[Soil nutrient leaching patterns in maize field under different fertilizations: an in situ study].

An in situ field experiment with lysimeter was conducted to study the effects of different fertilizations on the nutrient leaching loss from brown soil in the growth season of summer maize. The results showed that abundant rainfall and irrigation were the main factors affecting the leaching loss. The leaching amount was higher in the early growth period of summer maize, but decreased after then. The difference among different fertilization treatments also decreased with maize growth. Comparing with N fertilization, wheat stalk plus N application intensified the leaching. During the growth period of summer maize, the NO3- -N content in leached water in fertilization treatments had two peaks, while the NH4+ -N content had a trend of increased first and decreased then. The leaching loss of soil N was mainly in the form of NO3- -N. The accumulative leaching loss of NO3- -N was 12.90-46.53 kg * hm(-2), and that of NH4+ -N was 1.66-5.11 kg x hm(-2), both of which increased with increasing N application rate. The leaching rate of soil N was 6.53%-13.07% higher in treatment wheat stalk plus N application than in treatments of N fertilization, and 3.66%-10.10% higher in low N treatments than in high N treatments. The accumulative leaching loss of available P was only 0.148-0.235 kg x hm(-2), while that of available K was 7.08-13.00 kg x hm(-2). In the late growth period of summer maize, wheat stalk plus N application increased the leaching loss of soil available P and K, while nitrogen application affected it slightly.