减氮及有机替代对马铃薯根系形态和产量的影响

田间研究减氮及有机肥替代对半干旱区膜下滴灌马铃薯不同发育时期根系生长的影响,并讨论其与产量形成的关系,为马铃薯高产高效栽培提供理论和技术依据。试验以青薯9号为试验材料,以常规施化学氮肥225 kg·hm^-2为对照(CK),设置两个减氮处理施70%化学氮肥(RN)和施50%化学氮肥(LN),以及两个有机肥替代处理80%化学氮肥+20%有机氮肥(LO)和60%化学氮肥+40%有机氮肥(HO)。结果表明,与对照相比,RN处理单株结薯数、中薯率和小薯率均未显著变化,大薯率下降0.32百分点,减产10.93%,HO处理单株结薯数增加了11.77%,大薯率和中薯率分别增加0.43和6.47百分点,增产19.01%。同时,HO处理较对照显著(P<0.05)增加了块茎形成期根长、根投影面积、根体积、根尖数和根分叉数,以及块茎膨大期根尖数。相关性分析表明,产量与苗期、块茎膨大期、淀粉形成期根长,及块茎膨大期根表面积、根体积、根尖数、根分叉数均呈极显著(P<0.01)正相关。因此,以90 kg·hm^-2有机氮和81 kg·hm^-2

Effects of reduced chemical nitrogen and organic manure substitution on potato root morphology and yield

Field experiments were conducted to study the effects of reduced chemical nitrogen and organic manure substitution on root growth in different developmental stages and yield of potato in the semi-arid area under film drip irrigation, in order to provide an efficient nitrogen management method in the cultivation of potato. Potato cultivar Qingshu9 was used in the test. The conventional N rate of 225 kg·hm^-2 was used as the control (CK), 70% chemical nitrogen fertilizer (RN) and 50% chemical nitrogen fertilizer (LN) were set up for reduced chemical nitrogen application treatments, and 80% chemical nitrogen fertilizer+20% organic nitrogen manure (LO) and 60% chemical nitrogen fertilizer+40% organic nitrogen manure (HO) were set up for organic manure substitution application treatments. The results showed that compared with CK, the number of tuber per plant, medium tuber rate and small tuber rate did not change significantly under RN treatment, however, the large tuber rate was decreased by 0.32 percent points and the yield were decreased by 10.93%. The number of tuber per plant were increased by 11.77%, the large tuber rate and medium tuber rate were increased by 0.43 and 6.47 percent points under HO treatment, respectively, and the yield was increased by 19.01%. The potato root under HO treatment had longer root length, larger projected root area, root volume, more tips and forks during the tuber initiation stage, and more tips during the tuber bulking stage compared with CK. The yield was significantly (P<0.01) positively related to the root length during the seedling, tuber bulking and starch formation stage, and the root surface area, the root volume, the number of tips and the number of forks during the tuber bulking stage. Therefore, 90 kg·hm^-2 organic nitrogen and 81 kg·hm^-2 chemical nitrogen as base fertilizers, and 54 kg·hm^-2 chemical nitrogen as topdressing in the tuber formation stage could improve the root growth effectively, promote the formation of effective tuber during the early growth stage, increase the number of tuber per plant and the expansion of tubers, and thus produce a higher yield of potato.