稻田有效磷(Bray-P)及BBP组分磷增量随磷添加量的增加而显著增加。BBP组分磷增量大小依次为：氯化钙磷增量(?Ca-P) < 酶提取磷增量(?En-P) < 柠檬酸磷增量(?Ci-P) < 盐酸磷(?HC-P)。培养15 d时，新稻田?Ca-P 与?Ci-P达到最大值；培养60 d时，中期稻田?Ca-P 、?En-P 、?HC-P 及?Bray-P达到最大值；而老稻田中各组分磷随时间变化不明显。通径分析表明：外源添加磷对新稻田和老稻田?Bray-P有显著直接正效应。外源磷添加虽能显著增加稻田磷素生物组分有效性，但其增量最大值的出现时段不同，新稻田与中期稻田中生物有效磷增量最大值分别出现在磷添加后的第15 d与60 d，因此，适时适量地施用磷肥对稻田磷素肥力提升与稻田磷素流失风险管控具有重要意义。
Abstract 【Objective】Phosphorus is an essential nutrient element that affects crop growth, yield enhancement and quality improvement. Due to the application of a large amount of phosphate fertilizer and the lack of scientific management, the utilization rate of phosphate fertilizer is low and the environmental risk increases. Thus, it is important to know the effects of different amounts of exogenous phosphorus (P) addition on P bioavailability components in paddy soil under flooding conditions.【 Method】Three soil samples were collected from the new paddy field (NP, 2-3 years), medium-term paddy field (MP, 20-30 years) and old paddy field (OP, 400-500 years) in Sunjia small watershed of Yingtan, Jiangxi Province. Based on the flooding culture experiment (0-80 days) with different concentrations of exogenous P addition [0 (CK), 125 (P1), 250 (P2), 500 (P3), 625 (P4), 750 (P5) mg·kg-1], the test for simulating the bioactivation process of biologically based P (BBP method) was adopted. The dynamic changes in the increment (?) of soluble P (Ca-P), easily activated and released P (Ci-P), easily mineralizable acid phosphatase (En-P), and the potential inorganic P (HC-P) were analyzed, and the correlation between all P components and influencing factors were evaluated.【 Result】The results showed that under flooding conditions, exogenous P addition could significantly increase the available P (Bray-P) and BBP components such as Ca-P, En-P, Ci-P and HC-P in paddy soil, and the increment of P contents of each component increased significantly with an extension of P addition. The increment of BBP components was changed by the order: ?Ca-P < ?En-P < ?Ci-P < ?HC-P. On day 15 of incubation, the ?Ca-P and ?Ci-P in the new paddy field reached a maximum value while on day 60, the ?Ca-P, ?En-P, ?HC-P and ?Bray-P in the medium-term paddy field reached their maximum value. However, the P content of each component did not change significantly in the old paddy field. The ratio of ΔBray-P to ΔTP (ΔBray-P/ΔTP) in paddy soil after exogenous P addition showed the same trend as that of ΔBray-P, but there was no significant difference among different P additions. Path analysis showed that exogenous P addition had a significant direct positive effect on ?Bray-P in new and old paddy soil; ?Ci-P had a significant direct positive effect on ?Bray-P in new paddy field; ?HC-P and ?Ca-P had a significant direct positive effect on ?Bray-P in medium-term paddy field, and ?En-P had a significant direct positive effect on ?Bray-P in old paddy field.【Conclusion】Although exogenous P addition can significantly increase the components of the bioavailability of P in paddy soil, the emergence stage of the maximum increment bioavailability of P in paddy soil is different. Therefore, it is of great significance to timely and appropriately apply P fertilizers for the improvement of P fertility and the risk control of P loss in paddy fields.
cao hua, li huan, fan hui lin, niu ben, wang yan ling. Exogenous Phosphorus Addition Can Increase Phosphorus Bioavailability in Paddy Soil of Different Cultivated Years[J]. Acta Pedologica Sinica,,[In Press]