Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates
Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates
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DOI：
10.1007/s10705-017-9875-5
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发表时间：
2018-01-01
影响因子：
3.1
通讯作者：
van Ittersum, M. K.
中科院分区：
文献类型：
--
作者：
Hijbeek, R.;ten Berge, H. F. M.;van Ittersum, M. K.
有机改进剂[如农家肥（FYM）、泥浆或作物残留物]对作物的氮(N)供应通常表示在改进剂的氮肥替代价值（NFRV）中。NFRV的值可以通过与只施用矿物肥的地块进行作物产量或氮素吸收的比较来确定。NFRV则被定义为在获得相同作物产量的情况下，使用有机改进剂N节省的矿物肥料N量（kg/kg）。已知影响NFRV的因素有栽培作物类型、土壤类型、施肥历史和方法或施用时间。我们调查了长期NFRV是否取决于施氮量。利用欧洲8个长期试验的数据，比较了全氮供给低和全氮供给高时的NFRV值。我们的研究结果表明，高总氮供给时FYM的NFRV值显著高于低总氮供给时（1.12 vs. 0.53, p = 0.04）。对于所调查的其他修正类型，高总氮供给时NFRV也高于低总氮供给时，但样本量太小或变化太大，无法检测到显著差异。欧洲农民通常以高施氮量耕作。如果肥料的补充是基于在低总氮供应下估计的粪肥的NFRV，则氮肥需要量可能被高估。这可能导致氮素的过度利用，降低氮素利用效率，增加氮素对环境的损失。
Nitrogen (N) supply from organic amendments [such as farmyard manure (FYM), slurries or crop residues] to crops is commonly expressed in the amendment's Nitrogen Fertiliser Replacement Value (NFRV). Values for NFRV can be determined by comparison of crop yield or N uptake in amended plots against mineral fertiliser-only plots. NFRV is then defined as the amount of mineral fertiliser N saved when using organic amendment-N (kg/kg), while attaining the same crop yield. Factors known to affect NFRV are crop type cultivated, soil type, manuring history and method or time of application. We investigated whether long-term NFRV depends on N application rates. Using data from eight long term experiments in Europe, values of NFRV at low total N supply were compared with values of NFRV at high total N supply. Our findings show that FYM has a significant higher NFRV value at high total N supply than at low total N supply (1.12 vs. 0.53, p = 0.04). For the other amendment types investigated, NFRV was also higher at high total N supply than at low total N supply, but sample sizes were too small or variations too large to detect significant differences. Farmers in Europe usually operate at high rates of total N applied. If fertiliser supplements are based on NFRV of the manure estimated at low total N supply, N fertiliser requirements might be overestimated. This might lead to overuse of N, lower N use efficiency and larger losses of N to the environment.