Nitrogen and Phosphorus Use Efficiencies in Dairy Production in China
Nitrogen and Phosphorus Use Efficiencies in Dairy Production in China
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DOI：
10.2134/jeq2012.0464
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发表时间：
2013-07-01
影响因子：
2.4
通讯作者：
Zhang, F. S.
中科院分区：
文献类型：
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作者：
Bai, Z. H.;Ma, L.;Zhang, F. S.
近年来，中国的牛奶产量大幅增加，这对氮和磷的循环产生了重大影响。然而，不断变化的乳制品生产系统内的营养流动并没有很好地量化。本研究的目的是通过数据库开发和模拟建模，增加对奶牛生产中氮、磷循环和利用的定量认识。2010年，在整个1987年和34.6万吨（Gg）的N和P输入中，只有188 Gg N和31 Gg P最终进入了牛奶。在整个系统水平上，氮和磷的平均利用效率分别为24%和25%。四种乳制品系统之间的效率差异显著。这些系统的N损失通过NH3挥发（33%）、排放（27%）、反硝化（24%）、NO3浸出和径流（16%）以及N2O排放（1%）发生。工业饲养场比传统饲养场每公斤牛奶使用更少的饲料，并且更多地依赖于来自肥沃农田的优质饲料；他们很少将肥料养分循环到农田。随着工业饲养场系统的蓬勃发展，畜群水平的总体平均氮和磷利用效率将提高，但整个乳制品生产系统水平的平均氮和磷利用效率将下降，除非通过重新连接中国的饲料和乳制品生产部门来更有效地利用粪肥氮和磷。
Milk production has greatly increased in China recently, with significant impacts on the cycling of nitrogen (N) and phosphorus (P). However, nutrient flows within the changing dairy production system are not well quantified. The aim of this study was to increase the quantitative understanding of N and P cycling and utilization in dairy production through database development and simulation modeling. In 2010, of the entire 1987 and 346 thousand tons (Gg) of N and P input, only 188 Gg N and 31 Gg P ended up in milk. The average N and P use efficiencies were 24 and 25%, respectively, at the whole system level. Efficiencies differed significantly between the four dairy systems. Losses of N from these systems occurred via NH3 volatilization (33%), discharge (27%), denitrification (24%), NO3 leaching and runoff (16%), and N2O emission (1%). Industrial feedlots use less feed per kg milk produced than traditional systems, and rely more on high-quality feed from fertilized cropland; they have very poor recycling of manure nutrients to cropland. As industrial feedlot systems are booming, overall mean N and P use efficiencies will increase at herd level but will decrease at the whole dairy production system level unless manure N and P are used more efficiently through reconnecting China's feed and dairy production sectors.