沼液对成都平原地区土壤氮、磷、钾含量及其平衡的影响

为探讨在成都平原地区冲积性水稻土上施用沼液后土壤氮磷钾元素含量的变化及养分平衡的状况,实现沼液资源化利用的绿色发展。采用田间试验,设置10个沼液施用量梯度,并以清水与常规化肥为对照。研究施用不同量沼液对土壤氮、磷、钾等养分含量的影响,并对田间各养分平衡状况进行综合分析。结果表明:当沼液施用量在108.0～126.0 t/hm~2时土壤全氮、碱解氮、全钾及速效钾含量较高,为1.35～1.42 g/kg、63.31～65.34 mg/kg、12.90～13.26 g/kg、45.45～59.25 mg/kg。随着沼液施用量的增加,土壤全磷含量(0.92～1.10 g/kg)变化不明显,而速效磷含量(8.49～18.85 mg/kg)较清水对照相比降低11.0%～59.9%。沼液处理组土壤氮、磷、钾元素的平衡范围为-25.61～66.68,-7.99～-15.34,-81.33～-145.82 kg/hm~2。当沼液施用量大于108.0 t/hm~2时,氮素能基本维持平衡。随沼液施用量增加,磷素亏损得到缓解,而钾素亏损加剧。施用适量沼液能提高土壤氮钾元素含量,但单施沼液难以满足土壤磷钾元素的平衡。因此,在实际生产过程中沼液施用量应控制在108.0～144.0 t/hm~2,并与10～15 kg/hm~2磷肥、115～120 kg/hm~2钾肥配合施用才能达到理想的效果。

Effects of Biogas Slurry on Soil Nitrogen, Phosphorus and Potassium Contents and Balance in Chengdu Plain

In order to explore the changes of soil nitrogen, phosphorus and potassium contents and nutrient balance after applying biogas slurry in alluvial paddy soil in Chengdu Plain, and realize the green development of biogas slurry resource utilization. Field experiments were conducted. Ten gradients of biogas slurry application rate were set up, and clear water and conventional fertilizers were taken as control. The effects of different amounts of biogas slurry on soil nitrogen, phosphorus, potassium and other nutrients contents were studied, and the balance of nutrients in the field was comprehensively analyzed. The results showed that the contents of total nitrogen, alkali-hydrolyzed nitrogen, total potassium and available potassium were higher when the biogas slurry application rate was 108.0~126.0 t/hm², which were 1.35~1.42 g/kg, 63.31~65.34 mg/kg, 12.90~13.26 g/kg and 45.45~59.25 mg/kg. With the increasing of biogas slurry application, the total phosphorus content of soil (0.92~1.10 g/kg) did not change significantly, while the available phosphorus content (8.49~18.85 mg/kg) decreased by 11.0%~59.9% compared with the clear water control. The balance of nitrogen, phosphorus and potassium in the biogas slurry treatment groups were -25.61~66.68, -7.99~-15.34 and -81.33~-145.82 kg/hm². When the amount of biogas slurry was more than 108.0 t/hm², the nitrogen balance was basically maintained. With increasing of biogas slurry application, phosphorus deficit was alleviated, while the potassium deficit was aggravated. Applying appropriate amount of biogas slurry could increase the contents of nitrogen and potassium in soil, but it was difficult to meet the balance of phosphorus and potassium in soil by applying biogas slurry alone. Therefore, the application rate of biogas slurry should be controlled in the range of 108.0~144.0 t/hm² in the actual production, and combined with 10~15 kg/hm² phosphate fertilizer and 115~120 kg/hm² potassium fertilizer to achieve the desired effect.