| 摘要: |
| 【目的】研究长期施用马铃薯淀粉加工废水土壤的氮磷累积与分配特征，为指导马铃薯淀粉加工废水科学还田提供依据。【方法】测定马铃薯淀粉加工废水中全氮、全磷和总有机碳含量，并依据农田中废水施用量计算氮、磷和有机碳的年均投入量。采集连续施用8年马铃薯淀粉加工废水地块（还田地块）和未施用废水地块（对照地块）的土壤样品，分析其垂直剖面水解氮、硝态氮、有效磷累积与分配特征及氮磷淋失风险。【结果】还田地块随马铃薯淀粉加工废水年均施入的氮（以N计）、磷（以P2O5计）分别高达2 823和708 kg/hm2，分别是对照地块氮、磷投入量的10.8和4.1倍；还田地块随马铃薯淀粉加工废水年均施入的总有机碳为14.04 t/hm2，对照地块未投入有机碳。长期施用马铃薯淀粉加工废水后，还田地块0～250 cm土层土壤水解氮、硝态氮、有效磷含量分别为48.9～140.0，37.6～53.0和0.8～35.4 mg/kg，极显著高于对照地块的水解氮（10.8～73.2 mg/kg）、硝态氮（1.82～7.34 mg/kg）及有效磷（0.2～22.2 mg/kg）含量。还田地块和对照地块水解氮含量均随土壤剖面深度增加呈近似线性下降趋势；还田地块土壤硝态氮和有效磷含量随土壤剖面深度增加呈缓慢下降趋势，而对照地块土壤硝态氮和有效磷含量急剧下降至40～60 cm土层后缓慢下降。相比0～20 cm土层，还田地块200～250 cm土层中水解氮、硝态氮和有效磷含量降幅分别为65.07%，29.06%和97.74%，对照地块分别为85.24%，75.20%和99.10%。【结论】在宁夏固原气候条件下，长期、大量施用马铃薯淀粉加工废水后，农田土壤氮、磷淋失风险仍较小，但造成了水、肥资源的严重浪费，应根据《测土配方施肥技术规程》科学确定废水还田总量，避免造成废水养分浪费及环境污染风险。 |
| 关键词: 食品加工废水 废水还田 氮磷累积与分配 氮磷淋失 农田土壤 |
| DOI： |
| 分类号: |
| 基金项目:国家水体污染控制与治理科技重大专项（2017-ZX07602-001-005） |
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| Accumulation and distribution of nitrogen and phosphorus in soil with long-term application of potato starch processing wastewater |
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ZHAO Bochao,DOU Guangyu,WANG Xueting,et al
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| Abstract: |
| 【Objective】This paper studied the accumulation and distribution characteristics of nitrogen and phosphorus in soil with long term application of potato starch processing wastewater to provide basis for scientific return of potato starch processing wastewater to field.【Method】Total nitrogen,total phosphorus and total organic carbon contents in potato starch processing wastewater were determined and average annual inputs of nitrogen,phosphorus and organic carbon based on amount of wastewater applied in farmland were calculated.Soil samples from 8-year potato starch processing wastewater farmland (application) and non-application farmland (non-application) were collected to analyze vertical profiles of hydrolyzed nitrogen,nitrate nitrogen and available phosphorus accumulation,distribution characteristics and leaching risk of nitrogen and phosphorus.【Result】Nitrogen and phosphorus applied to farmland with wastewater were up to 2 823 and 708 kg/hm2 per year,which were 10.8 and 4.1 times of the inputs to non-application farmland,respectively.The total organic carbon applied to farmland from wastewater was 14.04 t/hm2 per year,while the control group had no organic carbon input.After long term application,contents of hydrolyzed nitrogen,nitrate nitrogen and available phosphorus in 0-250 cm soil layer were 48.9 to 140.0,37.6 to 53.0 and 0.8 to 35.4 mg/kg,which were significantly higher than those of 10.8-73.2,1.82-7.34 and 0.2-22.2 mg/kg in non-application farmlands.The content of hydrolyzed nitrogen decreased linearly with the increase of soil depth in both application farmland and control farmland.The nitrate nitrogen and available phosphorus contents slowly decreased with the increase of soil depth in application farmland,while in control farmland it sharply decreased from surface to the layer of 40-60 cm and then decreased slowly.Compared with the 0-20 cm soil layer,contents of hydrolyzed nitrogen,nitrate nitrogen and available phosphorus in 200-250 cm soil layer of application farmland decreased by 65.07%,29.06% and 97.74%,while those of the control farmland were decreased by 85.24%,75.20% and 99.10%,respectively.【Conclusion】Under the local climatic conditions of Guyuan,Ningixa,the risk of nitrogen and phosphorus leaching from farmland was small after long-term application of potato starch processing wastewater,but it caused serious waste of water and fertilizers.The application of potato starch processing wastewater to field should be scientifically determined according to “Regulations for soil testing and formulated fertilization” to avoid waste of nutrients in wastewater and environmental pollution risks. |
| Key words: food processing wastewater waste water return N and P accumulation and distribution N and P leaching farmland soil |
