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作 者 ：叶优良1;2;李生秀1

期 刊 ：植物营养与肥料学报 2002年 8卷 3期 页码：310-317

关键词：土壤；起始NO3--N；供氮指标；测定方法；

Keywords:soil, initialnitratenitrogen, indexofsoilnitrogen-supplyingcapacity, methodsofmeasuringsoilnitrogensupplyingcapacity,

摘 要 ：在陕西省的澄城、永寿、杨陵 3地区选取有机质、全N、硝态N含量差异较大的 17个石灰性土壤 ,分别在淋洗与未淋洗土壤起始NO₃^--N后 ,利用盆栽试验探讨土壤NO₃^--N淋洗前、后 ,不同方法测定的已矿化N和可矿化N与小麦吸N量之间的相关性。结果表明 ,未淋洗土壤起始NO₃^--N ,用KCl直接浸取、KCl煮沸法所浸取以及通气培养前CaCl₂ 所淋洗的起始NO₃^--N均与小麦吸N量密切相关 ,相关系数 (r)分别为 0.934 ,0.856和 0.862 ,均达1%显著水准。与此相反 ,通气培养、淹水培养、沸水煮沸、碱性高锰酸钾、酸性高锰酸钾及碱解扩散等方法所提取的可矿化N与小麦吸N量间无显著相关。淋洗土壤起始NO₃^--N后 ,用KCl直接浸取、KCl煮沸法浸取以及通气培养前CaCl2 所淋洗的起始NO₃^--N与小麦吸N量之间的相关系数明显降低 ,达不到 5%的显著水准。而通气培养、淹水培养、沸水煮沸、碱性高锰酸钾、酸性高锰酸钾及碱解扩散等方法所提取的可矿化N与小麦吸N量之间相关系数却明显提高 ,都达到 5%或 1%的显著水平。其中变化最明显的是淹水培养 1周矿化出的NH₄⁺-N、通气正式培养 2周矿化出的NO₃^--N及碱解扩散出的NH₄⁺-N ,其与小麦地上部吸N量之间的相关系数 (r)分别由淋洗前的0.443,0.119,0.259增加到淋洗后的 0.866 ,0.767,0.763。说明可矿化N反映土壤供N能力不佳是因为受起始NO₃^--N的干扰和影响，在土壤NO₃^--N含量较高的情况下，要正确评价可矿化N测定方法必须考虑NO₃^--N的作用。

Abstract:Seventeen calcareous soils representing different organic matter,total N and NO₃^--N contents were sampled from Chengcheng ,Yongshou and Yangling area of Shannxi Province, and the soils with and without leaching of NO₃^--N were used for pot experiments using wheat as indicator to discuss the relationship between initial NO₃^--N and mineralizable N determined by various methods with wheat uptake N. The results showed that when initial NO₃^--N were not leached, soil initial NO₃^--N extracted by KCl directly and KCl boiling method, and leached by CaCl₂ before aerobic incubation were closely related with wheat N uptake, the correlation coefficients were 0.934, 0.856, 0.862, respectively, all reached at 1% significant level. On the contrary, it was no good relationship between mineralizable N extracted by aerobic incubation, water logging method, boiling water method, alkaline permanganate extraction, acid permanganate extraction and NaOH hydrolyzation diffusion method with wheat uptake N. When initial NO₃^--N were leached, the correlation coefficient between initial NO₃^--N extracted by KCl directly and KCl boiling method, and leached by CaCl₂ before aerobic incubation with wheat uptake N were decreased greatly, and could not reach 5% significant level. However, the correlation coefficients between mineralizable N extracted by aerobic incubation, water logging method, boiling water method, alkaline permanganate extraction, acid permanganate extraction and NaOH hydrolyzation diffusion method with wheat uptake N were raised obviously, and all reached 5% or 1% significant level. Of which, the NH₄⁺-N mineralized by one week waterlogging and NO₃^--N leached by two weeks formal aerobic incubation, as well as NH₄⁺-N extracted by Conway method varied greatly. The correlation coefficients between mineralizable N and uptake N of wheat above ground raised from 0.443, 0.119, 0.259 to 0.866, 0.767, 0.763, respectively. It showed that the poor effects of mineralizable N on reflecting soil N capacity were influenced and disturbed by initial NO₃^--N, warning researcher to pay more attention to correctly evaluate the function of mineralizable N when soil initial NO₃^--N is higher .

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