太原城郊老菜区番茄氮肥利用率及氮去向研究

为了加强太原城郊老菜区蔬菜生产中氮素管理和降低蔬菜生产对环境的污染,在田间采用微区15N示踪法研究了番茄生产过程中农民习惯施氮(FAR)和推荐施氮(RAR)的氮肥利用效率和氮去向。结果表明:与习惯施氮比较,推荐施氮对番茄各部位干物质量、氮浓度和产量均无显著影响,且明显降低了番茄地上部吸收化学肥料氮的百分率,但对各部位氮肥利用效率和总氮肥利用效率无显著影响,氮肥利用效率仅为8%～9%,这可能与土壤原来氮库或所施有机肥矿化提供了大量氮素有关。两种施肥处理均导致65%左右的氮素损失,其中习惯施氮和推荐施氮分别导致30%和26%的氮素淋洗到40cm以下土层,为此有必要种植蔬菜后利用深根系粮食作物吸收土壤下层氮素来降低蔬菜生产对环境的影响。

Use efficiency and fate of applied nitrogen in long-term tomato districts of Taiyuan

n order to manage N efficiently in long-term vegetable production districts, field trials were conducted to determine nitrogen use efficiency (NUE) and the fate of N under 2 nitrogen fertilizer application rates [farmer application rate (FAR) and recommended application rate (RAR) of ¹⁵N] during tomato cultivation. The results indicate that RAR does not significantly influence dry-matter of different parts, yield and nitrogen content of tomato, compared with FAR. Contrary to FAR, RAR results in lower percent of plant nitrogen derived from fertilizer (NDF). The 2 treatments yield similar NUE, which is 8%~9%. This may be due to either relative large nitrogen pool in soils, high manure application or both. 65% of the nitrogen supplied as inorganic fertilizer is lost under two treatments, and 30% under FAR and 26% under RAR of which leaches to depths over 40 cm of soil profile. It is therefore necessary to understand whether leached nitrogen is utilizable by deep-rooted crops.