In order to relieve serious erosion of bare soil in the northwest sand area,20 rapeseed varieties,belonging to three rapeseed types,were used as materials to measure root indexes,including the total root length,root surface area,root volume,root dry mass,main root length,main root diameter,the total root length of diameter less than 2 mm,root tips numbers,and nutrient indexes of rhizosphere soil such as total nitrogen mass fraction,available phosphorus mass fraction,available potassium mass fraction and organic matter under the same cultivation pattern in mature period.The correlation analysis was carried out to explore relationship between root system indexes and soil nutrients of rapeseed rhizosphere.The results showed that indexes of rapeseed root and soil nutrient of rhizosphere had obvious differece among different types and different varieties within the same type of rapeseed.(1)Compared with Brassica juncea L.,Brassica napus L.and Brassica campestris L.had higher total root length,root surface area,root tips number,the total root length of diameter less than 2 mm generally,specifically,the root surface area of Brassica napus L.was 15.10％-94.00％ higher than that of Brassica juncea L.;Brassica juncea L.had the largest root volume and root dry mass,and 11.26％ and 12.39％ higher for average root volume and 49.77％ and 43.14％ higher for average root dry mass than Brassica campestris L.and Brassica napus L.,respectively;the main root length and main root diameter of Brassica juncea L.and Brassica napus L.were higher than those of Brassica campestris L.;(2)The total nitrogen,available potassium and organic matter mass fraction of rhizosphere soil in three types of rapeseed showed same trend:Brassica juncea L.＞ Brassica campestris L.＞ Brassica napus L.;available phosphorus mass fraction had a descending order of Brassica campestris L.,Brassica juncea L.,and Brassica napus L.(3) Correlation analysis showed that the total root length,root surface area,root tips number,total root length of diameter less than 2mm had a negative correlation with nutrient indexes.Higher root surface area,root length and root tip number were able to promote nutrient uptake,decreasing the nutrient mass fraction in the soil.It was suggested that Brassica juncea L.could be cultivated to fix sand and increase soil fertility in area with bare soil and easily eroded;Brassica napus L.could be planted for economic output in area with better water and fertilizer condition.%为缓解西北风沙区冬季地面裸露、风蚀严重的问题,以3种油菜类型共20个油菜品种为试材,在相同的栽培条件下于油菜成熟期分析油菜总根长、根表面积、根体积、根干质量、主根长、主根直径、直径小于2mm的总根长、根尖数等根系指标及油菜根际土的全氮、速效磷、速效钾、有机质质量分数的差异,并进行了相关性分析,旨在探索不同类型不同品种油菜根系差异以及根系对根际土壤养分的影响,进而为选择出根系发达的油菜类型和油菜品种增加相应的实践经验.结果表明,不同类型油菜、同一类型不同品种油菜间的根系指标及根际土养分质量分数存在显著差异,表现为:(1)甘蓝型和白菜型油菜的总根长、根表面积、根尖数、直径小于2 mm的总根长普遍大于芥菜型,其中甘蓝型油菜的根表面积相对芥菜型提高15.10％～94.00％;芥菜型油菜的根体积和根干质量最大,其中芥菜型油菜平均根体积分别比白菜型、甘蓝型油菜平均根体积提高11.26％、12.39％,平均根干质量分别减少49.77％和43.14％;芥菜型和甘蓝型油菜的主根长和主根直径普遍大于白菜型油菜.(2)3种油菜类型根际土壤全氮、速效钾、有机质质量分数大体上符合芥菜型＞白菜型＞甘蓝型的趋势,速效磷质量分数表现为白菜型＞芥菜型＞甘蓝型.(3)油菜总根长、根表面积、根尖数、直径小于2 mm的总根长与各养分指标呈负相关;油菜根表面积、根长、根尖数越大,养分吸收越多;芥菜型油菜主根发达,生物量大,可在土壤贫瘠、易风蚀的区域种植用于防风固土,培肥地力;甘蓝型油菜根系表面积大,可在水肥条件较好的地方种植用于收获经济产量.
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