不同水氮条件对日光温室冬春茬黄瓜栽培氨挥发的影响

Effects of irrigation and nitrogen application on ammonia volatilization in solar greenhouse soils in winter-spring cucumber cultivation

通过设置不同灌水、施氮处理,采用通气法研究了温室土壤施肥带与非施肥带的氨挥发特征,探讨了节水灌溉、减量施氮处理与传统水氮处理土壤氨挥发的差异及其影响因素。结果表明,冬春季温室黄瓜土壤在氮肥基施7 d后出现氨挥发峰值,减施氮25%处理的氨挥发峰值比传统施氮处理降低18.2%~34.3%;追肥后,施肥带和非施肥带的氨挥发速率峰值分别在第1 d和第5 d出现,减施氮25%处理与传统施氮处理相比,氨挥发速率峰值降低12.3%~37.2%;节水灌溉处理与传统灌水处理相比,氨挥发峰值则提高3.9%~47.0%。土壤中铵态氮含量以及温度的升高可促进土壤的氨挥发,而土壤含水量则与氨挥发速率呈负相关。在黄瓜花期和初瓜期,施肥带的累计氨挥发量显著高于非施肥带,而初瓜期之后,施肥带与非施肥带的氨挥发无显著差异。整个黄瓜生育季的累计氨挥发量为11.4~26.6 kg.hm 2;与传统施氮和灌水处理相比,减施氮25%处理的累计氨挥发量可降低20.8%~22.2%,但节水灌溉处理的累计氨挥发量却有所增加,增加幅度为0~4.51%。适宜减少灌水和氮肥用量不会降低黄瓜产量,且可大幅度提高灌水和氮肥利用效率。

Ammonia volatilization characteristics in fertilized and non-fertilized belts of greenhouse soils were investigated under different irrigation and nitrogen application treatments during winter-spring cucumber cultivation via the venting method.Also differences in ammonia volatilization among water-saving irrigation,reduced nitrogen treatment and traditional water/nitrogen treatments were analyzed and discussed.From the study,peak ammonia volatilization rate was on 7 days after basal fertilization in the solar greenhouse soil.Compared with traditional nitrogen treatment,the peak value for 25%-reduction in nitrogen fertilization dropped by 18.2%~34.3%.While peak ammonia volatilization rate was on the first day in the fertilization belt,it was on the fifth day in the non-fertilization belt after topdressing.Also compared with traditional treatments,the peak value for 25%-reduction in nitrogen fertilization also dropped by 12.3%~37.2% and that for water-saving irrigation treatment increased by 3.9%~47.0%.Ammonia volatilization and loss in the fertilization belt of greenhouse soils mainly occurred during cucumber blooming and initial fruiting periods,which were respectively 1.07~1.50 and 1.06~1.27 times those of the non-fertilization belt.No significant differences in ammonia volatilization and loss existed between fertilization and non-fertilization belts of greenhouse soils during cucumber full-fruit period and end-fruit periods.Ammonia volatilization rate increased with（0~10 cm） soil ammonium nitrogen content and improvement in（5 cm） soil temperature.However,a negative correlation existed between（0~10 cm） soil water content and ammonia volatilization rate.Cumulative ammonia volatilization was 11.4~26.6 kg.hm 2 during the entire cucumber growth season.Compared with traditional nitrogen and irrigation treatments,cumulative ammonia volatilization in the 25%-reduction in nitrogen fertilization dropped by 20.8%~22.2%.Also water-saving irrigation treatments concurrently improved cumulative ammonia volatilization by 0~4.51%.The analysis showed that appropriate reductions in nitrogen fertilization significantly limited ammonia volatilization and enhanced irrigation/nitrogen fertilizer efficiency in solar greenhouse soils in Hebei Province.While water-saving also significantly improved irrigation/nitrogen fertilizer efficiency,it failed to significantly reduce ammonia volatilization.Irrigation water-use efficiency of the 25%-reduction in nitrogen fertilization improved by 2.6%~5.9% over traditional nitrogen treatment.Compared with traditional irrigation,agronomic efficiency of nitrogen in water-saving irrigation increased by 13.9%~75.0%.