Little is known about the rate of mineralisation of chicory (Cichorium intybus) residues and how this may influence the availability of nitrogen (N) for subsequent crops. An incubation study was conducted to compare the relative rates of N mineralisation and carbon dioxide production from different plant fractions of chicory and lucerne (Medicago sativa) over 112 days. Plants were separated into leaves, stems, fibrous roots (<1 mm), and taproots (>4 mm), which were either ground or segmented, and then mixed with soil in sealed jars. Results showed that net N mineralisation occurred from day 7 for lucerne leaves, but not until day 56 for chicory leaves. By day 112, chicory leaves only produced approximately 25% of the N mineralised by lucerne leaves. Segmented chicory taproots released 32% and 24% more of the plant N and carbon (C), respectively, than any other chicory and lucerne plant fractions despite having a C:N ratio greater than 30. The presence of a common fungal saprophyte (Rhizopus spp.) in the segmented chicory taproot treatments appeared to accelerate the net N mineralisation rate. Whilst coarse chicory roots released mineral N relatively rapidly, the lower N content observed in the chicory plant residues limited the capacity of chicory to release the same quantity of mineral N compared to lucerne. Chicory needs to be grown with a companion legume so that N mineralisation of the residues better matches the demands of N requirement for the following non-legume cropping phase.

中文翻译：

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菊苣和苜蓿氮矿化模式比较

关于菊苣 ( Cichorium intybus ) 残留物的矿化率以及这如何影响后续作物的氮 (N) 利用率，人们知之甚少。进行了一项孵化研究，以比较112 天内菊苣和苜蓿 ( Medicago sativa )不同植物部分的氮矿化和二氧化碳产生的相对速率。将植物分成叶、茎、须根（<1毫米）和主根（>4毫米），将其磨碎或分段，然后在密封罐中与土壤混合。结果表明，苜蓿叶从第 7 天开始出现净氮矿化，但菊苣叶直到第 56 天才出现净氮矿化。到第 112 天，菊苣叶仅产生苜蓿叶矿化氮的约 25%。尽管 C:N 比率大于 30，但分段菊苣主根比任何其他菊苣和紫花苜蓿植物部分分别释放多 32% 和 24% 的植物氮和碳 (C)。 存在常见的真菌腐生菌（根霉） spp.）在分段菊苣主根处理中似乎加速了净氮矿化速率。虽然粗菊苣根相对较快地释放矿物质氮，但在菊苣植物残留物中观察到的较低氮含量限制了菊苣与紫花苜蓿相比释放相同量矿物质氮的能力。菊苣需要与伴生豆科植物一起种植，以便残留物的氮矿化更好地满足接下来的非豆科作物种植阶段的氮素需求。