Review Article Role of Litter Turnover in Soil Quality in...

Review ArticleRole of Litter Turnover in Soil Quality in Tropical DegradedLands of Colombia

Juan D Leoacuten and Nelson W Osorio

Universidad Nacional de Colombia Calle 59 A No 63-20 Oficina 14-330 050034 Medellın Colombia

Correspondence should be addressed to Juan D Leon jdleonunaleduco

Received 31 August 2013 Accepted 30 December 2013 Published 13 February 2014

Academic Editors X He C Le Bayon N Moritsuka and L E Parent

Copyright copy 2014 J D Leon and N W Osorio This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Land degradation is the result of soil mismanagement that reduces soil productivity and environmental services An alternativeto improve degraded soils through reactivation of biogeochemical nutrient cycles (via litter production and decomposition) is theestablishment of active restoration models using new forestry plantations agroforestry and silvopastoral systems On the otherhand passive models of restoration consist of promoting natural successional processes with native plants The objective in thisreview is to discuss the role of litter production and decomposition as a key strategy to reactivate biogeochemical nutrient cyclesand thus improve soil quality in degraded land of the tropics For this purpose the results of different projects of land restorationin Colombia are presented based on the dynamics of litter production nutrient content and decomposition The results indicatethat in only 6ndash13 years it is possible to detect soil properties improvements due to litter fall and decomposition Despite that lowsoil nutrient availability particularly of N and P seems to be major constraint to reclamation of these fragile ecosystems

1 Introduction

Soil degradation is the result of soilmismanagement reducingsoil productivity and environmental services [1 2] Themost common factors involved in land degradation are soilerosion deforestation overgrazing overtillage and surfacemining [2ndash4] According to the World Economic Forum60 of the earthrsquos ecosystem services have been degradedin the past 60 years In the tropics soil degradation affects500 million ha [5] threatening ecosystem services and foodsecurity for people in developing countries [6] Also the lackof proper practices (monocultures inadequate fertilizationlack of soil conservation practices and reduced tillage)contributes to degradation of soil [3 7ndash9] Soil degradationimplies a loss of soil organic matter structure porositywater infiltration and permeability and nutrient availabilityamong other considerations [10 11] In most of the cultivatedland of the tropics the horizon O (organic materials) hasdisappeared and the horizon A has been severely diminishedorganic amendments are rarely used and little is done toreuse crop residues This impact is particularly severe inthe land subjected to surface mining because of the loss of

all soil horizons (O A B and C) to expose under layermaterials (rocks or sediments) [11] In both scenarios thebiogeochemical cycles of nutrients have been broken leadingthus to more soil degradation and increasing the dependenceon inorganic fertilizers [12]

An alternative to improve soil quality of degraded landsis the establishment of new forestry plantations agroforestryand silvopastoral systems [13] which improve ecosystemservices such as litter supply nutrient cycling water infiltra-tion control of erosion and increasing of biodiversity [14ndash19] This occurs due to (i) the soil exploration by abundantroot system (ii) the protection of the soil surface againsterosion and (iii) the reactivation of nutrient cycling vialitter production and decomposition [20ndash23] Unfortunatelylittle is known about the impact of these alternatives ontropical soil parameters Our hypothesis is that in relativelyshort periods of time soil quality parameters (eg soil pHsoil organic matter content and plant nutrient availability)may be enhanced in degraded lands by the establishment offorestry plantations or agroforestry systems Our objectivewas to review the role of litter turnover from case studies indiverse ecological life zones of Colombia as a key strategy to

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 693981 11 pageshttpdxdoiorg1011552014693981

2 The Scientific World Journal

reactivate biogeochemical nutrient cycles and thus improvesoil quality in degraded lands of the tropics

2 Experimental Sites

We selected four separate experimental sites in Colombia(Piedras Blancas Santa Fe de Antioquia Caceres andCerete)in which land was severely degraded by diverse factors andexhibited contrasting climates and altitude ranging from dryor wet lowlands (18ndash560m of altitude) to moist highlands(sim2500m) (Table 1) In each site forest plantations or sil-vopastoral systems were established as a way of productiverehabilitation of these environments and were separatelystudied in diverse projects [5 7 13 24 25] Geographiclocation weather conditions land uses and soil types areprovided in Table 1 In the next sections we will discuss someprinciples of land rehabilitation litter production anddecom-position nutrient recycling and changes in soil parametersover timeThe results obtained from these experimental siteswill be used to illustrate the dynamics of land rehabilitationin the tropics

3 Litter Production and Decomposition

Fine litter production and decomposition are two importantprocesses that provide the main input to form soil organicmatter and regulate nutrient cycling in forest ecosystems[26] The rates at which both processes occur determine thethickness of the litter layer on the forest soil [17] Nutrientcycling in forestry systems is achieved when the fine litter isdecomposed by soil biota which determines forest primaryproductivity [27] Thus the role of litter in plant nutritionis determined by its turnover time [28] In fact in tropicalleached soils the standing litter satisfies most of nutritionalneed of trees as dense root systems are developed inside of it[29ndash31]

In degraded lands by mining activities the loss of litterand plant coverage on the soil surface disrupts biogeochem-ical cycles of nutrients [10] Land reclamation of these soilsmay be achieved by establishing forestry species which mustbe chosen based on their ability to adapt to extreme andrestrictive soil conditions [11]

4 Models of Land Restoration

Passive and active restoration models have been proposedto restore the functioning of ecological processes [9] indegraded lands Passive restoration models are based on nat-ural succession processes with minimal human interventionwhile active restoration models include planting trees at highdensity and their respective management [32]These restora-tion models may contribute to the amelioration of degradedsoils through fine litter production and decomposition assources of organic matter and nutrients [12]

Although passive restorationmodels are simple inexpen-sive and based on natural regeneration these processes arenot always successful [33 34] Alternatively active restorationmodels accelerate the restoration of ecosystem functioning

through the activation of soil biogeochemical cycling of plantnutrients and carbon sequestration [32] Several studies havedemonstrated that forestry plantations (activemodel) play animportant role in the improvement of soil quality [35ndash39]

In general an active model should be considered whenthe rate of degradation of the area of interest is high becausethe planted species can be established quickly and createbetter conditions for a more diverse biological communityWhen the state and rate of degradation are not severe themost appropriate model might be the passive restorationallowing a natural recovery of the ecosystem which hadadvantages from ecological and economic perspectives [9 4041]

An example of a successful active model in the humidtropics is the establishment of plantations ofAcacia genus (Aalbida A Senegal andAmangium) in land reclamation [42]A mangium grows quickly and has a high capacity to adaptto nutrient-poor acidic soils due to its capacity to establishsymbiotic associations with N

