Preliminary Study on Annual Dynamics of Nitrogen and Phosphorus Losses at Carya cathayensis Stand on Slope

A monitoring station was established in May 2016 at the closed zone of Carya cathayensis stand on slope in Lin’an, Zhejiang province, and investigation was carried out during June 2016 to May 2017 on annual changes of nitrogen and phosphorus losses. The results showed that it had significant linear positive correlation between runoff and precipitation (y = 1.351 0x + 126.040 5, R? = 0.797 9), meaning that the greater precipitation, the greater runoff. The range of total nitrogen (TN) was 2.54 - 3.47 mg·L-1, of the nitrate nitrogen (NO－3-N ) concentration was 0 - 2.79 mg·L-1. TN and NO－3-N concentration increased during June to August, then declined and remained relatively stable. The concentration of N in runoff was determined higher. The total phosphorus (TP) concentration ranged from 0.01 to 0.09 mg·L-1, and phosphate (PO3－4) from 0.01 to 0.02 mg·L-1. The concentration of P in runoff was determined lower.