【摘要】 为明确小麦根系时空分布及其与土壤有效养分含量之间的相互关系，于2020—2021年进行大田试验，采用裂区设计，主处理为品种，分别选用大穗品种周麦30和多穗品种周麦32，副处理为种植密度，设置1.2×10⁶、2.4×10⁶、3.6×10⁶苗·hm^-2 3个密度。使用长方体铁盒（20 cm×5 cm×20 cm）在麦行上、行距1/4处、行距1/2处分别取0～20 cm和20～40 cm土层的样品。分析冬前期、返青期、拔节期、开花期、灌浆期、成熟期不同位点小麦根系形态数量性状（根长密度、平均根直径、根体积、根总表面积）及土壤碱解氮、有效磷和速效钾含量。结果表明，随着生育时期的推进，根总表面积、根长密度、根体积表现为先升高后降低的单峰曲线变化趋势；0～20 cm土层平均根直径呈“W”形曲线变化趋势，20～40 cm土层平均根直径呈“V”形曲线变化趋势。小麦根系垂直分布状况表现为：0～20 cm土层中根总表面积、根长密度、根体积均显著高于20～40 cm土层；20～40 cm土层平均根直径高于0～20 cm土层。小麦根系水平分布状况表现为0～20 cm土层的小麦根总表面积、根体积、根长密度大小均为行上>行距1/4处>行距1/2处，平均根直径在行上最大；20～40 cm土层的小麦根总表面积、根长密度、根体积水平分布较为均匀，在行距1/4处略大。0～20 cm土层，中种植密度下周麦32的根总表面积、根长密度、根体积最大，低种植密度下周麦30的平均根直径最大；随着种植密度的增加，根总表面积、根长密度、根体积在行距1/4处和行距1/2处的占比逐渐增加，其中周麦32表现更为明显。整个生育时期内，0～20 cm和20～40 cm土层的根长密度、根总表面积与土壤碱解氮、有效磷、速效钾含量均呈极显著负相关关系；平均根直径与土壤碱解氮、有效磷、速效钾含量均呈显著正相关关系，此外，在0～20 cm土层，根体积与土壤碱解氮、有效磷、速效钾含量呈负相关关系，在20～40 cm土层，根体积与土壤有效磷含量呈极显著负相关关系。综上所述，上层（0～20 cm）麦田根系的水平分布表现为距麦行越远根系越少；而土壤有效养分含量则表现为距麦行越远养分含量越高。周麦32种植密度为2.4×10⁶苗·hm^-2时根量最大；随着种植密度的增加，距麦行越远处的根量占比越大，周麦32表现尤为明显。本研究结果可为协调土壤养分供应与小麦养分需求之间的时空差异，提高土壤养分吸收利用效率提供理论依据。更多还原

【Abstract】 The current study aims to clarify the spatiotemporal distribution of wheat root and its relationship with soil available nutrients content.The research was carried out to provide a technical support for effective absorption and utilization of nutrients and ensuring the high and stable yield of wheat.During the wheat growing seasons from 2020 to 2021,a split block design was employed with two wheat cultivars,Zhoumai 30of large-spike cultivar and Zhoumai 32 of multi-cultivar,and three planting density,which were 1.2×10⁶,2.4×10⁶ and 3.6×10⁶ plants·hm^-2.In 0～20 cm and 20～40 cm soil layer the cubic iron box （20×5×20 cm） was used to get the samples from just above the wheat row,be situated in 1/4 row space,and be situated in 1/2 row space.Root morphological quantitative characteristics （root length density,average root diameter,root volume and total root surface area） and soil available nitrogen,soil available phosphorus and soil available potassium content were determined.The results showed that,in 0～20 cm and 20～40 cm soil layers,total root surface area,root length density and root volume were first increased and then decreased with the development of growing period.In 0～20 cm soil layers,the curve of average root diameter was shaped as a W with the development of growing period.In 20～40 cm soil layers,the curve of average root diameter was shaped as an N with the development of growing period.In the vertical distribution of wheat root,total root surface area,root length density and root volume in 0～20 cm soil layer were significantly higher than those in 20～40 cm soil layer.Average root diameter in 20～40 cm soil layer was higher than that in 0～20 cm soil layer.In the whole growing period,the horizontal distribution of total root surface area,root length density,root volume,in 0～20 cm soil layer was showed as the just above the row>be situated in 1/4 row space>be situated in 1/2 row space.In 0～20 cm soil layer,average root diameter was the highest on just above the row.In soil layer of 20～40 cm,root distribution was relatively uniform,total root surface area,root length density and root volume were the highest on where be situated in 1/4 row space.In 0～20 cm soil layers,root length density,root volume and total root surface area of Zhoumai 32 were the highest at planting density 2.4×10⁶ plants·hm^-2.In 0～20 cm soil layers,average root diameter of Zhoumai 30 was the highest at planting density 1.2×10⁶ plants·hm^-2.The proportion of root length density,root volume and total root surface area in be situated in 1/4 row space and be situated in 1/2 row space increased with increasing planting density,and Zhoumai 32 is even more obvious.In0～20 cm and 20～40 cm soil layers,root length density and total root surface area were significantly negatively correlated with contents of soil available nitrogen,soil available phosphorus and soil available potassium during the whole growing period.In 0～20 cm and 20～40 cm soil layers,average root diameter was significantly positively correlated with contents of soil available nitrogen,soil available phosphorus and soil available potassium during the whole growing period.In 0～20 cm soil layer,root volume was negatively correlated with contents of soil available nitrogen,soil available phosphorus and soil available potassium during the whole growing period.In 20～40 cm soil layer,root volume was significantly negatively correlated with content of soil available phosphorus during the whole growing period.These results suggested that the horizontal distribution of root biomass,the further away from the wheat row the less the root biomass,in 0～20 cm soil layer.The horizontal distribution of soil available nutrients content,the further away from the wheat row the more the soil available nutrients content.The root biomass of Zhoumai 32 was the highest at planting density 2.4×10⁶ plants·hm^-2.The proportion of root biomass of the further away from the wheat row the increased with increasing planting density,and Zhoumai 32 is even more obvious.The results of the current study provide guidelines for the coordinated spatiotemporal differences between soil nutrient supply and wheat nutrient demand and improving the efficiency of soil nutrient absorption and utilization.更多还原