2fixing bacteria [43ndash45] and

mycorrhizal fungi [46 47] In extremely nutrient-poor soilAmangium has exhibited an outstanding growth rate higherthan other plant species such as Eucalyptus sp and Gmelinaarborea [11]

In tropical dry regions some other forest species havebeen planted for land reclamation This is the case ofAzadirachta indica A Juss (Neem) a plant species employedbroadly single or in mixed plantations its high-quality litterand rapid decomposition promote its use for improvingsoil quality in rocky and sandy lands that are prone todesertification [48] in soils degraded by surface mining [4950] and in soils affected by salinity [51]

5 Biogeochemical Nutrient CyclingConsiderations Applied to Land Restoration

Regardless of the restoration models used several aspectsrelated to nutrient cyclingmust be seriously considered Firstthe major source of soil organic matter in terrestrial ecosys-tems is the fine litter production The diverse plant tissuesthat compose fine litter (leaves small branches flowers fruitsand seeds) are accumulated on the soil surface and mustbe decomposed to release nutrients In many tropical soilsnutrients released from the litter are the most relevant sourceof plant nutrients [31] and humus formation [52 53] In thisway from a functional perspective the standing litter on thesoil surface is very important in the regulation of severalprocesses [54] that include soil protection against erosion[55] The rate of litter decay controls soil organic matterformation and nutrient input

The leaves constitute the most abundant and easilydecomposable fraction of the fine litterfall (sim70) [56]consequently the rate at which leaf litter is produced anddecomposed represents a significant aspect in restorationprograms of degraded soils For this reason plant specieswithabundant leaf litter production of rapid decomposition mustbe considered in such programs Therefore a low residencetime of leaf litter seems to be a key factor in the reactivationof biogeochemical nutrient cycles in degraded soils [57]

The Scientific World Journal 3

Table 1 General information on the experimental sites in Colombia

Ecological lifezonea

Geographiccoordinates Temperature (∘C) Precipitation

(mmyrminus1) Altitude (m) Land uses Source

Site Piedras Blancas Degradation type overgrazing-deforested Soil Typic Hapludandb

LMMF 06∘181015840N75∘301015840W

149 19482460 P patula plantation

[26 52]2440 C lusitanica plantation2480 Q humboldtii forest

Site Santa Fe de Antioquia Degradation type overgrazing-severely eroded Soil Typic Ustorthents

TDF 06∘541015840N75∘811015840W

266 1034 560 C leptostachyus succession forest [9 58]A indica plantation

Site Caceres Degradation type alluvial mining Soil Typic Paleudult

TWF 07∘451015840N75∘141015840W 280 2771 330 A mangium plantation [10 11]

Site Cerete Degradation type overgrazing-compacted soil Soil Fluvaquentic Endoaquepts

TDF 8∘511015840N75∘491015840W

280 1380 18A saman and G ulmifolia in

silvopastoral systems [24 25]Degraded grassland with D aristatum

and P maximumaHoldridge [59] (LMWF lower montane moist forest TDF tropical dry forest TWF tropical wet forest)bUSDA soil taxonomy [60]

The rate of leaf litter production is lower in tropicalhighland forests than in tropical lowland forests In the firstcase the values fluctuates 9-10 t haminus1 yrminus1 [61ndash64] while inlowlands the values are over 13 t haminus1 yrminus1 [65 66] This inputof organic matter and nutrients favors the activity of soilmicro- and mesobiota which controls not only ecosystemfunctioning and productivity via nutrient cycling but also theecosystem resilience against disturbance

Litter accumulation on soil surface results in a balancebetween litter production and decomposition In highlandtotal forest litter accumulation ranges between 10 and 17 t haminus1[28 52 67]The leaves usually were around 2ndash7 t haminus1 [52 6467 68]

6 Organic Matter Return Based on LitterProduction and Accumulation

In early works Jenny et al [69] proposed to measure therate of litter decomposition based on litter fall values andits accumulation Thus in tropical rain forest the litterfalland decomposition is continuous and practically constantIn short periods of time (119889119905) it is accepted that there is anequilibrium between production and decomposition (2)

119860119889119905 = 119896

119895(119865 + 119860) 119889119905 (1)

or

119860 = 119896

119895(119865 + 119860) (2)

where 119860 annual rate of litterfall (Mg haminus1 yrminus1) 119889119905 timedifference 119896

119895 constant that represents the litter fraction

that decays and 119865 litter amount accumulated before themeasuring of litterfall (Mg haminus1 yrminus1) Thus at equilibrium

the litter loss (decomposition) is compensated by the litteradditions (litter production)

119896

119895=

119860

(119865 + 119860)

(3)

The mean residence time (MRT119895) of the litter and the

nutrients in it can be estimated from the inverse of 119896119895

MRT119895=

1

119896

119895

=

(119865 + 119860)

119860

(4)

Consequently the leaf litter real return (LLRR) to soilcan be estimated as the product of annual leaf litter potentialreturn (119860) and 119896

119895

LLRR = 119860119896119895 (5)

It should be clear that in this estimation leaf litter (119860)represents the most important source for turnover of organicmatter in the ecosystem other organic materials in the litterfall such as flowers fruits and woody debris and aboveground litter accumulated previously (119865) are ignored On theother hand other processes such as herbivory volatilizationleaching runoff and microbial immobilization representlosses of organic matter that are not considered Thereforethis approach likely underestimatesoverestimates the totalturnover that occurs in the ecosystem

According to Nye [70] once the litter accumulates up toreach an equilibrium state the rate of litter addition in 119889119905willbe equal to the rate of litter loss in the same time period (6)From this equation the index 119896

119871is found (7)

119860119889119905 = 119896

119871119865119889119905 (6)

119896

119871=

119860

119865

(7)


Values of 119896119871gt 1 indicate a return of the litter layer below one

year [68] The mean residence time (MRT119871) of the litter and

the nutrients in it can be estimated from the inverse of 119896119871

MRT119871=

1

119896

119871

=

119865

119860

(8)

The litter accumulated in a forestry ecosystem usuallyhas lesser proportion of leaves than the litter that felt thissuggests a fragmentation of the original material to formunidentified material due to a rapid decomposition of labileorganic materials and nutrient release into the soil Leon etal [52] compared biogeochemical cycles of nutrients in anoak (Quercus humboldtii) forest and a Pinus patula plantationestablished in a degraded soil by overgrazing in the Andeanmountains of Antioquia ColombiaThe values of the decom-position constant for leaf litter 119896

119895 ranged between 058 (oak)

and 042 (pine) respectively (Table 2) These values werelower than those reported for tropical lowland forests (14ndash20 yrminus1) [71 72] and for tropical highland forests (20 yrminus1)[73] The MRT

