油菜机械直播同步分层施肥对根系构型和抗倒伏能力影响

Effects of synchronous layered fertilization with machinery on the root architecture and lodging resistance of rape

为探明油菜精量联合直播同步分层施肥机械作业条件下,深浅层施肥比例对油菜根系生长、植株抗倒伏能力和产量等农艺性状的影响,该研究选用“华油杂62”油菜品种作为供试作物,在施肥量600 kg/hm^(2)条件下,以10 cm定位侧深施肥CK1和机械旋耕浅层混施CK2作为对照,设置机械旋耕浅层混施-定位侧深施肥量分层比例为1∶3(FL)、1∶1(FM)和3∶1(FH)3个施肥处理,于2020年和2021年在长江中游冬油菜区开展田间试验,研究不同分层施肥处理对油菜根系分布、耕层土壤坚实度变化、倒伏指数和产量的影响。结果表明,分层深施处理能显著(P<0.05)改善油菜根系构型并促进根系下移,平均根表面积、根体积、根干质量和主根长分别是CK1处理的1.58、1.47、1.29和1.16倍,是CK2处理的3.63、2.79、1.46和1.28倍,且土壤坚实度相较于CK1和CK2处理平均分别降低4.91%和15.25%。不同分层施肥处理的油菜主根长、根表面积、根体积和根干质量在处理间从大到小依次均为:FM、FH、FL;FH处理植株的根茎粗、倒伏角度、抗折力分别是FM处理的1.11、1.25和1.31倍,倒伏指数相较于FM处理平均降低了26.90%,但植株田间倒伏角度比FM处理增加了25.14%。分层深施肥处理的产量、单株分枝数、角果数和千粒质量均显著(P<0.05)大于定位深施和机械混施处理,其中FM处理平均产量与FL、FH、CK1和CK2相比,分别提高9.85%、16.35%、26.88%和37.75%。综合考虑不同施肥处理下冬油菜根系分布、土壤坚实度、倒伏指数和籽粒产量,分层深施肥处理中FM处理为田间机械化直播冬油菜实现高产且抗倒伏的较优施肥方式,研究为提升油菜机械直播农机农艺融合和肥料运筹策略提供了理论依据和技术支撑。

An appropriate fertilizer application can be one of the most important indicators for resistance to the downfall and high yield of direct sowing rape.Among them,the fertilizer placement and application rates can dominate the root and plant growth,development,and lodging resistance of winter rapeseed.This study aims to investigate the effects of the different ratios of layered fertilization in the deep and shallow layers under the precision combined seeder on agronomic characteristics,such as the root growth,plant resistance to lodging,and yield of rapeseed.The agricultural machinery and agronomic techniques were integrated to further improve the mechanical application fertilization of winter rapeseed."Huayouza 62" rapeseed variety was selected as the test crop at the fertilization rate of 600 kg/hm^(2).The control group was taken as the side deep fertilization of CK1 on the 10 cm positioning under the seed,and the shallow layer mixing fertilization of CK2.Three treatments of deep fertilization were set as the shallow and deep layer fertilization ratios of 1:3(FL),1:1(FM),and 3:1(FH) experimental groups.A total of five fertilization treatments and field trials were conducted in 2020 and 2021.The experiment site was located in the winter rapeseed area in Jingzhou,Hubei Province in the middle reaches of the Yangtze River basin.A measurement was performed on the root growth characteristics,soil firmness,shoot fresh weight,stem bending resistance and yield of rapeseed during the harvest period.A systematic analysis was then made on the five treatments,in terms of the root distribution,soil penetration resistance of topsoil,lodging index,and yield of rapeseed.The results showed that the layered deep fertilization significantly promoted the root downward migration and the root architecture of rapeseed.The average values of root surface area,root volume,root dry weight,and taproot length were 1.58,1.47,1.29,and 1.16 times higher than those in the CK1treatment,while 3.63,2.79,1.46,and 1.28 times higher than those in the CK2 treatment,respectively.Meanwhile,the average soil penetration resistance decreased by 4.91% and 15.25%,respectively,compared with the CK1 and CK2 treatments.The overall performance was ranked in the descending order of the FM FH FL,in terms of the taproot length,root surface area,root volume,and root dry weight in the different layered fertilization treatments.The rape plant of root stem diameter,lodging angle,and fracture resistance of the FH treatment were 1.11,1.25,and 1.31 times higher than those of the FM treatment.The lodging index decreased by 26.90% on average,but the field lodging angle increased by 25.14%,compared with the FM treatment.The yield,number of branches per plant,number of corner fruit,and thousand-grain weight of layered deep fertilization treatment were significantly higher than those of positioned deep fertilization and mechanical mixing fertilization treatment.the average rapeseed yield of FM treatment increased by 9.85%,16.35%,26.88%,and 37.75%,respectively,compared with the FL,FH,CK1,and CK2.The root distribution,soil penetration resistance,lodging index,and grain yield of winter rapeseed were considered under different fertilization treatments.The FM treatment was achieved in the better optimal fertilization for the high yield and lodging resistance of field mechanized direct sowing winter rapeseed.