【摘要】 盆栽及田间试验表明,土壤的全氮和有机质能稳定地反映土壤的供氮能力,是土壤肥力的重要指标。但其变动范围较小,灵敏性不高,难以在实际中应用。土壤中的 NO₃^--N 易于测定,又能较灵敏地在反映旱地土壤供氮水平及供氮潜力,有着实际应用的前景。通气培养法所矿化的氮素与作物吸氮量有良好的相关性,淹水培养法效果不佳。碱解氮法和 KCI 煮沸法所浸取出的可矿化氮与作物吸氮量关系密切,而 EUF 法所析滤出来的 NO₃^--N 与 KCI 直接浸取出来的数量基本一致。在旱地,任何方式得到的可矿化氮（包括碱解,通气培养,淹水培养等）,只要把土壤起始的NO₃^--N 包括在内,与作物吸氮量的相关系数显都著提高。更多还原

【Abstract】 Several pot experiments and field trials show that soil organic matter and total N canstably reflect soil N supplying-capacity,and are the important indices of soil fertility.However,their range of variatons is small,and their sensitivity is low,and therefore it is difficult toput them into practice.Soil nitrate is easy to be determined and is more sensitive to refectingsoil N supplying level and potential,and has bright prospect for use in practice.The mineral-ized N obtained by aerobic incubation is well correlated with N uptake by crops,but the Nreleased by water logged incubation is not.Also,good correlations exist between N releasedby NaOH hydrolysis or by boiling KCl and plant uptake N,and the amount of NO₃-N re-leased by EUF is much similar to that extracted by KCl.On dryiands,if the initial NO₃-N isincluded in the mineralized N obtained by any method（including NaOH-hydrolyzingmethod,aerobic and inaerobic incubation methods）,the correlation between the obtained Nand plant uptake N is significantly increased.更多还原