早熟冬油菜品种各器官干物质及养分积累特征

Characteristics of dry matter and nutrient accumulation in various organs of early maturing winter rape

为制定合理的早熟冬油菜品种的施肥方案,以适宜"稻—稻—油"三熟制的早熟冬油菜高产栽培,于2018-2019年选用早熟品种湘油420、湘油103和常规熟期品种湘油1035、湘杂油710×1035开展田间小区试验,播种45 d后间隔15~20 d取样,监测各器官干物质积累动态变化及氮、磷、钾养分积累动态,比较早熟与常规熟期冬油菜品种各器官干物质积累及养分吸收规律。结果发现:早熟品种干物质和养分积累高峰主要分布在开花期—角果发育期,且净增量最大时期出现较晚,明显延后于常规熟期品种(苗期—开花期)。两种熟期品种叶部干物质及养分积累最大的时期均为苗期,但该期叶部干物质和养分净增量占比早熟品种低于常规熟期品种,干物质净增量占比平均低约7个百分点,氮、磷、钾素净增量占比平均低约19、25和18个百分点。两种熟期品种茎部干物质净增量最高时期均为开花期,而积累次高时期,早熟品种(角果发育期)滞后于常规熟期品种(蕾薹期);茎部养分积累趋势两种熟期品种间差异较小。早熟品种根部干物质净增量在开花期最大,常规熟期品种在苗期或开花期最大;早熟品种根部养分积累明显迟于常规熟期品种,主要表现在两种熟期品种氮素净增量均在苗期最大,但其占比早熟品种(41.8%~55.2%)低于常规熟期品种(57.0%~63.0%),磷素和钾素净增量早熟品种在蕾薹期或开花期(两个品种不同)最大,常规熟期品种在苗期最大。生殖器官干物质积累趋势两种熟期品种间差异较小,早熟和常规熟期品种均在角果发育期净增量最大;早熟品种生殖器官氮素净增量在开花期和角果发育期相差较小,而常规熟期品种主要发生在开花期(62.0%~71.7%),早熟品种磷素净增量主要发生在角果发育期(61.0%~73.8%),而常规熟期品种开花期和角果发育期相差较小,钾素积累趋势与磷素类似,只是不同熟期品种间的差异相对小于磷素,说明早熟品种的生殖器官养分积累也相对滞后,其中氮素和磷素的滞后比钾素明显。综上,认为相较于常规熟期品种,早熟品种各器官干物质和养分积累高峰出现不同程度的延后。因此,在早熟品种种植中,可采用基肥+追肥的施肥措施或应用缓控释肥,且相对于常规熟期品种适当增加追肥比例或缓控释肥的后期养分释放比例。

To provide reference for optimal fertilization scheme on high yield early maturing winter rape(Brassica napus L.),experiments were carried out to compare differences of dry matter accumulation and nutrient absorption among various organs of early maturing cultivars(EMC)suitable for rice-rice-rape tri-ripening with conventional maturity cultivars(CMC).From 2018 to 2019,EMCs(Xiangyou 420,Xiangyou 103)and CMCs(Xiangyou1035,Xiangzayou 710×1035)were planted for field plot experiments.Samples were collected from plants 45 days after sowing at an interval of 15-20 days.Dynamic changes of dry matter accumulation and nutrient accumulation of N,P and K in each organ were detected.Result showed that dry matter and nutrient accumulation peaks of EMC were mainly distributed in flowering-silique filling stages,and the maximum net increment period appeared later than that of CMC(seedling-flowering stages).The maximum accumulation of leaf dry matter and nutrients occurred in seedling stage for both cultivars,but net increment of leaf dry matter and nutrients of EMC were about 7 percentage points lower than that of CMC at this stage,and net increment of N,P and K were about 19,25 and 18 percentage points lower on average.The maximum dry matter net increment of stem for both cultivars was in flowering stage,while net increment of EMC(silique filling stage)was later than CMC(bolting stage)in the second high stage.Little difference between the two cultivars for nutrient accumulation in stem was found.The largest dry matter net increment in root was at flowering stage of EMC,and at seedling or flowering stage for CMC.The root nutrients accumulation in EMC was significantly later than that in CMC,which mainly showed that the nitrogen net increment of both cultivars was the largest in seedling stage,but the proportion of EMC(41.8%-55.2%)was lower than that of CMC(57.0%-63.0%).Phosphorus and potassium net increment of EMC were the largest in bolting or flowering stage(different between the two cultivars),while that of CMC were the largest in seedling stage.The dry matter accumulation trends of reproductive organs had little difference,and the net increment was the largest in silique filling stage for both.The nitrogen net increment in reproductive organs of EMC was less different in flowering and silique filling stage,while that of CMC was mainly in flowering stage(62.0%-71.7%).The largest net phosphorus increment of EMC was mainly in silique filling stage(61.0%-73.8%),while that of CMC had little difference between flowering and silique filling stage.The accumulation trend of potassium was similar to that of phosphorus,but the difference between two cultivars was relatively smaller than that of phosphorus.Results indicated that the reproductive organs nutrient accumulation of EMC was later than CMC,and the lag of nitrogen and phosphorus were more obvious than those of potassium.In conclusion,dry matter and nutrient accumulation peaks of EMC organs were delayed compared to CMC.Therefore,the fertilization measures of base fertilizer+topdressing or controlled-release fertilizers could be adopted in EMC planting,and the ratio of topdressing fertilizer(or controlled-release fertilizer)in the later stage could be appropriately increased.