油菜毯状育苗与机插移栽关键技术试验OA

To investigate the effects of uniconazole seed dressing,seeder parameters,nursery substrate,and transplanting date on seedling emergence,seedling quality,and yield of rapeseed carpet seedlings,an experiment was conducted using rapeseed cultivar Chuangza No.8 as material.Different doses of uniconazole(normal dose:2.5 g/20 kg seeds;half dose 1.25 g/20 kg seeds;and no dressing as control)and different sowing times after dressing(immediate sowing and sowing after 14 days of storage)were set up,and the germination energy,germination rate,and seedling growth indices were measured.The number of seeds sown per tray and the number of emerged seedlings were compared between two seeder parameters(40 and 70 gears).The effects of full substrate and semi-substrate(50%substrate+50%fine field soil)on seedling quality were analyzed.Using direct seeding on October 25th as the control,the pre-winter seedling traits and yields of three mechanical transplanting dates(October 30th,November 9th,and November 23rd)were compared.The results showed that uniconazole seed dressing reduced the germination energy and germination rate of rapeseed,and sowing after 14 days of storage further inhibited seedling emergence compared with immediate sowing after dressing.The seed dressing treatment promoted shorter and sturdier seedlings,shortened hypocotyl length,and increased the number of green leaves,with the half-dose treatment showing better comprehensive effects than the normal-dose treatment.When the seeder parameter was set to 70 gears,the number of seeds sown per tray ranged from 1 005 to 1 097 seeds,with an emergence rate of 54.1%-61.8%,indicating an appropriate density.Compared with the semi-substrate treatment,full-substrate nursery resulted in greener seedlings,longer roots,increase in fresh weight per plant,and no basal necrosis.The transplanting date experiment showed that the pre-winter seedling traits(leaf number 8.1,green leaf number 6.5,crown spread 30.1 cm,leaf area index 0.50)and yield(190.8 kg/667 m2)of the treatment transplanted on October 30th were superior to those transplanted on November 9th or direct-seeded on October 25th.Therefore,it is recommended that in the nursery and transplanting of rapeseed carpet seedlings,half-dose uniconazole seed dressing,a seeder parameter of 70 gears,full-substrate nursery,and mechanical transplanting in late October be adopted to achieve robust seedlings,increase rapeseed yield,and facilitate the rotation with late-maturing rice.