Improving nitrogen management on grassland on commercial pilot dairy farms in the Netherlands
Improving nitrogen management on grassland on commercial pilot dairy farms in the Netherlands
复制标题
改善荷兰商业试点奶牛场草地氮管理
DOI：
10.1016/j.agee.2012.08.012
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
H. Keulen
中科院分区：
文献类型：
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作者：
J. Oenema;M. Ittersum;H. Keulen
在草地高放牧密度和高氮投入的奶牛养殖场，氮素利用效率(N输出与N输入的比率)较低，导致环境中的氮损失较大。本研究描述和分析了“奶牛和机会”项目(C&O)中16个商业试点奶牛场在12年(1998-2009年)期间草地氮素管理的发展和变化，目的是将这一知识应用于其他农民，以期对改善管理的可能性提供洞察力。牧场产奶量为11~23Mgha−1，草地约占土地总面积的80%(63~97%)。试验农场草地(粪肥、化肥、放牧粪便、生物固氮和大气沉降)的平均施氮量(kgtalnha−1年期−1)从1998年的540降至2001年的450，而其余时间的年际变化很小(在400~450之间)。草地平均干物质产量(11Mgha−1)在不同年份和不同农场(7.7Mgha−1和16Mgha Gha 1之间)不同，没有明显的时间趋势。在施氮量为600kgha−1左右的草地上，我们没有观察到农场规模上干物质产量递减的趋势，这是因为高生产强度的农场(−1)比低生产强度的农场需要更多的干物质，并且能够在高氮素投入水平的草地上加强氮素管理。提高氮肥利用率的管理办法包括减少放牧时间，从而提高干物质产量和氮肥利用率，这是更好地利用有机肥的结果。
Nitrogen (N) use efficiency (NUE), the ratio of N output and N input, is rather low on dairy farms with high stocking densities and high N input on grassland resulting in high N losses to the environment. This study describes and analyses the development and variation in N management on grassland on 16 commercial pilot dairy farms in the project ‘Cows & Opportunities’ (C&O) over a 12-year period (1998–2009, with the aim that applying this knowledge to other farmers may provide insight in the (im)possibilities to improve management. Farm milk production ranged from 11 to 23Mgha−1and grassland occupied ca. 80% of the total land area (between 63 and 97%). Mean N application rate (kgtotalNha−1year−1) on grassland (in manure, chemical fertilizer, excreta during grazing, biological N fixation and atmospheric deposition) on the pilot farms decreased from 540 in 1998 to 450 in 2001, while in the remainder of the period the inter-annual variation was low (between 400 and 450). Mean dry matter yields on grassland (11Mgha−1) varied among years and farms (between 7.7 and 16Mgha−1), without any significant temporal trend. We observed no trend of diminishing returns of dry matter yields at farm scale up to an N application rate on grassland of ca. 600kgha−1because farms with a high production intensity (Mgmilkha−1) need more dry matter than farms with a lower intensity and were able to increase nitrogen management on grassland with high N input levels. Management options that result in improved NUE include reduced grazing time which results in increased dry matter yields and NUE as a consequence of better utilization of organic manure.