氮肥分期运筹对套作甘薯产量、品质及氮素效率的影响

为了探寻套作甘薯高产优质的氮肥运筹方式, 以甘薯套作及单作为主区, 定量氮肥全部基施、分2期和分3期运筹为副区, 于2015—2016两年度探讨了不同处理对2个甘薯品种(渝紫7号和万薯10号)块根产量、品质及氮肥利用效率的影响。结果表明, 2个品种无论单作或套作, 定量氮肥分2期或分3期运筹显著提高甘薯块根产量、单薯重、可溶性蛋白含量、可溶性糖含量、氮肥表观利用率和氮肥偏生产力; 套作中定量氮肥不同运筹方式对2个甘薯品种商品薯率影响不显著, 但单作中分3期运筹时最高; 万薯10号块根β-胡萝卜素含量以定量氮肥分3期运筹最高, 渝紫7号块根花青素含量以分2期和3期运筹最高, 2个品种块根淀粉含量以氮肥全部基施最高。套作降低了除甘薯块根可溶性糖含量外的其他营养品质以及产量和氮肥利用效率, 但套作定量氮肥分2期或3期运筹, 可使这些指标达到或优于单作氮肥全部基施水平。为提高块根淀粉含量, 定量的氮肥宜采用全部基施, 为同时优化其他营养品质、提高甘薯产量和氮肥利用效率, 定量的氮肥宜采用分2期或分3期运筹。

Effects of Split Application of Nitrogen Fertilizer on Yield,Quality and Nitrogen Use Efficiency of Sweet Potato

To explore the optimal split nitrogen fertilizer application methods for high yield and quality sweet potato production in intercropping, we conducted a field experiment using two sweet potato cultivars Yuzi 7 and Wanshu 10 with single N application, 2-split and 3-split N application, and measured the yield, quality, and nitrogen use efficiency in monocropping and interplanting in 2015-2016. The yield, single storage root weight, soluble protein content, soluble sugar content of storage root, apparent nitrogen use efficiency and partial nitrogen productivity were significantly increased in the two tested cultivars under 2-split and 3-split N application in monocropping and interplanting. Under interplanting, commodity rate was not significantly different in the two cultivars among the three N application treatments, however, the highest commodity rate was obtained under 3-split N application in monocropping. The highest content of β-carotene in the storage root was obtained when 3-split N application was used in Wanshu 10, and the highest content of anthocyanin in the storage root was obtained when 2-split N application was used in Yuzi 7, but the highest starch content of storage root was obtained when non-split N application was used in the two cultivars. All of the quality traits except soluble protein content of storage root, and yield and nitrogen use efficiency reduced in intercropping, but these traits were equal or better in 2 or 3-split N application when compared to those in monocropping. In conclusion, non-split N application could be used to increase the starch content of storage root, and 2 or 3-split N application could be used to increase other quality traits, yield and nitrogen efficiency of sweet potato.