桐乡市茭白种植氮磷变化规律及流失量研究

Study on nitrogen and phosphorus variation and loss in Zizania latifolia planting in Tongxiang

通过对桐乡市茭白整个生长期内施肥情况、排水规律及田表水/土壤氮磷含量调查,分析氮磷变化规律,并估算流失量。结果表明:茭白种植过程中田表水总氮和总磷最高值分别为150.00、18.80 mg/L,变化幅度大,主要受施肥和降雨影响;由于茭白对氮素需求高于磷素,土壤全氮呈波动下降趋势,总磷先波动上升后下降;土壤和田表水总氮之间无显著相关性,总磷之间存在中等程度直线相关关系。茭白种植氮磷主要随搁田排水流失,时间集中在12月至次年1月、4月和5月,茭白种植的氮、磷流失量分别为34.20~51.31、4.88~10.96 kg/hm^(2),磷流失量较大。桐乡市茭白种植污染控制的关键在于磷施肥量的控制,以及搁田期间集中排水的管控和收集处理,尤其4—5月施肥密集时段应重点管控。

Through investigation of fertilization,drainage patterns,and the contents of nitrogen and phosphorus in surface water and soil during the whole growth period of Zizania latifolia in Tongxiang city,the changes of nitrogen and phosphorus were analyzed and the amount of loss was estimated.The results showed that the maximum values of total nitrogen and total phosphorus in the field surface water during the cultivation of Zizania latifolia were 150.00 and 18.80 mg/L,respectively.The changes were large and mainly affected by fertilization and rainfall.Because the nitrogen demand of Zizania latifolia was higher than that of phosphorus,total nitrogen in soil fluctuated and decreased,while total phosphorus in soil fluctuated and increased first and then decreased.There was no significant correlation of total nitrogen between in surface water and in soil,but there was a moderate linear correlation of total phosphorus.The nitrogen and phosphorus loss of Zizania latifolia planting were mainly lost with the drainage.The period was concentrated in December to January of the following year,April and May.The total nitrogen and total phosphorus loss of Zizania latifolia planting were 34.20-51.31,4.88-10.96 kg/hm^(2),respectively,with large phosphorus loss.The key to pollution control of Zizania latifolia planting in Tongxiang city lay in the control of phosphorus fertilizer application amount,as well as the control,collection and treatment of centralized drainage during the field draining period,especially during the period of intensive fertilization from April to May.