不同水氮水平对马铃薯产量和水氮利用效率的影响

为了给马铃薯生产提供科学合理的水氮管理依据,以品种"大西洋"脱毒组培苗为材料,通过3个水分水平(90%,70%和50%的土壤田间持水量)和3个氮肥水平(不施氮,施N 0.2 g·kg~(-1),施N 0.4 g·kg~(-1))完全组合的盆栽试验研究了不同水氮水平对马铃薯产量和水氮利用效率的影响。结果显示:在同一水分水平下,中氮处理的块茎产量、整株生物量和水氮利用效率明显高于低氮和高氮处理;在同一施氮量下,随着土壤含水量的增加,马铃薯的块茎产量、整株生物量和氮肥利用率明显提高。在9种水氮组合方式下,正常水分和中氮处理下的块茎产量、整株生物量、氮肥农学利用率和氮肥偏生产力最高,分别为273 g·株~(-1)、359 g·株~(-1)、52.5 g·g~(-1)和143.9 g·g~(-1)。这说明90%的田间持水量和0.2 g·kg~(-1)土有利于马铃薯植株获得较高的产量和水氮利用效率。此外,中氮下较高的整株生物量和较低的收获指数说明:适量施用氮肥增加产量主要是因为其增加了整个植株同化物的积累,而非增加了同化物向块茎的分配。

Effects of different water and nitrogen levels on tuber yield, water and nitrogen use efficiency of potato

Using virus-free plantlets of potato (cultivar Atlantic),a pot experiment with three soil water levels (90％,70％ and 50％ of field capacity) and three nitrogen fertilizer levels (0,0.2,0.4 g·kg-1) was conducted to study the effect of different water and nitrogen levels on tuber yield,water and nitrogen use efficiency of potato in order to provide information for better management of water and nitrogen in potato production.The results showed that,under the same water level,potato tuber yield,biomass,water and nitrogen use efficiency under moderate nitrogen were higher than those of low and high nitrogen.Under the same nitrogen level,potato tuber yield,bionass and nitrogen use efficiency all increased with the increase of soil water content.Among the nine treatments,tuber yield,biomass,nitrogen agronomic efficiency and partial factor productivity under well-watered and moderate nitrogen condition were the highest,and their values were 273 g· plant-1、359 g· plant-1 、52.5 g· g-1 and 143.9 g· g-1,respectively.It suggests that 90％ of field capacity and 0.2 g· kg-1 soil was helpful to higher yield and use efficiency of water and nitrogen.In addition,higher biomass and lower harvest index under moderate nitrogen suggest that moderate nitrogen increase yield mainly through increasing the accumulation of assimilates in plant,but not increasing the allocation of assimilates to tuber.