磷肥在不同磷素水平酸性水稻土中生物有效性研究

Bio-availability of phosphorus fertilizers in acid paddy soils with different P status.

通过盆栽试验研究不同磷水平土壤上施用不同磷肥对黑麦草生长的影响及种植黑麦草后土壤磷组分的变化.结果表明,与不施磷处理相比,施磷后低磷土壤(NK和CK)上黑麦草干物质重和吸磷量的增幅范围分别为32.7%～53.0%和82.4%～151.9%;在高磷土壤(NPK)上其增幅较小,分别为11.0%～14.0%和51.1%～65.0%.相同施肥处理时,3个土壤上黑麦草干物质重和吸磷量的大小顺序均为NPK>NK>CK.施用磷矿粉KPR取得高于或相当于普通过磷酸钙(SSP)的效果.3个土壤经KPR500、KPR1000和SSP22施磷处理后黑麦草的磷肥农学利用率(AEP)平均值分别为5.6、2.5和124.2,磷肥表观回收率(REP)平均值分别为1.0、0.7和21.1.种植黑麦草后,与不施磷处理相比,施磷后土壤Resin-P,NaHCO3-Pi和NaHCO3-Po3个有效磷组分均有不同程度的增加,化学吸附态组分NaOH-Pi含量有所增加,NaOH-Po含量比较稳定;施磷矿粉后土壤HCl-P和Residual-P含量显著增加.

Pot experiments on three acid paddy soils with different P status were conducted to investigate the effects of P fertilizers on ryegrass growth and changes of soil P fractions after ryegrass planting. The results show that application of P fertilizers increased dry matter weight and P uptake of ryegrass on low-P status soils （NK and CK） by 32.7%-53. 0% and 82. 4%-151.9%, respectively; on high-P status soil （NPK） by 11.0%- 14.0% and 51.1%-65.0 %, respectively. Dry matter weight and P uptake of ryegrass on NPK soil were higher than that on NK and CK soil under the same fertilizer treatment. Average agronomic efficiency of P fertilizer （AEP） for KPR500, KPR1000 and SSP22 on three soils were 5.6, 2. 5 and 124.2, respectively; average recovery efficiency of P fertilizer （REP） for KPR500, KPR1000 and SSP22 on three soils were 1.0, 0. 7 and 21.1, respectively. Compared with the control （no P application）, soil available P （Resin-P, NaHCO3-Pi and NaHCOs-Po） increased at different grade on the three soils after P fertilizers application. Soil NaOH-Pi also increased, while soil NaOH-Po was stable and less affected by addition of P fertilizers. Phosphate rock application increased soil HCl-P and Residual-P fractions substantially.