Effects of nitrogen fertilization on soil nutrient concentration and phosphatase activity and forage nutrient uptake from a grazed pasture system
Effects of nitrogen fertilization on soil nutrient concentration and phosphatase activity and forage nutrient uptake from a grazed pasture system
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DOI：
10.1016/j.jenvman.2015.02.035
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发表时间：
2015-05-01
影响因子：
8.7
通讯作者：
Muntifering, Russell Brian
中科院分区：
文献类型：
--
作者：
Dillard, Sandra Leanne;Wood, Charles Wesley;Muntifering, Russell Brian
在3年的时间里，研究了不同施氮制度对富磷放牧系统土壤可提取磷浓度、土壤磷酸酶活性和牧草磷吸收的影响。每年秋季，将6块0.28公顷的小黑麦（x Triticosecale rimpaui Wittm.）和深红色三叶草（Trifolium incarnatum）过度播种到高羊茅(Lolium arundinacea)/百米草（Cynodon dactylon）草皮中，并分配3种氮肥处理中的1种（n = 2）：分施100%推荐施氮（100N），单施50% (50N)，小黑麦施0%推荐施氮（ON）。第二年春天，牛群开始吃草，一直吃到五月。在夏季，在地块上过量播种豇豆（Vigna unguiculata），参照百慕大草的氮肥建议以相同的比率施肥，并由牛放牧到9月。施氮对土壤磷酸酶活性、电导率和水溶性磷含量均无影响，施氮量为50N的样地可提取磷含量下降，但施氮量增加至100N后可提取磷含量没有进一步下降，但在植物群落水平上，施氮量对牧草生物量、叶面磷浓度和牧草磷质量没有影响，但在单个牧草种内观察到响应。结果表明，按草组分农艺推荐量的50%施氮可增加特定牧草的饲用磷质量，减少土壤可提取磷，从而为减少放牧牧草的磷损失提供了机会。(C) 2015 Elsevier Ltd.版权所有。
Over a 3-year period, the effect of differing N-application regimes on soil extractable-P concentration, soil phosphatase activity, and forage P uptake in a P-enriched grazed-pasture system was investigated. In the fall of each year, six 0.28-ha plots were overseeded with triticale (x Triticosecale rimpaui Wittm.) and crimson clover (Trifolium incarnatum) into a tall fescue (Lolium arundinacea)/bermudagrass (Cynodon dactylon) sod and assigned to 1 of 3 N-fertilizer treatments (n = 2): 100% of N recommendation in a split application (100N), 50% in a single application (50N), and 0% of N recommendation (ON) for triticale. Cattle commenced grazing the following spring and grazed until May. In the summer, plots were overseeded with cowpea (Vigna unguiculata), fertilized at the same rates by reference to N recommendations for bermudagrass, and grazed by cattle until September. There were no effects of N fertilization on soil phosphatase activity, electrical conductivity, or concentrations of water-soluble P. Concentrations of extractable P decreased in plots receiving 50N, but increasing N fertilization to 100N resulted in no further reduction in extractable P. Forage biomass, foliar P concentrations, and forage P mass were not affected by N fertilization rates at the plant-community level, but responses were observed within individual forage species. Results are interpreted to mean that N fertilization at 50% of the agronomic recommendation for the grass component can increase forage P mass of specific forages and decrease soil extractable P, thus providing opportunity for decreasing P losses from grazed pasture. (C) 2015 Elsevier Ltd. All rights reserved.