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随着磷肥施用量增加,土壤磷素累积,由此所引起的土壤磷素流失越来越成为水体磷素的重要来源。本研究采集湖北省主要类型土壤,土壤风干过2 mm筛后,加入不同量的K2HPO4(0,30,40,60,100,160,200,240,300,400 mg P/kg土)进行室内培养,测定土壤M-3P、CaCl2-P和Fe、Al含量,计算土壤磷吸持饱和度(DPS),利用Split-line模型,预测不同土壤类型磷素流失风险。结果表明:土壤M-3P与Fe、Al含量间关系符合y=y0+axb方程(P<0.05);土壤DPS与CaCl2-P含量关系,存在一个明显的突变点,即土壤磷素流失环境临界值,超过该值时,CaCl2-P含量急剧增加,但不同土壤类型其临界值差异较大,潮土、红壤和水稻土土壤磷素流失DPS临界值分别为18.8、12.9和13.3%,相对应的CaCl2-P含量分别为2.21、0.92、0.60 mg kg-1,根据以上临界值判断,红壤、水稻土极易发生流失。从区域角度考虑,土壤磷素流失DPS临界值为18.80%,该值能够给当地农业生产过程中的土壤磷素区域环境管理提供指导。
With the increase of phosphorus application, the accumulation of soil phosphorus, the resulting phosphorus loss from soil is increasingly becoming an important source of phosphorus in water. In this study, the main types of soils in Hubei Province were collected. After the soil was air-dried over 2 mm sieve, K2HPO4 (0,30,40,60,100,160,200,240,300,400 mg P / kg soil) Fe and Al contents were calculated, and the soil phosphorus holding saturation (DPS) was calculated. Using the Split-line model, the risk of phosphorus loss in different soil types was predicted. The results showed that the relationship between soil M-3P and Fe and Al content was in accordance with y = y0 + axb equation (P <0.05). There was a clear point of change in the relationship between soil DPS and CaCl2-P, Value, the content of CaCl2-P increased sharply, but the critical values of soil phosphorus in different soil types differed greatly. The critical value of DPS for soil phosphorus loss was 18.8, 12.9 and 13.3% respectively in shale soil, red soil and paddy soil, corresponding to The content of CaCl2-P was 2.21, 0.92 and 0.60 mg kg-1, respectively. According to the above critical values, the red soil and paddy soil were prone to loss. From a regional perspective, the critical value of DPS for soil phosphorus loss is 18.80%, which can provide guidance for the environmental management of soil phosphorus in the local agricultural production.