| 灌溉与施氮对黑河中游新垦沙地农田土壤硝态氮动态的影响 |
| 摘要点击 2650 全文点击 1587 投稿时间：2007-07-17 修订日期：2007-11-21 |
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| 中文关键词 灌溉 施氮 硝态氮动态 新垦沙地农田 |
| 英文关键词 irrigation nitrogen supply nitrate-nitrogen dynamic recently reclaimed sandy farmland |
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| 中文摘要 |
| 研究了黑河中游绿洲边缘区新垦沙地农田不同灌溉量 (分别为估算春小麦生育期需水量的0.6、0.8、1.0倍)和不同施氮量 (0、140、221和300 kg·hm-2) 对春小麦不同生育期土壤硝态氮含量及分布动态的影响.结果表明，施氮量为硝态氮淋溶的决定因素，土壤剖面中硝态氮的含量随着施氮量的增加而增加，当施氮量在0～140 kg·hm-2之间时，硝态氮的淋溶较为缓慢，而在221～300 kg·hm-2范围时硝态氮的含量显著增加，这表明当施氮量高于221 kg·hm-2时易引起硝态氮的淋溶.收获期土壤的硝态氮含量明显低于开花期，且硝态氮存在显著差异的土层深度变浅.在综合4个施氮处理的情况下，不同灌溉处理同一土层土壤硝态氮的含量无显著差异(p<0.05)，这一结果表明灌溉量对春小麦生育期土壤硝态氮淋溶过程的影响要小于施氮量.不同灌溉处理同一土层土壤硝态氮含量的差异因施氮水平的不同而异，多数情况下，低灌溉处理 (I0.6) 与中等灌溉处理(I0.8)的土壤硝态氮含量高于高灌溉处理(I1.0)，同时具有显著硝态氮含量差异的土层深度随施氮量的增加而递增，说明随着灌水量的减少硝态氮向下淋溶量也相应下降. |
| 英文摘要 |
| 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 (NO-3-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·hm-2,denoting N0,N140,N221 and N300 respectively］ as the main-plot and split-plot,respectively.Our results show that the rate of N is the key factor in influencing NO-3-N content and its leaching.The content of NO-3-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·hm-2 and 300 kg·hm-2. In addition,NO-3-N leaching is relatively less apparent at the N rates in the range of 0-140 kg·hm-2,but this effect became significant when the N rates exceeded 140 kg·hm-2. Our results also show that NO-3-N contents were〖JP2〗 generally higher at the anthesis stage than at the harvest stage within the same soil layer.The observed differences in NO-3-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 NO-3-N leaching than irrigation treatments.Although the among-irrigation differences of NO-3-N contents within the same soil layer varied with N level,there was a tendency that NO-3-N content of I1.0treatment 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 NO-3-N leaching with decreased irrigation levels. |
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