119895of the leaf litter was 172 yr for the oak forest

and 236 yr for the pine plantationThe differences in the rateof decomposition may be explained in terms of the CN ratio(oak leaves = 39 pine leaves = 51) Torreta and Takeda [74]considered that critical values of CN ratio for litter rangedbetween 30 and 40 Aerts and Heil [75] reported that theCN ratio is a good predictor of the litter decompositionparticularly if the lignin content is low In addition the highercontent of polyphenols in the pine leaves may impair themicrobial activity and slows the decomposition rate [76 77]

The dynamics of woody debris are opposite to leaf litterin fact they accumulate over time In the oak plantationwoody debris represents 14 of the total litter fall while inthe litter accumulated they account for 29 because of theirlower decomposition rate A similar behavior was detectedin the pine plantation where woody debris represented 25of total litter fall and 30 of the accumulated litter Thusthe decomposition indexes obtained for woody materialsindicated their slow decomposition rate [56]

The fine leaf litter represents an important source oforganic matter and C to soil which favors the soil biolog-ical activity and the reestablishment of nutrient cycling indegraded soils However while litter decomposes the organicmatter and C inputs must be considered as potential returns

Restrepo et al [9] evaluated the potential use of bothactive and passive models to restore soil biogeochemicalnutrient cycles through fine litterfall and soil quality in trop-ical degraded dry lands by overgrazing (Tables 1 and 2) Theyfound that in degraded soils the passive restoration modelwith a six-year-old native species (Croton leptostachyus)showed a higher capacity to reestablish nutrient cyclingthan with an active restoration model using a six-year-oldplantation of neem (Azadirachta indica) In these degradedsoils the supply of litter by the established or successionalvegetation is a valuable source of organic matter and CIn the passive model the potential C return by leaf litterrepresented 114 kgC haminus1 yrminus1 the 119896

119895constant obtained in the

study was 06 the MRT was 17 yr and the real carbon returnwas 72 kg haminus1 yrminus1 Meanwhile the potential C return in the

active model (neem plantation) was 46 kg haminus1 yrminus1 and thereal C return of 33 kg haminus1 yrminus1

On the other hand Leon [78] reported that in plantationsof P patula established in degraded highland by overgrazingthe potential return of organic matter was 4866 kg haminus1 yrminus1given a 119896

119895of 04 the real return of organic matter was

1946 kg haminus1 yrminus1 (863 kgC haminus1 yrminus1)The 119896

119895values in Table 2 corresponding to restoration

projects are lower than those obtained from natural forestsand forestry plantations except those reported by SantaRegina and Tarazona [79] with leaf litter of forestry speciesin Northeastern Spain (119896

119895for P sylvestris = 031 and for Fagus

sylvatica = 029) Similarly Santa Regina [80] reported 119896119895of

052 for litter of Q rotundifolia and values of 026 for litter ofP pinea and P pinaster in Duero Spain

7 Organic Matter Return Based onthe Litter-Bag Approach

An alternative approach to determine the decomposition oforganic matter from litter materials is through the use of thelitter bag technique [22] and regression models [26] Thesemodels describe the weight loss of a leaf litter sample (eg10 g dry basis) disposed in litter-bags over time The mostcommon model used is the single exponential proposed byOlson [81]

119883

119905

119883

0

= 119890

minus119896119905 (9)

where 119883119905is the weight of the remaining material at moment

119905 1198830is the weight of the initial dry material 119890 is the base of

natural logarithm and 119896 is the decomposition rateThe amounts of time required for loss of 50 and 99 of

the initial material can be calculated as 11990550= minus0693119896 and

119905

99= minus4605119896 respectively [81 82]Decomposition rates obtained from restoration of dif-

ferent ecosystems in Colombia using this model are shownin Table 3 and Figure 1 These values correspond to valuesobserved in tropical forests and plantations (119896 = 01ndash48)as those reported by several authors [67 83 84] This meansthat the decomposition rates of litter in restoration projectsare quite similar to those of plantations and forest andpresumably contribute significantly in the supply of organicmatter and release of carbon and nutrients into degradedsoils [10 11]

In another project aiming to restore degraded lands byalluvial mining in Colombia an 11-year-old plantation ofA mangium had annual litter fall of 103Mg haminus1 [11 85]55 (57Mg haminus1) corresponding to the leaf fraction In thisplantation the 119896 from the Olson model fluctuated between125 and 180 Therefore the annual return of C from litterdecomposition was in the range of 20ndash24Mg of C haminus1 It islogical to consider that these values may be higher becauseof the restrictions imposed on the entrance of mesorganismsby the pore size of the litter-bag (sim2mm of diameter) Alsothe only fraction considered in this type of study was the leaflitter


00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

P patula

C lusitanica

Q humboldtii

Resid

ual d

ry m

atte

r (X

tX

0)

(a)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A mangium+

A mangiumminusResid

ual d

ry m

atte

r (X

tX

0)

(b)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A indica

C leptostachyus

Resid

ual d

ry m

atte

r (X

tX

0)

(c)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A saman

G ulmifolia

Resid

ual d

ry m

atte

r (X

tX

0)

(d)

Figure 1 Residual dry matter (119883119905119883

0) of leaf litter from restoration projects conducted in different regions of Colombia (a) Forest of

Q humboldtii and plantations of P patula and C lusitanica in humid highlands degraded by overgrazing (b) plantations of A mangiumestablished in degraded soils by alluvial mining (+ with soil tillage minus without soil tillage) (c) plantation of A indica and successional forestof C leptostachyus in degraded dry lowlands (d) silvopastoral systems with A saman and G ulmifolia in dry lowlands

Table 2 Indices calculated for leaf litter potential return (119860) leaf litter accumulation (119865) leaf litter real return (LLRR =119860119896119895) and real return

of C (RRC = LLRR times C content (()) (expressed inMg haminus1 yrminus1) in restoration projects conducted in Colombia MRT119895 mean residence time

(yr) and 119896119895 decomposition constant (yrminus1) 119865 values do not include the contribution of roots

Ecosystem 119860 119865 119896

119895MRT119895

LLRR RRC Source(Mg haminus1 yrminus1) (yrminus1) (yr) (Mg haminus1 yrminus1)

Forest of Q humboldtii 5313 3828 058 172 3088 1257 [52 78]P patula plantation 4866 6597 042 236 2066 0916 [52 78]Succession of C leptostachyus 0478 0239 067 150 0320 0079 [9]A indica plantation 0185 0073 072 139 0130 0034 [9 58]

In dry lands of Colombia the 119896 value obtained from theleaf litter of C leptostachyus (119896 = 34) was higher than thatfound in theA indica plantation (119896 = 16) [9 58] So the firsttype of leaf litter was decomposed faster than A indica leaflitter With leaf litterfall values of 478 kg haminus1 yrminus1 for the Cleptostachyus successional forest and 185 kg haminus1 yrminus1 for the119860 indica plantation the potential return of organic matterinto soil was 461 and 147 kg haminus1 yrminus1 respectively The valueof 119896 found in the A indica plantation corresponded to thosereported for the same plant species in restoration projects ofdegraded soil by mining in India [83] In this way the timeestimated to decompose 50 and 99 of the leaf litter wouldbe 11990505= 04 yr and 119905

