Wang Qi, Li Feng-Rui, Zhang Zhi-Hui
Linze Inland River Basin Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China.
Huan Jing Ke Xue. 2008 Jul;29(7):2037-45.
Improper nitrogen (N) and irrigation management are major causes leading to deterioration in water environmental quality in the middle reaches of Heihe River basin. A controlled experimental study of different irrigation and N supply levels was therefore conducted in the Linze Inland River Basin Research Station, Chinese Academy of Sciences, to determine the influences of N addition and irrigation regime on the dynamics of nitrate-N (NO3(-) -N) distribution in soil profiles over the growing season of spring wheat. The experiment employed a completely randomized block split-plot design, with irrigation treatments [0.6, 0.8, 1.0 of the estimated evapotranspiration (ET), denoting I0.6, I0.8 and I1.0 respectively] and N addition treatments [0, 140, 221, 300 kg x hm(-2), denoting N0, N140, N221 and N30 respectively] as the main-plot and split-plot, respectively. Our results show that the rate of N is the key factor in influencing NO3(-) -N content and its leaching. The content of NO3(-) -N in the 0-200 cm soil profiles was found to increase with increased N rates, and in particular this increase was more pronounced when the N rates ranged between 221 kg x hm(-2) and 300 kg x hm(-2). In addition, NO3(-) -N leaching is relatively less apparent at the N rates in the range of 0-140 kg x hm(-2), but this effect became significant when the N rates exceeded 140 kg x hm(-2). Our results also show that NO3(-) -N contents were generally higher at the anthesis stage than at the harvest stage within the same soil layer. The observed differences in NO3(-) -N contents between the irrigation treatments of I0.6, I0.8 and I1.0 were insignificant across N rates. This finding suggests that N addition treatments may have greater impacts on NO3(-) -N leaching than irrigation treatments. Although the among-irrigation differences of NO3(-) -N contents within the same soil layer varied with N level, there was a tendency that NO3(-) -N content of I1.0 treatment was significantly lower than that of I0.8, and that of I06 irrigation treatment in the soil layer with significant differences in N contents. This result suggests declined NO3(-) -N leaching with decreased irrigation levels.
不合理的氮素（N）和灌溉管理是导致黑河中游流域水环境质量恶化的主要原因。因此，在中国科学院临泽内陆河流域研究站开展了不同灌溉和氮素供应水平的控制实验研究，以确定施氮量和灌溉制度对春小麦生长季土壤剖面中硝态氮（NO₃⁻-N）分布动态的影响。该实验采用完全随机区组裂区设计，灌溉处理[分别为估算蒸散量（ET）的0.6、0.8、1.0，分别表示为I0.6、I0.8和I1.0]和施氮处理[0、140、221、300 kg·hm⁻²，分别表示为N0、N140、N221和N30]分别作为主区和副区。我们的结果表明，施氮量是影响NO₃⁻-N含量及其淋失的关键因素。发现0-200 cm土壤剖面中NO₃⁻-N含量随施氮量增加而增加，特别是当施氮量在221 kg·hm⁻²至300 kg·hm⁻²之间时，这种增加更为明显。此外，在0-140 kg·hm⁻²的施氮量范围内，NO₃⁻-N淋失相对不明显，但当施氮量超过140 kg·hm⁻²时，这种影响变得显著。我们的结果还表明，在同一土层内，开花期的NO₃⁻-N含量一般高于收获期。在不同施氮量下，I0.6、I0.8和I1.0灌溉处理之间观察到的NO₃⁻-N含量差异不显著。这一发现表明，施氮处理对NO₃⁻-N淋失的影响可能大于灌溉处理。尽管同一土层内灌溉处理间的NO₃⁻-N含量差异随氮水平而变化，但存在一种趋势，即在氮含量有显著差异的土层中，I1.0处理的NO₃⁻-N含量显著低于I0.8处理，I0.6灌溉处理的NO₃⁻-N含量也较低。这一结果表明，随着灌溉水平的降低，NO₃⁻-N淋失减少。
