On farms with intensive animal production, manure represents a significant source of nitrogen (N) in crop production. Cattle deep litter is a common manure type in Denmark due to concerns regarding animal welfare. With a low ammonium to total N ratio, large quantities of deep litter are needed to meet crop N requirements. However, documentation regarding the N fertilizer value of deep litter and its effects on nitrate leaching losses needs further scrutiny. We investigated the N fertilizer effect of cattle deep litter in the year of amendment and in two residual years, and determined nitrate leaching losses in the two seasons following amendment, both with and without use of a cover crop.

Spring barley (Hordeum vulgare) grew in outdoor lysimeters (1 m² and 1.5 m deep) with two soil types, a loamy sand and a sandy loam. Crop N uptake was measured after incorporation of two rates of deep litter (362 and 725 kg total N ha⁻¹), and compared with uptakes following mineral N fertilizer. After harvest, the lysimeters were vegetation-free or established with a cover crop (fodder radish, Raphanus sativus). The residual effect of the treatments was monitored in two following seasons.

In the year of amendment (2017), crop yields in deep litter amended lysimeters were similar to those obtained with mineral N fertilizer on sandy loam while yields were lower on loamy sand. The N effect of the deep litter equaled its ammonium content on the loamy sand while it was higher on the sandy loam. The corresponding N fertilizer replacement value (NFRV) of manure total N was 9.7% and 16.2%. In the first residual year (2018), NFRV of the deep litter was 9.5% on the loamy sand and 6.8% on the sandy loam. The third year (2019) effect was small on both soils. In the first autumn-winter, marginal nitrate leaching of N was unaffected by type of amendment. It equaled 8.1% of total N applied when lysimeters were without a cover crop and 1.4% with a cover crop. In the second leaching season, marginal nitrate leaching was 4.6% of total N applied in the previous year.

We conclude that deep litter can supply spring barley with sufficient N for optimal growth and has a considerable residual effect in the year after amendment. Marginal nitrate leaching was unaffected by N source and soil type, and nitrate leaching losses can be effectively reduced by introducing a cover crop.

在动物生产密集的农场，粪便是作物生产中氮的重要来源。由于对动物福利的关注，牛深垫料是丹麦常见的肥料类型。由于铵态氮与总氮的比率低，因此需要大量深垫料才能满足作物对氮的需求。但是，有关深垫料氮肥价值及其对硝酸盐淋失损失的影响的文献需要进一步审查。我们调查了改种年份和两个剩余年份中牛深垫料的氮肥效应，并确定了改种后两个季节中是否使用覆盖作物的硝酸盐浸失。

春季大麦（大麦（Hordeum vulgare））生长在具有两种土壤类型（壤土和壤土）的室外测渗仪中（深度分别为1 m ²和1.5 m）。在掺入两个深垫料（总N ha ^-1和362 kg 725 kg ）后，测量了作物的N吸收量，并将其与矿质N肥料后的吸收量进行了比较。收获后，测力计是无植被的或用覆盖作物（饲料萝卜，Raphanus sativus）建立的。在接下来的两个季节中监测治疗的残留效果。

在修订年度（2017年），深垫改良蒸渗仪上的作物产量与砂壤土上使用矿物氮肥的产量相似，而在砂壤土上的产量较低。深垫料的氮效应等于在壤土沙上的铵含量，而在壤土沙上则更高。粪肥总氮的相应氮肥替代值（NFRV）为9.7％和16.2％。在第一个剩余年份（2018年），深壤土的NFRV在壤土沙上为9.5％，在沙壤土上为6.8％。第三年（2019年）对两种土壤的影响均很小。在第一个秋冬，氮的边际硝酸盐浸出不受修正类型的影响。当测湿仪没有遮盖作物时，它等于施用的氮总量的8.1％，而有遮盖作物时则为1.4％。在第二个浸出季节，边际硝酸盐浸出为4。

我们得出的结论是，深垫料可以为春季大麦提供充足的N，以实现最佳生长，并且在改良后的一年中具有相当大的残留效应。边际硝态氮的淋溶不受氮源和土壤类型的影响，通过引入地被作物可以有效减少硝酸盐的淋溶损失。