The effect of fertilization methods (1 cm and 5 cm of focus methods denoted as M1 and M2, 0~5 cm and 0~10 cm of soil mixed methods denoted as M3 and M4) and nitrogen fertilizer application (N 0, 0. 3, 0. 6, 0. 9, 1. 2 g/pot) on the bio-mass, root morphological parameters and nitrogen absorbing rice seedling were studied in order to provide information for appro-priate fertilization. The results showed that the biomasses of shoot and root of N0. 6 showed significant higher value compared to other treatments under the fertilizer applied in shallow soils of focus method (M1 and M2), increased by 17. 8% ~84. 8% and 13. 9% ~46. 9% respectively. The result of root morphological parameters showed that root morphological parameters of N0. 3 and N0. 6 were significantly higher than that of N1. 2. The biomasses of shoot and root of N1. 2 showed significant higher value com-pared to other treatments under the fertilizer in shallow soils of mixed method (M3 and M4), increased by 32. 6% ~36. 3% and 14. 9% ~16. 2% respectively. The root morphological parameters had the increasing trend with the N application rate increase. The nitrogen absorption had same tendency with biomass. The NRE of treatment M1 was higher than M2 , and M3 was higher than M4. Correlation analysis showed that the root morphological parameters and root nitrogen absorption had a significant rela-tionship with the shoot biomass and nitrogen absorption. In combination with root morphological parameters and nitrogen absorb-ing, both the fertilizer application in shallow soils by focus method under low nitrogen fertilizer, and by mixed method under high nitrogen fertilizer were beneficial to the improvement of the rice root morphology characteristics and nutrient absorption.%采用盆栽试验,研究施肥方式(点施于距土表1、5 cm土柱中心位置,分别记为M1、M2;距土表0~5、0~10 cm土壤与氮肥混匀施用,分别记为M3、M4)和氮肥用量(N 0、0.3、0.6、0.9、1.2 g/盆)对直播稻苗期生物量、 根系形态及氮素吸收的影响,以期为直播稻科学施用氮肥提供理论依据.结果表明,M1、M2施肥方式下N0.6处理地上部和根系生物量都显著高于其他处理,增幅分别为17.8%~84.8%和13.9%~46.9%,根系形态指标表现为N0.3和N0.6高于N1.2处理;M3、M4施肥方式下N1.2处理地上部和根系生物量都显著高于其他处理,增幅分别为32.6%~36.3%和14.9%~16.2%,根系形态指标有随着施氮量增加而增加的趋势.施肥方式和氮肥用量对氮素吸收量的影响趋势与生物量表现一致,氮素吸收利用率表现为点施条件下M1>M2,混施条件下M3>M4.相关分析结果表明,水稻地上部生物量及其氮素吸收与根系形态参数及氮素吸收量存在显著正相关关系.综上所述,低氮条件下浅层点施、 高氮条件下浅层混施有利于促进水稻苗期的生长发育,稳固良好的根系形态特性,增强其对养分的吸收利用.
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