不同施肥条件下玉米田土壤养分淋溶规律的原位研究

Soil nutrient leaching patterns in maize field under different fertilizations:An in situ study

利用排水采集器法结合田间原位试验,研究了夏玉米不同施肥处理对棕壤土养分淋失的影响.结果表明:在夏玉米生长期内,影响玉米田土壤水分淋溶的主要因素是大量降雨和灌溉,夏玉米生长前期的土壤淋溶水量较大,但随夏玉米生育进程的推进而递减,各处理差异也逐渐减小;与施氮肥处理相比,秸秆还田配施氮肥处理可加剧土壤水淋溶.在夏玉米生长期内,施肥处理的土壤淋溶水硝态氮浓度均呈"双峰"曲线变化趋势,而铵态氮浓度则呈先升后降的变化趋势.玉米田土壤氮素淋失以硝态氮形式为主,其累计淋失量为12.90～46.53kg.hm-2,铵态氮的累计淋仅为1.66～5.11kg.hm-2,两种形态氮的淋失量都随施氮量的增加而升高.秸秆还田配施氮肥处理的氮素淋失率比单施氮肥处理高6.53%～13.07%,低氮处理的氮素淋失率比高氮处理高3.66%～10.10%;玉米田土壤速效磷的累计淋失量较小,仅为0.148～0.235kg.hm-2,而速效钾的累计淋失量较大,为7.08～13.00kg.hm-2.在夏玉米生长后期,秸秆还田配施氮肥处理使土壤速效磷淋失量升高,并可加剧土壤速效钾的淋失,而单施氮肥处理作用不明显.

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 NO^3- -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 ·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·hm^-2, while that of available K was 7.08-13.00 kg ·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.