099= 291 yr respectively

In silvopastoral systems established in dry lowlands ofColombia Martinez et al [24 25] found that the outstandingplant species were A saman and G ulmifolia with leaf

litterfall of 478 and 489 kg haminus1 yrminus1 respectively Based ontheir 119896 values (Table 3) and C contents (456 and 488resp) the potential returns of organic matter were 770(351 kgC haminus1 yrminus1) and 448 kg haminus1 yrminus1 (219 kgC haminus1 yrminus1)respectively

8 Nutrient Return to Degraded Soil

As mentioned above in tropical environments fine litterfallrepresents the main process that determines the potentialreturn of organic matter and nutrients to the soil whichsupports plant development and soil biota [86 87] Howevernutrient recycling is achieved when the litter is decomposedby soil biota a key process in forestry systems that determinessoil quality and forest primary productivity [27] If thenutrients are quickly released they could be lost by leaching


Table 3 Fitted models for residual dry matter (1198831199051198830) as a function of time for forest species from restoration projects in Colombia

Plant species 119896 119905

05(yr) 119905

099(yr) 119877

2 SourceQ humboldtii 102 068 451 933P patula 029 237 1577 885 [26]C lusitanica 037 190 1262 531C leptostachyus 336 021 137 9676 [9]A indica 158 044 291 8431 [9]A mangium 135ndash180 038ndash056 260ndash370 8682ndash9620 [11]A saman 096 072 478 923

[24 25]G ulmifolia 247 028 186 89011990505 decomposition time for half of the leaf litter 119905099 decomposition time for 99of the leaf litter 119896 yearly decomposition rate1198772 coefficient of determination()

or volatilization [88 89] If the decomposition occurs slowlythe nutrient supply to plant roots will be insufficient thuslimiting plant growth anddevelopment [90 91] For these rea-sons the rates at which litter decomposition and subsequentnutrient release occur constitute key factors for ecosystemfunctioning In the case of reclamation of degraded landsthis may be achieved by establishing forestry species of rapidgrowth which must be selected according to their abilityto adapt to extreme and restrictive soil and weather condi-tionsThrough litter decomposition and consequent nutrientrelease the vegetation can contribute to the improvement ofsoil quality due to their capacity to induce ecological andphysicochemical changes in the soil [38 39]

The potential nutrient return via leaf litter production inforest ecosystems has been widely reported in many studiesOn the other hand this kind of reports in restoration projectsof tropical degraded lands is scarce High values of N returnvia leaf litter (52ndash81 kgNhaminus1 yrminus1) were reported by Leon etal [11] inAmangium established in degraded soils by alluvialgold mining (Table 4) Likely this high return is due to theability of this plant to form symbiotic association with N

2

fixing bacteria which allow having high N concentration inthe leaf litter (12) [85]This is a remarkable aspect desirablefor a forest species selected for a soil reclamation project asthis symbiosis offers independence of the plant from the soilN reservoir

On the other hand the values found for the potentialreturn of P are consistently very low in most restorationprojects (006ndash170 kg haminus1 yrminus1 Table 4) This low level ofP in the leaf litter exerts a severe restriction for microbialactivity and plant growth in these soils As a consequencelow leaf litter concentrations of P can be found (0001ndash004) representing a major limiting factor in nutrientcycling and plant nutrition in tropical environments Thelow P concentration in the litter may be a limiting factorfor decomposers given their high P requirements [92] Infact the NP ratio of 124 obtained in A mangium litter isconsiderably higher than the critical value of 12 reported forthe leaf litterfall [93] For this reason it has been proposedthat inoculation with mycorrhizal fungi and phosphate solu-bilizing microorganisms in restoration projects of degradedland in the tropics is highly recommended [47 94]

Similarly in the restoration projects of degraded drylands ecosystems with C leptostachyus forests and A indica

plantations there was an extremely low availability of P inthe soil which was reflected in the low values of P returnthrough leaf litter (Table 4) and in the high levels of NP ratio(A indica leaf litter 43 C leptostachyus leaf litter 20) [9] Bythe same way in coniferous forest plantations established inhighlands of Colombia very low values for potential P returnwere found (08ndash17 kg haminus1 yrminus1) [14] Likely it was also theresult of extremely low soil P availability in the volcanic-ashsoils where the study was carried out [26] Mean values of theNP ratio of the leaf litter of this study were 198 and 195 forpine and cypress litters respectively Again these values ofN P ratio suggest a P deficiency in both materials consequentlysoil reclamation could be constrained by this P deficiency

In general nutrient return via leaf litter follows thedecreasing sequence N gt Ca gt Mg gt K gt P neverthelessin some cases the potential return of Ca can be higher thanthat of N (Table 4) In fact the mean concentrations of Caand Mg in the leaf litter of C leptostachyus (18 and 06resp) and A indica (22 and 05) are very high and differfrom those found in other tropical dry lowland forests [95]This is the result of the high availability of both nutrients inthat soil which favored their uptake by both plant species Incontrast the litter K concentrations found in the Neem leaflitter (ca 029) by Florez-Florez et al [58] are close to thelower end of the pantropic interval (027 plusmn 011) suggested byDuivenvoorden and Lips [96] This potential K scarcity maybe due to the high levels of soil exchangeableMg which couldaffect the primary productivity in those plantations andconsequently limiting leaf litter K concentrations [9] Theseaspects should be carefully monitored in land reclamationprojects as they can impair the success of restoration projects

9 Soil Quality Improvement in RestorationProjects

The organic matter and nutrient supply exerted by the litterproduction and decomposition have the potential to enhancesoil properties [22] In different projects abovementionedaiming reclamation of degraded lands we have detectedincrease in some soil properties such as soil organic matter(SOM) soil aggregate stability (SAS) soil total N (SN

119905) soil

available P (SAP) and cation exchangeable capacity (CEC)(Table 5) Restrepo et al [9] also reported a significantly


Table 4 Potential return of nutrients via leaf litterfall from the dominant plant species in different ecosystems obtained from restorationprojects conducted in Colombia

Ecosystemecological life zone Nutrient return SourceN P Ca Mg K

(kg haminus1 yrminus1)P patula plantation 444 17 188 45 36 [52]C lusitanica plantation 132 08 261 14 17 [52]Succession of C leptostachyus 52 022 84 28 13 [9 58]A indica plantation 24 006 46 09 05 [9 58]A mangium plantation 52ndash81 03ndash08 24ndash35 6ndash9 7ndash13 [10 11]A saman in silvopastoral system 348 10 122 15 43 [24 25]G ulmifolia in silvopastoral system 112 07 161 21 38 [24 25]

