摘要： 通过田间试验，采用大口径根钻取样研究了华北平原冬小麦根系生长的基本规律及其氮、磷肥和水分对根系生长的影响。结果表明，冬小麦根系生长时间分布规律是冬前较快，越冬不停，拔节至抽穗最快，抽穗后生长减缓并达到最大；根长和根重的增长遵循Logistic模型。空间分布规律是：冬小麦根系随土层深度的分布，无论是根长还是根重都是由上到下逐渐减少，遵循指数递减模型。施用氮肥和磷肥能显著促进冬小麦根系的生长。水分亏缺限制冬小麦根系的生长，但使根系分布下移。灌溉不仅能促进小麦根系前期的生长，而且可以延缓小麦根系后期的衰亡。

关键词: 冬小麦, 根系, 氮, 磷, 水分亏缺

Abstract: Roots play an important role in water and nutrient uptake by crop. The investigation of root system development of winter wheat and the effect of nitrogen, phosphorus and soil moisture on its growth in the North Plain of China was made in 1990 and 1991. Roots were sampled by coring and the changes of root weight and length were determined in five development stages. The root weight growth rates were 0.845, 0.386, 1.921, 2.500 and 0.427g/m²· day and root length growth rates were 0.062, 0.0329, 0.310, 0.221km/m²· day in seedling, overwintering, jointing, heading and seed filling stages, respectively. The total root length and total root weight with time could be described by logistic growth function, and the exponential model was suggested for describing root system distribution with soil depth. N and P fertilizer application could promote the growth of winter wheat root system. Water stress reduced the root dry weight and root length, but root length and weight was greater in 0.3-1.20m depth under water stress than that of irrigated wheat. Irrigation could significantly increase roots in the stages of vegetative development and extend the root lifespan in the stages of reproductive development.

Key words: Winter wheat, Root system, Nitrogen, Phosphorus, Water stress