油蔬两用油菜干物质积累及氮磷钾养分的吸收利用

Dry matter accumulation and NPK absorption and utilization of rapeseed for oilseed-vegetable

为了解油蔬两用生产方式下油菜养分吸收利用特性以合理施肥,通过两年定点取样,以不摘薹处理为对照,比较油菜现蕾摘薹后至成熟期间甘蓝型油菜品种的干物质积累、养分吸收与分配的差异。结果发现:摘薹后油菜生育期、分枝结构、干物质积累、养分吸收利用特性等均发生了改变。与不摘臺相比,摘薹后油菜籽粒产量降低,整株干物重增多,生育期延长8d,分枝发生提前,二次分枝增多(达每株19. 2枝),籽粒产量主要来自二次分枝。氮磷钾三种元素含量随生育进程降低,成熟时在角果中的含量大于根茎。摘薹后20d内,由于创伤的修复导致植株干物质积累量、氮磷钾养分吸收量增加缓慢。摘薹20d后,植株开始快速吸收养分;至成熟时,摘薹处理氮磷钾养分的积累更高。摘薹后油菜冠层结构以二次分枝为主、一次分枝为辅,二次分枝花果干物重、氮素积累量均高于一次分枝;而不摘薹处理一次分枝干物重和氮素积累量最高,主茎次之,二次分枝最低。油菜摘薹后生育期延长,干物质和养分积累持续时间变长。可见,油蔬两用的油菜需肥特性与常规油菜不同,需要结合特性研究具体的肥料运筹方式。

To achieve effective fertilizer rates on rapeseed(Brassica napus L.) for oilseed-vegetable dual purposes,plant nutrient traits were investigated on stalk-cut and stalk-free(CK) plants from bolting to mature.2 years data of dry matter accumulation,nutrient absorption and distribution were compared.Results showed that the growth period,branch structure,dry matter accumulation,nutrient absorption and utilization on stalk-cut rapeseed were changed dramatically.After cut,plants had lower seed yield but greater dry matter.It had 8 d extension on growth period.The plants were early branched,and had more secondary branches with an average of 19.2 per plant.The seed yield was mainly obtained from the secondary branches.The content of NPK(nitrogen,phosphorus and potassium) decreased with the growth processes,and the content in siliques was much higher than that in root and stem during maturing.Because of the wound,dry matter accumulation and NPK absorption were increased slowly during the first 20 d after cut.Then the absorption increased rapidly.NPK accumulation on stalk-cut plants was higher than that of stalk-free during maturing.For stalk-cut plants,the secondary branches were dominant in canopy,which had more flowers and greater silique dry matter as well as N accumulation than that of the primary branches.Because of longer growth period,the duration of dry matter and nutrient accumulation were prolonged after the cut.In summary,stalk-cut rapeseed had different characteristics on fertilizer requirement from oilseed-vegetable dual-purpose production of rapeseed,which suggested a very different fertilization management.