Table 5 Changes in some soil properties of degraded soils in Colombia by the establishment of forestry species

Site conditions andreclamation strategy Soil pH SOM () SAS () SNt () SAP (mg kgminus1) CEC (cmolc kg

minus1) Source

Degraded land by alluvial miningUnplanted control 54 61 730 024 25 61 [10 11]11-year-old plantation of Amangium 45lowast 187lowast 854lowast 050lowast 65lowast 112lowast

Degraded land by overgrazingUnplanted control 63 20 730 021 33 130

[9 58]6-year-old plantation of Aindica 64 34lowast 801 027lowast 43lowast 148

6-year-old forest of Cleptostachyus 63 42lowast 685 025 18 259lowast

Degraded land by overgrazingDegraded grassland 55 89 ND ND 96 217

[24 25]13-year-old A saman insilvopastoral system 58lowast 84 ND ND 140lowast 223

13-year-old G ulmifolia insilvopastoral system 62lowast 90 ND ND 241lowast 245lowast

Analytical methods are available inWesterman [97] soil pH (water 1 1) SOM (Walkley and Black) soil organic matter CEC (1M ammonium acetate) cationexchange capacity SAS (Yoder method) soil aggregate stability SAP (Bray II) soil available P lowastSignificant difference with control sites (Mann-Whitney 119875 le005) ND not determined

decrease in the soil bulk density from 135Mgmminus3 in thecontrol sites to 125Mgmminus3 in the planted sites with either Aindica or C leptostachyus (both 6-year-old) This representsan increase in soil porosity and water retention which is amajor change in this dry environment In addition Martinezet al [24 25] indicated that soil exchangeable K increasedfrom078 cmolc kg

minus1 in the degraded grassland up to 095 and119 cmolc kg

minus1 in the soil influenced by the litterfall of thetrees A saman and G ulmifolia (both 13-year-old) A similarsituationwas detected for Ca (107 cmolc kg

minus1 in the grasslandsoil and 124 and 138 cmolc kg

minus1 in the soil withA saman andG ulmifolia litterfall resp)

These changes detected in soil properties represent ulti-mately the benefits associated with the reactivation of bio-geochemical cycle via litterfall production and decomposi-tion which in turn will likely improve plant performanceSurprisingly these changes were detected in relative shortperiods of time (6ndash13 years) after the establishment of therespective plantations or successional forest Noteworthy is

the significant increase in SOM reported by Leon et al [10]and Restrepo et al [9] since the SOM is key factor in soil andecosystem functioning for plant nutrition soil sustainabilityand protection as reported by Fernandes et al [98] in Braziland Mafongoya et al [99] in Africa Likely these changes areassociated with an improvement in soil microbial activity anddiversity [100]

The increases in soil available P and cation exchangecapacity as a result of litter influence are outstanding becausethese two properties severely impair soil quality and plantperformance in the tropics The low soil P availability seemsto be one of themost critical issues for land reclamation in thetropics in order to manage this problem the coinoculationwith mycorrhizal fungi and phosphate solubilizing P mayhelp to reduce this limitation [101] On the other hand soilN limitation may be offset with the combined employ oforganic amendments and themassive employ of legume treescapable of forming symbiotic association with effective N

2

fixing bacteria


10 Future Research Guidelines

Currently the strong alterations on ecosystem functionsproduced by soil mismanagement after the conversion ofnatural ecosystems into agricultural systems or mining activ-ities are broadly accepted These alterations have affectedessential ecological processes and life support systems bybreaking out biogeochemical cycles and other biosphereprocesses (eg nutrient cycling water supply and waterregulation) Environmental and land use planning agenciesin tropical countries as Colombia where high deforesta-tion and land degradation rates have occurred need todevelop proper knowledge of both structural and func-tional ecosystem parameters for measuring degrees of landdegradation Furthermore these parameters would allowdetermining the effectiveness of reclamation activities ondegraded lands which can control the degradation processesNutrient cycling as a major ecosystem function providesmeaningful services that have both direct and indirect bene-fits to future reclamation activities through active and passivestrategies Regardless the strategy employed litter turnoverand nutrient release should be carefully studied to revealthe effectiveness of the measures taken In fact it has beenfound that restoration strategies carried out in degraded landshave enhanced soil quality parameters such as increasingorganic matter content and nutrient availability regulatingsoil pH improving soil aggregate stability and providinghigher water holding capacity However little has been doneon the impact of these strategies on soil microorganisms suchasmycorrhizal fungiN

2fixersmineral solubilizers andplant

growth promoters which can enhance plant performanceand soil remediation

It has to be pointed out that these studies will demandeconomical resources not always available to make theextended monitoring of processes abovementioned viableThe lack of these financial resources should be overcome bystate agencies through their science and technology systemsas well as some private institutions by means of fiscalmechanisms to encourage their participation in developingresearch and applied programs in degraded land reclamation

11 Conclusions

The organic matter and nutrient return rate via litterfalldepends on many factors that influence decompositionprocess at the ecosystem level Plant species selected forreclamation of degraded soils should preferably be able toestablish symbiotic associations with soil microorganisms(ie mycorrhizal fungi and N

2fixing bacteria) Furthermore

these species must show a high capacity to adapt to nutrient-poor acidic soils Because microbial activity is severelyrestricted in degraded soils the selected species must havehigh nutrient use efficiencyThe reclamation of degraded soilrequires deep knowledge of the litter dynamics (eg litterfall nutrient content and decomposition rate) because thisdetermines the rate of organic matter and C supply to thesoil and the nutrient cycling reactivation In relatively shortperiods of time it is possible to detect the improvement ofsome soil properties due to litter fall and decomposition

Despite that low soil availability of N and P seems to bethe major constraints in reclamation of degraded soil in thetropics for which the use of legume trees and inoculationwith beneficial microorganisms (eg N

2fixing bacteria

mycorrhizal fungi andmineral solubilizingmicroorganisms)should be an integral part of the management of these fragileecosystems

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] J F Reynolds and D M Stafford-Smith Global DesertificationDo Humans Cause Deserts Dahlem University Press BerlinGermany 2002

[2] S B StClair and J P Lynch ldquoThe opening of Pandorarsquos Boxclimate change impacts on soil fertility and crop nutrition indeveloping countriesrdquo Plant and Soil vol 335 no 1 pp 101ndash1152010

[3] R Lal ldquoLaws of sustainable soil managementrdquo in Sustain-able Agriculture E Lichtfouse M Navarrete P Debaeke SVeronique and C Alberola Eds pp 9ndash12 Springer Amster-dam The Netherlands 2009

[4] R Lal ldquoSoil degradation as a reason for inadequate humannutritionrdquo Food Security vol 1 pp 45ndash57 2009

