注肥时间对花椰菜产量、品质和水氮利用效率的影响

The Timing of Application of Nitrogen in Drip Fertigation Affects Yield,Quality,as Well as Water and Nitrogen Use Efficiency of Cauliflower

针对我国设施蔬菜水肥管理粗放、肥料利用效率低等突出问题,通过温室花椰菜小区试验,设置4种注肥时间处理,即T1(1/5N-4/5W)、T2(1/5W-1/5N-3/5W)、T3(2/5W-1/5N-2/5W)、T4(3/5W-1/5N-1/5W)(1/5W-1/5N-3/5W表示整个灌水过程的前1/5时间灌水,接下来的1/5时间施肥,后3/5时间灌水冲洗管道,其他同),研究了不同注肥时间对温室花椰菜产量、品质、水氮利用效率和土壤剖面氮素迁移规律的影响,探索了滴灌施肥条件下最优注肥时间及其调控阈值。结果表明,花椰菜全生育期耗水量随着注肥时间向后推移而呈先增加后减少趋势,其中T3处理耗水量最高,为135.26 mm。在灌溉施肥过程中向后推移施肥可显著提高花椰菜产量和品质,其中后期施肥处理(T3、T4)的产量较前期施肥处理(T1、T2)增加了1.78%~6.39%。花椰菜的氮肥利用效率和氮肥回收率随着注肥时间的向后推移而呈逐渐增加趋势,且花球部位的氮素累积量明显增加,水分利用效率显著降低。另外,向后推移注肥时间有效地减少了硝态氮的淋失。在试验条件下,综合考虑花椰菜产量、品质和水氮利用效率,灌溉施肥过程中注肥时间应尽量向后推移。

Increasing nitrogen use efficiency in producing vegetables from greenhousesis essential in China, and in this paper, we investigated the impact of the timing of fertigation on yield, quality, water and nitrogen use efficiency of cauliflower using plot experiments. Four fertigation timings were examined： 1/5N-4/5W （T1）, 1/5W-1/5N-3/5W （T2）, 2/5W-1/5N-2/5W （T3）, 3/5W-1/5N-1/5W （T4）, in which 1/5W, 1/5N and 3/5W represent- ed irrigating water at the first fifth of a irrigation/fertigation event, applying the nitrogen at the second fifth of the event, flashing the irrigation pipe in the last three fifths of the event, respectively. The results showed that the total water consumption increased first and then decreased as the fertigation was delayed, peaking in T3 with a water consumption of 135.26 mm. The timing of the fertigation had a significant effect on yield and quality, with the yield increasing by slightly delaying the nitrogen application. Applying the nitrogen in the late stage （T3 and T4） increased the yield by 1.78%-6.39%, compared with application at the beginning stage （T1 and T2）. Water use efficiency, nitrogen use efficiency and recovery efficiency, as well as the percentage of nitro- gen in the ball-flower all increased by delaying the nitrogen application to later stage. Delaying the nitrogen ap- plication also reduced nitrate leaching. In summary, our experimental results showed that delaying nitrogen ap- plication in fertigation increased yield, quality, water and nitrogen use efficiencies.