Zhang Xuelin, Wang Qun, Xu Jun, Gilliam Frank S, Tremblay Nicolas, Li Chaohai
Incubation Base of National Key Laboratory for Physiological Ecology and Genetic Improvement of Food Crops in Henan Province, China, Collaborative Innovation center of Henan Grain Crops, Agronomy College, Henan Agricultural University, 95 Wenhua Road, Zhengzhou, 450002, China.
Department of Biological Sciences, Marshall University, Huntington, WV 25755-2510, United States of America.
PLoS One. 2015 Jan 30;10(1):e0115649. doi: 10.1371/journal.pone.0115649. eCollection 2015.
Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha(-1)) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha(-1) has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0-10 cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with higher rates occurring in August and coinciding with the R1 stage of maize growth. Soil NO3(-)-N contributed to more than 60% of inorganic N flux during maize growth. Cumulative NH3 volatilization increased with N additions, with total NH3 volatilization during maize growth accounting for about 4% of added N. Relative to the control, mean maize yield in the fertilizer treatments increased by 17% and 20% in 2009 and 2010, respectively. However, grain yield, aboveground biomass, and plant N accumulation did not increase with added N at levels > 215 kg N ha(-1). These results suggest that the current N rate of 300 kg N ha(-1) is not only excessive, but also reduces fertilizer efficacy and may contribute to environmental problems such as global warming and eutrophication of ground water and streams.
氮肥施用可能会影响土壤氮矿化和淋溶，并能增强氨挥发，从而影响作物产量。2009年和2010年在中国黄淮海地区的一个玉米田进行了一项氮肥试验，设置了五个施氮水平（0、79、147、215和375千克氮公顷-1），在120天的玉米生长期间，该地区常规向土壤施用超过300千克氮公顷-1。测定了净氮矿化、无机氮通量（0 - 10厘米）、氨挥发以及玉米产量对氮肥施用的响应。在生长期间，净氮矿化和硝化作用随季节变化，8月份速率较高，与玉米生长的R1阶段一致。在玉米生长期间，土壤中硝酸根氮占无机氮通量的60%以上。氨挥发累积量随施氮量增加而增加，玉米生长期间氨挥发总量约占施氮量的4%。相对于对照，2009年和2010年施肥处理的玉米平均产量分别提高了17%和20%。然而，当施氮量超过215千克氮公顷-1时，籽粒产量、地上生物量和植株氮积累量并未随施氮量增加而增加。这些结果表明，目前300千克氮公顷-1的施氮量不仅过高，而且降低了肥料效率，可能会导致全球变暖和地下水及溪流富营养化等环境问题。