[5] D Lamb P D Erskine and J A Parrotta ldquoRestoration ofdegraded tropical forest landscapesrdquo Science vol 310 no 5754pp 1628ndash1632 2005

[6] M Herrero P K Thornton A M Notenbaert et al ldquoSmartinvestments in sustainable food production revisiting mixedcrop-livestock systemsrdquo Science vol 327 no 5967 pp 822ndash8252010

[7] S Mejıa S Reza P Argel et al ldquoAlternativas de manejo depasturas de Colosuana o kikuyina (Bothriochloa pertusa) ensistemas ganaderos del tropico bajo Informe Finalrdquo Corpo-racion Colombiana de Investigacion Agropecuaria Ministeriode Agricultura y Desarrollo Rural Colombia 2008

[8] Y S Cajas-Giron and F L Sinclair ldquoCharacterization of mul-tistrata silvopastoral systems on seasonally dry pastures in theCaribbean Region of Colombiardquo Agroforestry Systems vol 53no 2 pp 215ndash225 2001

[9] M F Restrepo C P Florez J D Leon and N W OsorioldquoPassive and active restoration strategies to activate soil biogeo-chemical nutrient cycles in a degraded tropical dry landrdquo ISRNSoil Science vol 2013 Article ID 461984 6 pages 2013

[10] J D Leon N W Osorio J Castellanos and L F OsorioldquoRecuperacion de suelos degradados por minerıa aluvial deoro con plantaciones de acacia en la region del Bajo Cauca(Antioquia Colombia)rdquo Suelos Ecuatoriales vol 40 pp 62ndash672010

[11] J D Leon J Castellanos M Casamitjana N W Osorio andJ C Loaiza ldquoAlluvial gold-mining degraded soils reclamationusing Acacia mangium plantations an evaluation from bio-geochemistryrdquo in Plantations Biodiversity Carbon Sequestrationand Restoration R Hai Ed pp 155ndash176 Nova Science NewYork Ny USA 2013

[12] N W Osorio Soil Nutrient Management in the Tropics Univer-sidad Nacional de Colombia Medellin Colombia 2012


[13] R V Kohli H P Singh D R Batish and S Jose ldquoEcologicalinteractions in agroforestry an overviewrdquo in Ecological Basis ofAgroforestry D R Batish R V Kohli S Jose and H P SinghEds pp 3ndash14 CRC Press Boca Raton Fla USA 2008

[14] EMurgueitio Z Calle FUribeACalle andB Solorio ldquoNativetrees and shrubs for the productive rehabilitation of tropicalcattle ranching landsrdquo Forest Ecology andManagement vol 261no 10 pp 1654ndash1663 2011

[15] J Sierra and P Nygren ldquoTransfer of N fixed by a legume treeto the associated grass in a tropical silvopastoral systemrdquo SoilBiology and Biochemistry vol 38 no 7 pp 1893ndash1903 2006

[16] M E Wedderburn and J Carter ldquoLitter decomposition byfour functional tree types for use in silvopastoral systemsrdquo SoilBiology and Biochemistry vol 31 no 3 pp 455ndash461 1999

[17] JHMcadamA R Sibbald Z Teklehaimanot andWR EasonldquoDeveloping silvopastoral systems and their effects on diversityof faunardquo Agroforestry Systems vol 70 no 1 pp 81ndash89 2007

[18] U Ilstedt A Malmer E Verbeeten and D Murdiyarso ldquoTheeffect of afforestation on water infiltration in the tropicsa systematic review and meta-analysisrdquo Forest Ecology andManagement vol 251 no 1-2 pp 45ndash51 2007

[19] M Lemenih M Olsson and E Karltun ldquoComparison ofsoil attributes under Cupressus lusitanica and Eucalyptussaligna established on abandoned farmlands with continuouslycropped farmlands and natural forest in Ethiopiardquo Forest Ecol-ogy and Management vol 195 no 1-2 pp 57ndash67 2004

[20] B M Kumar ldquoLitter dynamics in plantation and agroforestrysystems of the tropics-a review of observations and methodsrdquoin Ecological Basis of Agroforestry D R Batish R V Kohli SJose and H P Singh Eds pp 181ndash216 CRC Press Boca RatonFla USA 2008

[21] S Zingore R Chikowo G Nyamadzawo P Nyamugafata andP L Mafongoya ldquoDevelopments in the research of the potentialof agroforestry for sustaining soil fertility in Zimbabwerdquo inEcological Basis of Agroforestry D R Batish R V Kohli S Joseand H P Singh Eds pp 217ndash237 CRC Press Boca Raton FlaUSA 2008

[22] F Montagnini ldquoSoil sustainability in agroforestry systemsexperiences on impacts of trees on soil fertility from a humidtropical siterdquo in Ecological Basis of Agroforestry D R Batish RV Kohli S Jose and H P Singh Eds pp 239ndash251 CRC PressBoca Raton Fla USA 2008

[23] S Jose S C Allen and P K R Nair ldquoTree-crop interactionslessons from temperate alley-cropping systemsrdquo in EcologicalBasis of Agroforestry D R Batish R V Kohli S Jose and H PSingh Eds pp 15ndash36 CRC Press Boca Raton Fla USA 2008

[24] J Martinez Produccion y descomposicion de hojarasca ensistemas silvo-pastoriles de estratos multiples y su efecto sobrepropiedades bio-organicas del suelo en el valle medio del Rıo Sinu[PhD thesis] Universidad Nacional de Colombia Cundina-marca Colombia 2013

[25] JMartinez S Cajas J D Leon andNWOsorio ldquoSilvopastoralsystems enhance soil quality in grasslands of Colombiardquo Journalof Applied and Environmental Soil Science In press

[26] J C Loaiza-Usuga J D Leon-Pelaez J A Ramırez-Correaet al ldquoAlterations in litter decomposition patterns in tropicalmontane forests of Colombia a comparison of oak forests andconiferousrdquoCanadian Journal of Forest Research vol 3 pp 528ndash533 2013

[27] Q Wang S Wang and Y Huang ldquoComparisons of litterfalllitter decomposition and nutrient return in amonocultureCun-ninghamia lanceolata and a mixed stand in southern Chinardquo

Forest Ecology andManagement vol 255 no 3-4 pp 1210ndash12182008

[28] J Weerakkody and D Parkinson ldquoInput accumulation andturnover of organic matter nitrogen and phosphorus in surfaceorganic layers of an upper montane rainforest in Sri LankardquoPedobiologia vol 50 no 4 pp 377ndash383 2006

[29] E V J Tanner P M Vltousek and E Cuevas ldquoExperimentalinvestigation of nutrient limitation of forest growth on wettropical mountainsrdquo Ecology vol 79 no 1 pp 10ndash22 1998

