Koerselman W,Meuleman A F M.The vegetation N∶P ratio:a new tool to detect the nature of nutrient limitation[J].Journal of Applied Ecology,1996:1441-1450.
[2]
Verhoeven J,Koerselman W,Meuleman A.Nitrogen-or phosphorus-limited growth in herbaceous,wet vegetation:relations with atmospheric inputs and management regimes[J].Trends in Ecology & Evolution,1996,11(12):494-497.
[3]
Aerts R,Chapin F S.The mineral nutrition of wild plants revisited:a re-evaluation of processes and patterns[M]/Fitter A H R D.Advances in Ecological Research,Vol 30.London,UK:Academic Press Inc,2000:30,1-67.
[4]
Marschner H.Mineral Nutrition of Higher Plants[M].London:Academic Press,1995:889.
[5]
Guha M M,Mitchell R L.The trace and major element composition of the leaves of some deciduous trees[J].Plant and Soil,1965,23(3):323.
[6]
Aerts R.Nutrient resorption from senescing leaves of perennials:Are there general patterns?[J].Journal of Ecology,1996,84(4):597-608.
[7]
Eckstein R L,Karlsson P S,Weih M.Leaf life span and nutrient resorption as determinants of plant nutrient conservation in temperate-arctic regions[J].New Phytologist,1999,143(1):177-189.
[8]
Killingbeck K T,Whitford W G.Nutrient resorption in shrubs growing by design,and by default in Chihuahuan Desert arroyos[J].Oecologia,2001,128(3):351-359.
[9]
Distel R A,Moretto A S,Didone N G.Nutrient resorption from senescing leaves in two Stipa species native to central Argentina[J].Austral Ecology,2003,28(2):210-215.
[10]
Killingbeck K T.Nutrients in senesced leaves:keys to the search for potential resorption and resorption proficiency[J].Ecology,1996,77(6):1716-1727.
[11]
Skujins J.Nitrogen Cycling in Arid Ecosystems[R].Stockholm,1981:477-491.
[12]
Su Y Z,Li Y L,Cui H Y,et al.Influences of continuous grazing and livestock exclusion on soil properties in a degraded sandy grassland,Inner Mongolia,northern China[J].Catena,2005,59(3):267-278.
[13]
Drenovsky R E,Richards J H.Critical N∶P values:predicting nutrient deficiencies in desert shrublands[J].Plant and Soil,2004,259(1/2):59-69.
[14]
Chapin F S.The mineral-nutrition of wild plants[J].Annual Review of Ecology and Systematics,1980,11:233-260.
[15]
Quested H M,Cornelissen J H C,Press M C,et al.Decomposition of sub-arctic plants with differing nitrogen economies:a functional role for hemiparasites[J].Ecology,2003,84(12):3209-3221.
[16]
Taylor B R,Parsons W F J,Parkinson D.Decomposition of populus-tremuloides leaf litter accelerated by addition of alnus-crispa litter[J].Canadian Journal of Forest Research,1989,19(5):674-679.
[17]
Berg B,Johansson M B,Meentemeyer V.Litter decomposition in a transect of Norway spruce forests:substrate quality and climate control[J].Canadian Journal of Forest Research,2000,30(7):1136-1147.
[18]
Moretto A S,Distel R A.Decomposition of and nutrient dynamics in leaf litter and roots of Poa ligularis and Stipa gyneriodes[J].Journal of Arid Environments,2003,55(3):503-514.
[19]
Berendse F.Effects of dominant plant species on soils during succession in nutrient-poor ecosystems[J].Biogeochemistry,1998,42(1/2):73-88.
[20]
Aerts R,Verhoeven J T A,Whigham D F.Plant-mediated controls on nutrient cycling in temperate fens and bogs[J].Ecology,1999,80(7):2170-2181.
[21]
Sankaran M,Ratnam J,Hanan N P.Tree-grass coexistence in savannas revisited-insights from an examination of assumptions and mechanisms invoked in existing models[J].Ecology Letters,2004,7(6):480-490.
[22]
Leffler A J,Peek M S,Ryel R J,et al.Hydraulic redistribution through the root systems of senesced plants[J].Ecology,2005,86(3):633-642.
[23]
Zou C B,Barnes P W,Archer S,et al.Soil moisture redistribution as a mechanism of facilitation in Savanna tree-shrub clusters[J].Oecologia,2005,145(1):32-40.
[24]
Mcculley R L,Jobbagy E G,Pockman W T,et al.Nutrient uptake as a contributing explanation for deep rooting in arid and semi-arid ecosystems[J].Oecologia.2004,141(4):620-628.
[25]
Bertiller M B,Sain C L,Carrera A L,et al.Patterns of nitrogen and phosphorus conservation in dominant perennial grasses and shrubs across an aridity gradient in Patagonia,Argentina[J].Journal of Arid Environments,2005,62(2):209-223.
[26]
Chapin F S,Kedrowski R A.Seasonal-changes in nitrogen and phosphorus fractions and autumn retranslocation in evergreen and deciduous taiga trees[J].Ecology,1983,64(2):376-391.
[27]
Birk E M,Vitousek P M.Nitrogen availability and nitrogen use efficiency in loblolly-pine stands[J].Ecology,1986,67(1):69-79.
[28]
Escudero A,Delarco J M,Garrido M V.The efficiency of nitrogen retranslocation from leaf biomass in quercus-ilex ecosystems[J].Vegetatio,1992,99/100:225-237.
[29]
Vitousek P M,Howarth R W.Nitrogen limitation on land and in the sea: how can it occur?[J].Biogeochemistry,1991,13(2):87-115.
[30]
Yuan Z Y,Li L H,Han X G,et al.Nitrogen resorption from senescing leaves in 28 plant species in a semi-arid region of northern China[J].Journal of Arid Environments,2005,63(1):191-202.
[31]
Ratnam J,Sankaran M,Hanan N P,et al.Nutrient resorption patterns of plant functional groups in a tropical savanna:variation and functional significance[J].Oecologia,2008,157(1):141-151.
[32]
Eckstein R L,Karlsson P S,Weih M.The significance of resorption of leaf resources for shoot growth in evergreen and deciduous woody plants from a subarctic environment[J].Oikos,1998,81(3):567-575.
[33]
Norby R J,Cotrufo M F,Ineson P,et al.Elevated CO2,litter chemistry,and decomposition:a synthesis[J].Oecologia,2001,127(2):153-165.
[34]
Knops J M H,Bradley K L,Wedin D A.Mechanisms of plant species impacts on ecosystem nitrogen cycling[J].Ecology Letters,2002,5(3):454-466.
[35]
Luo Y,Zhao X,Zuo X,et al.Leaf nitrogen resorption pattern along habitats of semi-arid sandy land with different nitrogen status[J].Polish Journal of Ecology,2010,58(4):707-716.
Li F R,Zhao L Y,Zhang H,et al.Wind erosion and airborne dust deposition in farmland during spring in the Horqin Sandy Land of eastern Inner Mongolia,China[J].Soil & Tillage Research,2004,75(2):121-130.
[43]
Zhang T H,Zhao H L,Li S G,et al.Grassland changes under grazing stress in Horqin sandy grassland in Inner Mongolia,China[J].New Zealand Journal of Agricultural Research,2004,47(3):307-312.