不同施肥与生物质炭配施对水稻田面水氮磷流失及产量的影响

Effects of Reducing Nitrogen and Biomass Carbon Fertilization on Loss of Nitrogen and Phosphorus in Surface Water of Paddy Field and Grain Production

通过研究减氮施肥及施用生物质炭对田面水氮磷流失风险和水稻性状的影响,结果表明:不同施肥处理田面水总氮、溶解性氮、铵态氮浓度均在施肥后第2天达到最高,然后迅速下降,并于7d后趋于稳定,稳定后浓度分别是顶峰值的5.6%～16.3%,8.4%～23.7%和25.0%～46.1%;不同施肥处理田面水总磷浓度在施肥后第3天达到最高,而后迅速下降,一周后趋于稳定;可溶磷浓度在施肥后4～5d内处于一个平稳的状态,而后平缓下降至施肥前水平。氮磷浓度在减氮(20%)施肥条件下与常规施肥相比均降低。减氮施肥对产量的影响不大,但减氮施肥结合生物质炭处理水稻产量与常规施肥相比提高了24.6%,达到7 391.5kg/hm2;减氮施肥降低了氮素流失风险,但减氮施肥结合生物质炭处理则明显提高田面水中总磷的浓度,增加磷素流失的风险。在施肥后1周内是控制氮磷流失风险的最佳时期,此时若遇暴雨,将导致氮磷随径流大量流失。

The influence of fertilizer of reducing nitrogen and biomass carbon on loss risk of nitrogen and phosphorus in surface water of paddy field and paddy character was studied.The results showed that the concentration of total nitrogen,soluble nitrogen and ammonium nitrogen in surface water of paddy field with different fertilization treatments all reached the highest on the second day after fertilization,then fell rapidly,and tended to be stable a week later.The stable concentration increased by 5.6%～16.3%,8.4%～23.7% and 25.0%～46.1%compared to the peak concentration.Total phosphorus concentration in surface water of paddy field with different fertilization treatments reached the highest on the third day after fertilization,then fell rapidly,and tended to be stable a week later.Soluble phosphorus concentration stayed a steady state in 4 ～5dafter fertilization,then gently fell to the value before fertilization.Nitrogen and phosphorus concentration of reducing nitrogen(20%)fertilizer were lower than that of normal fertilization.Reducing nitrogen fertilizer had little influence on grain production,but the treatment of reducing nitrogen fertilizer combined biomass carbon increased the production by 24.6%compared with normal fertilization,with the production reached to 7 391.5kg/hm2.Reducing nitrogen fertilizer reduced the risk of nitrogen loss,but combined biomass carbon obviously improved total phosphorus concentration in the surface water of paddy field,and increased the risk of phosphorus loss.The best period of controlling nitrogen and phosphorus loss was in a week after fertilization.If encountering rainstorm at this time,it would lead to loss of nitrogen and phosphorus with runoff.