单点源入渗条件下肥液入渗水磷分布与数值模拟

【目的】 研究不同滴头流量在滴灌条件下对风沙土中水磷分布的影响。【方法】 采用室内试验,研究相同灌水量不同滴头流量(0.3、0.9、1.2 L/h)单点源入渗条件下的土壤水分和有效磷在土壤中的分布情况,进行数值模拟研究。【结果】 滴头流量为0.3 L/h时,土壤湿润范围由0~15 cm深度向30~45 cm深度逐渐缩小,土壤中有效磷分布较均匀。滴头流量为0.9 L/h时,各深度土层土壤湿润范围一致,滴头下方15~30 cm深度土壤有效磷浓度峰值为800 mg/kg,高于滴头流量为0.3 L/h时。且有效磷含量水平方向上分布范围较1.2 L/h流量时广。在相同的滴头流量下,磷肥随着水分入渗向下迁移,有效磷含量主要聚集在15~30 cm深度内;随着滴头流量增大,磷肥向土壤深层迁移量增大。【结论】 在灌水量为225 m³/hm²、磷酸二氢铵施入量为300 kg/hm²时,土壤中有效磷浓度较高。在不同滴头流量条件下,土壤有效磷分布符合滴头正下方浓度较高,随水扩散后含量逐渐降低的规律。

Study on the Redistribution and Numerical Simulation of Phosphorus in the Infiltration Water of Fertilizer Solution under the Condition of Single Point Source Infiltration

【Objective】 To Study of different emitter flow rates on the distribution of water and phosphorus in aeolian sandy soil under drip irrigation.【Methods】 In this project, the distribution of soil water and available phosphorus in soil under the condition of single point source infiltration with the same irrigation amount and different emitter flow rates (0.3 L/h, 0.9 L/h, 1.2 L/h) was studied by laboratory experiment, and the numerical simulation was conducted.【Results】 When the drop flow was 0.3 L/h, the soil moisture range gradually decreased from 0-15 cm to 30-45 cm, and the distribution of available phosphorus in soil was more uniform. When the flow of the drop head was 0.9 L/h, the soil moisture range of each depth soil layer was the same, and the peak value of the soil effective phosphorus concentration in the depth of 15-30 cm under the drop head is 800 mg/kg, which was higher than that of the drop head flow of 0.3 L/h. The distribution range of available phosphorus content in horizontal direction was wider than that of 1.2 L/h flow. The results showed that the effective phosphorus content was mainly concentrated in the depth of 15-30 cm with the infiltration of water; with the increase of the drop flow, the amount of phosphorus fertilizer to the deep layer of soil increased.【Conclusion】 When irrigation amount is 225 m³/hm² and ammonium dihydrogen phosphate application amount was 300 kg/hm², available phosphorus concentration in soil was higher. Under the condition of different emitter discharge, the distribution of soil available phosphorus is in line with the law, that is, the concentration of soil available phosphorus is higher directly below the emitter and gradually decreased with the water diffusion.