Nitrate supply affects root growth differentially in two rice cultivars differing in nitrogen use efficiency |
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Authors: | Wenjing Song Kousar Makeen Dongsheng Wang Chenming Zhang Yehong Xu Haijuan Zhao Erdi Tu Yali Zhang Qirong Shen Guohua Xu |
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Affiliation: | 1. Land Dynamics Group, Wageningen University, PO Box?47, 6700, AA, Wageningen, The Netherlands 2. Biological Farming Systems Group, Wageningen University, PO Box?563, 6700, AN, Wageningen, The Netherlands
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Abstract: | Peatland soils contain large amounts of nitrogen (N) in the soil and mineralization can contribute substantially to the annual mineral N supply of grasslands. We investigated the contribution of N mineralization from peat with respect to the total annual N uptake on grasslands with anthropogenic A horizons and submerged tile drains. The study included i) a pot experiment to determine potential N mineralization from the topsoil and the subsoil, ii) a 1-year field experiment to study herbage yields and N uptake under fertilized and non-fertilized conditions and iii) a 3-year field study where herbage yield and N uptake from the top 30 cm and the entire soil profile were monitored. The 3-year field study yielded an average N uptake of 342 kg?ha?1 under non-fertilized conditions but the contribution of subsoil peat N mineralization to the total N uptake was found to be negligible. Our calculations demonstrate that peat N mineralization contributed only 10% to 30% to the total N-uptake, mainly coming from the top 30 cm. Most of the N uptake under unfertilized conditions appears to be largely the result of mineralization from long-term inputs of dung, ditch sludge, farmyard manure, cow slurry and non-harvested herbage. |
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