[30] F Garcıa-Oliva B Sveshtarova and M Oliva ldquoSeasonal effectson soil organic carbon dynamics in a tropical deciduous forestecosystem in western Mexicordquo Journal of Tropical Ecology vol19 no 2 pp 179ndash188 2003

[31] A Parzych and J Trojanowski ldquoPrecipitation and duff fall asnatural sources of nitrogen and phosphorus forforest soils in theSłowinski National Parkrdquo Baltic Coastal Zone vol 10 pp 47ndash592006

[32] D Celentano R A Zahawi B Finegan R Ostertag R J Coleand K D Holl ldquoLitterfall dynamics under different tropicalforest restoration strategies in Costa Ricardquo Biotropica vol 43no 3 pp 279ndash287 2011

[33] K D Holl ldquoTropical moist forest restorationrdquo in Handbook ofEcological Restoration M R Perrow and A J Davy Eds pp539ndash558 Cambridge University Press Cambridge UK 2002

[34] J Schrautzer A Rinker K Jensen F Muller P Schwartzeand C Dier Ben ldquoSuccession and restoration of drained fensperspectives from northwestern Europerdquo in Linking Restorationand Ecological Succession L R Walker J Walker and R JHobbs Eds pp 90ndash120 Springer New York NY USA 2007

[35] A E Lugo E Cuevas and M J Sanchez ldquoNutrients and massin litter and top soil of ten tropical tree plantationsrdquo Plant andSoil vol 125 no 2 pp 263ndash280 1990

[36] J A Parrotta ldquoProductivity nutrient cycling and successionin single- and mixed-species plantations of Casuarina equiseti-folia Eucalyptus robusta and Leucaena leucocephala in PuertoRicordquo Forest Ecology andManagement vol 124 no 1 pp 45ndash771999

[37] A E Lugo ldquoThe apparent paradox of reestablishing speciesrichness on degraded lands with tree monoculturesrdquo ForestEcology and Management vol 99 no 1-2 pp 9ndash19 1997

[38] C T Garten Jr ldquoSoil carbon storage beneath recently estab-lished tree plantations in Tennessee and South Carolina USArdquoBiomass and Bioenergy vol 23 no 2 pp 93ndash102 2002

[39] G Singh B Singh V Kuppusamy and N Vala ldquoVariations infoliage and soil nutrient composition in Acacia tortilis plan-tations of different ages in North-Western Rajashtanrdquo IndianForester vol 128 pp 514ndash521 2002

[40] D Lamb andDGilmour Issues in Forest Conservation Rehabili-tation and Restoration of Degraded Forests International Unionfor Conservation of Nature and Natural Resources and WorldWide Fund Cambridge UK 2003

[41] J-P Laclau J-P Bouillet and J Ranger ldquoDynamics of biomassand nutrient accumulation in a clonal plantation of Eucalyptusin Congordquo Forest Ecology and Management vol 128 no 3 pp181ndash196 2000

[42] J Ribet and J-J Drevon ldquoThe phosphorus requirement of N2-

fixing and urea-fed Acacia mangiumrdquo New Phytologist vol 132no 3 pp 383ndash390 1996

[43] A R Higa and R C V Higa ldquoIndicacoes de especies parao reflorestamentordquo in Reflorestamento de Propriedades Ruraispara Fins Produtivos e Ambientais Um Guia para Acoes Munic-ipais e Regionai A P M Galvao Ed pp 101ndash124 Embrapa


Comunicacao para Transferencia de Tecnologia e EmbrapaFlorestas Brasilia Brazil 2000

[44] I Garay R Pellens A Kindel E Barros and A A FrancoldquoEvaluation of soil conditions in fast-growing plantations ofEucalyptus grandis and Acacia mangium in Brazil a contribu-tion to the study of sustainable land userdquo Applied Soil Ecologyvol 27 no 2 pp 177ndash187 2004

[45] M T Lim ldquoStudies on Acacia mangium in Kemasul ForestMalaysia I Biomass and productivityrdquo Journal of TropicalEcology vol 4 no 3 pp 293ndash302 1988

[46] R Duponnois and A M Ba ldquoGrowth stimulation of AcaciamangiumWilld byPisolithus sp in some Senegalese soilsrdquoForestEcology and Management vol 119 no 1ndash3 pp 209ndash215 1999

[47] N W Osorio and J D Leon ldquoRoles of arbuscular mycorrizalassociation in plant nutrition and growth of tropical forestryand agroforestry in degraded soil reclamationrdquo in PlantationsBiodiversity Carbon Sequestration and Restoration R Hai Edpp 127ndash154 Nova Science New York NY USA 2013

[48] S A Radwanski and G E Wickens ldquoVegetative fallows andpotential value of the neem tree (Azadirachta indica) in thetropicsrdquo Economic Botany vol 35 no 4 pp 398ndash414 1981

[49] V S Mehrotra ldquoArbuscular mycorrhizal associations of plantscolonizing coal mine spoil in IndiardquoThe Journal of AgriculturalScience vol 130 no 2 pp 125ndash133 1998

[50] A Singh A K Jha and J S Singh ldquoEffect of nutrient enrich-ment on native tropical trees planted on Singrauli CoalfieldsIndiardquo Restoration Ecology vol 8 no 1 pp 80ndash86 2000

[51] V Singh and V K Garg ldquoPhytoremediation of a sodic forestecosystem plant community response to restoration processrdquoNotulae Botanicae Horti Agrobotanici Cluj-Napoca vol 35 pp77ndash85 2007

[52] J D Leon M I Gonzalez and J F Gallardo ldquoCiclos bio-geoquımicos en bosques naturales y plantaciones de conıferasen ecosistemas de alta montana de Colombiardquo Revista deBiologıa Tropical vol 59 pp 1883ndash1894 2011

[53] J F Gallardo A Martın and I Santa Regina ldquoNutrient cyclingin deciduous forest ecosystems of the Sierra de Gatamountainsaboveground litter production and potential nutrient returnrdquoAnnals of Forest Science vol 55 no 7 pp 749ndash769 1998

[54] W Wilcke S Yasin U Abramowski C Valarezo and WZech ldquoNutrient storage and turnover in organic layers undertropical montane rain forest in Ecuadorrdquo European Journal ofSoil Science vol 53 no 1 pp 15ndash27 2002

[55] S Roig M del Rıo I Canellas and G Montero ldquoLitter fallin Mediterranean Pinus pinaster Ait stands under differentthinning regimesrdquo Forest Ecology andManagement vol 206 no1ndash3 pp 179ndash190 2005

[56] V Meentemeyer ldquoMacroclimate the lignin control of litterdecomposition ratesrdquo Ecology vol 59 pp 465ndash472 1978

[57] D L Moorhead and R L Sinsabaugh ldquoA theoretical model oflitter decay and microbial interactionrdquo Ecological Monographsvol 76 no 2 pp 151ndash174 2006

