施氮、钾和钼对菠菜不同生长阶段硝态氮积累影响研究初报

Effects of N, K and Mo application on the nitrate accumulation at different growth stages of spinach

采用盆栽试验研究了肥料(氮、钾、钼)互作对菠菜不同生长阶段硝态氮积累的影响。结果表明,施肥对菠菜硝态氮积累的影响整体表现为:柄>叶,老叶>新叶;与生长前期相比,收获期各部位中硝态氮含量均有下降趋势。不施氮条件下,施钼极显著或显著地降低了菠菜生长前期和收获期叶片中硝态氮含量,降幅分别为19 3%和21 4%;施氮条件下,施钼仅显著降低了菠菜生长前期叶片中硝态氮含量,降幅达21 2%。在本试验条件下,单施钼比钼钾配施更有利于降低菠菜叶片中硝态氮的含量;钾与钼营养的相互效应,以及钾与钼之间如何平衡,似乎是影响施钼效果的关键。

Application of chemical fertilizer, especially over-fertilization, conduced to the accumulation of nitrate nitrogen easily in the leaves and petioles of spinach . Literatures reported that K and Mo application could improve NRase activity of leaf which resulted in the reduction of nitrate content. However, the interactive effects of Mo and K on the accumulation of nitrate nitrogen in vegetables, and how to balance application of Mo and K was little known. Whereas, pot culture experiment was conducted to study the effects of fertilization (N, K and Mo combined application) on contents of nitrate nitrogen in the leaves and petioles at different growth stage of spinach. The objective of this study is exploring the optimal condition under which nitrate content decreased with Mo application. The results showed that the nitrate contents differed with positions. Nitrate content in petioles is the highest, followed with old leaves and young leaves. Compared with growing prophase of spinach, the contents of nitrate nitrogen in different position trended to decrease at harvest. Without the nitrogen application, the nitrate contents in spinach leaves were dramatically decreased by Mo application. The decreasing amplitudes were 19.3% at growth prophase and 21.4% at harvest, respectively. With the nitrogen application, the nitrate nitrogen contents in spinach leaves were only dramatically decreased by Mo application at growth prophase,the (decreasing) amplitude was 21.2%. However, Mo or K application could not significantly decrease the contents of (nitrate) (nitrogen) in spinach petioles. Single Mo application is more propitious to decrease the nitrate nitrogen contents in spinach leaves than Mo and K combined application. The interaction of Mo and K and how to balance fertilization maybe is key point which influence the effects of Mo application.