Leaf resorption and stoichiometry of N and P of 1, 2 and 3 year-old lucerne under one-time P fertilization
Leaf resorption and stoichiometry of N and P of 1, 2 and 3 year-old lucerne under one-time P fertilization
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一次性磷肥下1、2、3年生苜蓿叶片吸收及氮磷化学计量
DOI：
10.1016/j.still.2019.104481
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发表时间：
2020-03-01
影响因子：
6.5
通讯作者：
Li, Lingling
中科院分区：
文献类型：
--
作者：
Lu, Jiaoyun;Liu, Minguo;Li, Lingling
养分再吸收是植物保存养分和减少对土壤养分有效性依赖的关键过程之一，使植物更能适应不利环境。磷肥对豆科植物叶片养分再吸收的影响目前还不清楚。在土壤磷素有效性受到严重限制的黄土高原地区，研究了土壤磷素再吸收和化学计量学对磷肥施用的即时效应和事后效应的响应。研究了1-3年生卢塞恩（Medicago sativa L.）的氮素吸收效率（NRE）、磷素吸收效率（PRE）、绿色叶N：P（N：P-gr）和衰老叶N：P（N：P-sen），这是这个雨养地区广泛使用的饲料。在1 ~ 3年生范围内，NRE和PRE随林龄的增加而增加。施磷对NRE无影响，但对PRE有显著影响。第一年的PRE随施磷量的增加而增加，第二年和第三年的PRE在60 kg P_2O_5/ha（-1）时最高。随着林龄的增加，N：P-gr逐渐降低，N：P-sen逐渐增加，表明沿着卢塞恩生长的P限制作用更强。一次施磷对氮素有效利用率无明显影响，但对氮素有效利用率有明显的年龄效应。与N：P-gr相比，N：P-sen可能更能代表土壤养分的相对限制。叶片养分再吸收量随叶片氮磷比的变化而变化，表明土壤养分相对限制发生了变化。在该地区，施60 kg P_2O_5/ha（-1）的磷肥可保证最大的PRE、相等的NRE和较高的干生物量生产。从磷资源的有限性和生产成本考虑，在黄土高原卢塞恩生产中，减少施磷量或减少施磷次数是较为理想的管理方式。
Nutrient resorption is one of the key processes of a plant to conserve nutrients and to less depend on soil nutrient availability, which makes the plant more adaptive to adverse environments. Understanding of the effect of phosphorus (P) fertilization on leaf nutrient resorption of legume species is still limited. The aim was to test the responses of leaf nutrient resorption and stoichiometry to immediate and post effects of P fertilization in the Loess Plateau of China where soil P availability is largely restricted due to soil erosion and drought. Nitrogen resorption efficiency (NRE), P resorption efficiency (PRE), green leaf N:P (N:P-gr) and senesced leaf N:P (N:P-sen) were investigated in 1-3 year lucerne (Medicago sativa L.), a widely used forage in this rainfed region. The NRE and PRE increased with stand age increase from 1 to 3 years. The P fertilization had no effect on NRE, but significantly affected PRE. The PRE increased with P fertilization in the first year and PRE was the highest at 60 kg P2O5 ha(-1) in the second and third years. The N:P-gr decreased and N:P-sen increased with stand age, suggesting more P limitation along lucerne growth. The one-time P fertilization imposed no impacts on NRE but on PRE in an age-specific way. Compared with N:P-gr, N:P-sen, may be more representative to show relative nutrient limitation in soils. Leaf nutrient resorption changed with leaf N:P which indicates the shift of relative nutrient limitation of soils. The P fertilization at 60 kg P2O5 ha(-1) could guarantee the greatest PRE, equal NRE and higher dry biomass production in this region. Considering P resource finiteness and production cost, reduced amount or frequency of P fertilization is a desirable way of management for lucerne production in the Loess Plateau of China.