Abstract: To explore the effects of different rates of N, P2O5, and K2O fertilizers on yields and water-fertilizer use efficiency, taking a tartary buckwheat \[Fagopyrum tataricum (L.) Gaertn.\] cultivar Yunqiao 2 as experimental materials, this paper investigated the changes of tartary buckwheat biomass, yield, harvest index (HI), soil water storage in 0~300 cm soil layers, water consumption, water use efficiency (WUE), fertilizer use efficiency and fallow efficiency, and analyzed the effects of fertilizer application rates on the yield  water and fertilizer efficiency. The results showed that: yield and biomass were highest at low fertilizer rate (LF), with an  increase of yield by 1.1%~30.5%, and an  increase of biomass by 1.1%~19.4%. In 2015 and 2016, the order of the precipitation use efficiency (PUE) in the growth period, the PUE in the fallow period and the annual precipitation use efficiency were as follows: low fertilizer rate (LF)> no fertilization (CK) > medium fertilizer rate (MF) > and high fertilizer rate(HF), but  LF> MF>CK>HF during 2017, respectively. WUE was highest with LF treatment compared to the other treatments in 2015 and 2017. In the three consecutive years, the order of fertilizer agronomic efficiency (AE), and partial factor productivity was LF>MF>HF. Overall, under the current experimental condition, LF treatment increased tartary buckwheat yield, biomass, WUE, as well as HI. At the meantime, AE and PFP were significantly increased by LF, compared to MF and HF, respectively. Also, LF was able to regulate soil water storage in fallow periods according to different precipitation years and water consumption, enhance soil moisture recovery in fallow periods, and improve fallow efficiency, as well as PUE. The results provided a theoretical basis for reasonable fertilizer rates in the cultivation of hole-sown tartary buckwheat with whole film mulching in semiarid area.

Key words: tartary buckwheat, whole field soil-plastic mulching, fertilization, water use efficiency, fertilizer use efficiency

摘要： 为探明不同氮、磷、钾肥配比对全膜覆土穴播苦荞产量和水肥利用率的影响，以云荞2号为试验材料，研究在不同施肥量配比条件下，苦荞生物量、产量、收获指数、0~300 cm土层土壤贮水量、耗水量、水分利用效率、肥料利用效率、休闲效率等指标的变化，分析施肥量对产量及水肥利用效率的影响。结果表明：2015—2017年，低量施肥处理产量和生物量均表现为最高，产量增加1.1%~30.5%、生物量增加1.1%~194%。2015和2016年生育期降水利用效率、休闲期降水利用效率和年降水利用效率表现为低量施肥>不施肥>中量施肥>高量施肥，2017年表现为低量施肥>中量施肥>不施肥>高量施肥。2015和2017年水分利用效率表现为低量施肥最高，3年肥料农学效率和肥料偏生产力均表现为低量施肥>中量施肥>高量施肥。综上，低量施肥处理能够增加苦荞产量和生物量，提高水分利用效率和收获指数，明显增加肥料农学效率和肥料偏生产力，且低量施肥处理能够根据降水年型及生育期内耗水量的高低调控休闲期土壤水分，增强休闲期土壤水分恢复力，提高休闲效率和降水利用效率。研究结果可为半干旱区旱地全膜覆土穴播苦荞栽培中合理施肥提供理论依据。

关键词: 苦荞, 全膜覆土穴播, 施肥, 水分利用效率, 肥料利用效率