[58] C P Florez-Florez J D Leon-Pelaez N W Osorio-Vega andM F Restrepo-Llano ldquoDinamica de nutrientes en plantacionesforestales establecidas para restauracion de tierras degradadasen Colombiardquo Revista Biologıa Tropical vol 61 pp 515ndash5292013

[59] L R Holdridge Life Zone Ecology Tropical Science Center SanJose Costa Rica 1967

[60] S Buol F D Hole R J McCraken and R J Southard SoilGenesis and Classification Iowa State University Press AmesIowa USA 1997

[61] B Lundgren ldquoSoil conditions and nutrient cycling undernatural and plantation forests in Tanzanian highlandsrdquo Reportsin Forest Ecology and Forest Soils 31 Swedish University ofAgricultural Sciences Uppsala Sweden 1978

[62] I Kunkel-Westphal and P Kunkel ldquoLitter fall in a Guatemalanprimary forest with details of leaf-shedding by some commontree speciesrdquo Journal of Ecology vol 67 pp 665ndash686 1979

[63] Z X Zou Xiaoming C P Zucca R B Waide and WH McDowell ldquoLong-term influence of deforestation on treespecies composition and litter dynamics of a tropical rain forestin Puerto Ricordquo Forest Ecology andManagement vol 78 no 1ndash3pp 147ndash157 1995

[64] M A McDonald and J R Healey ldquoNutrient cycling in sec-ondary forests in the BlueMountains of Jamaicardquo Forest Ecologyand Management vol 139 no 1ndash3 pp 257ndash278 2000

[65] N C Songwe F E Fasehun and D U U Okali ldquoLitterfall andproductivity in a tropical rain forest Southern Bakundu ForestReserve Cameroonrdquo Journal of Tropical Ecology vol 4 no 1pp 25ndash37 1988

[66] J I del Valle ldquoCantidad calidad y nutrientes reciclados porla hojarasca fina en bosques pantanosos del Pacıfico SurColombianordquo Interciencia vol 28 pp 443ndash449 2003

[67] S M Sundarapandian and P S Swamy ldquoLitter production andleaf-litter decomposition of selected tree species in tropicalforests at Kodayar in the Western Ghats Indiardquo Forest Ecologyand Management vol 123 no 2-3 pp 231ndash244 1999

[68] D A Scott J Proctor and J Thompson ldquoEcological studieson a lowland evergreen rain forest on Maraca Island RoraimaBrazil II Litter and nutrient cyclingrdquo Journal of Ecology vol 80no 4 pp 705ndash717 1992

[69] H Jenny S P Gessel and F T Bingham ldquoComparative studyof decomposition of organic matter in temperate and tropicalregionsrdquo Soil Science vol 68 pp 419ndash432 1949

[70] P H Nye ldquoOrganic matter and nutrient cycles under moisttropical forestrdquo Plant and Soil vol 13 no 4 pp 333ndash346 1960

[71] J M Anderson J Proctor and H W Vallack ldquoEcologicalstudies in four contrasting lowland rain forests in GunungMulu National Park Sarawak III Decomposition processes andnutrient losses from leaf litterrdquo Journal of Ecology vol 71 no 2pp 503ndash527 1983

[72] K Smith H L Gholz and F D A Oliveira ldquoLitterfall andnitrogen-use efficiency of plantations and primary forest in theeastern Brazilian Amazonrdquo Forest Ecology and Managementvol 109 no 1ndash3 pp 209ndash220 1998

[73] T B A Burghouts N M van Straalen and L A BruijnzeelldquoSpatial heterogeneity of element and litter turnover in aBornean rain forestrdquo Journal of Tropical Ecology vol 14 no 4pp 477ndash506 1998

[74] N K Torreta and H Takeda ldquoCarbon and nitrogen dynamicsof decomposing leaf litter in a tropical hill evergreen forestrdquoEuropean Journal of Soil Biology vol 35 no 2 pp 57ndash63 1999

[75] R Aerts and G W Heil Heathlands Patterns and Processesin a Changing Environment Kluwer Academic Dordrecht TheNetherlands 1993

[76] J K Egunjobi and B S Onweluzo ldquoLitter fall mineral turnoverand litter acumulation in Pinus caribaea L stands at IbadanNigeriardquo Biotropica vol 11 pp 251ndash255 1979

[77] J Castellanos-Barliza and J D Leon ldquoDescomposicion dehojarasca y liberacion de nutrientes en plantaciones de Aca-cia mangium (Fabales Mimosaceae) establecidas en suelosdegradados de Colombiardquo Revista Biologıa Tropical vol 59 pp113ndash128 2011


[78] J D Leon Contribucion al Conocimiento del Ciclo de Nutri-entes en Bosques Montanos Naturales de Quercus humboldtiiy Reforestados (Pinus patula y Cupressus lusitanica) de laRegion de Piedras Blancas Antioquia (Colombia) [PhD thesis]Universidad de Salamanca Salamanca Spain 2007

[79] I Santa Regina and T Tarazona ldquoNutrient cycling in a naturalbeech forest and adjacent planted pine in northern SpainrdquoForestry vol 74 no 1 pp 11ndash28 2001

[80] I Santa Regina ldquoLitter fall decomposition and nutrient releasein three semi-arid forests of the Duero basin Spainrdquo Forestryvol 74 no 4 pp 347ndash358 2001

[81] J Olson ldquoEnergy storage and balance of producers and decom-poser in ecological systemsrdquo Ecology vol 44 pp 322ndash331 1963

[82] A Arunachalam and N D Singh ldquoLeaf litter decomposition ofevergreen and deciduous Dillenia species in humid tropics ofnorth-east Indiardquo Journal of Tropical Forest Science vol 14 no1 pp 105ndash115 2002

[83] K P Singh P K Singh and S K Tripathi ldquoLitterfall litterdecomposition and nutrient release patterns in four native treespecies raised on coalmine spoil at Singrauli IndiardquoBiology andFertility of Soils vol 29 no 4 pp 371ndash378 1999

[84] D Kurzatkowski C Martius H Hofer et al ldquoLitter decom-position microbial biomass and activity of soil organisms inthree agroforestry sites in central Amazoniardquo Nutrient Cyclingin Agroecosystems vol 69 no 3 pp 257ndash267 2004

[85] J Castellanos and J D Leon ldquoCaıda de hojarasca y dinamica denutrientes en plantaciones de Acacia mangium (Mimosaceae)deAntioquia ColombiardquoActaBiologicaColombiana vol 15 pp289ndash308 2010

[86] L Norgrove and S Hauser ldquoProduction and nutrient contentof earthworm casts in a tropical agrisilvicultural systemrdquo SoilBiology and Biochemistry vol 32 no 11-12 pp 1651ndash1660 2000

[87] R K Dutta and M Agrawal ldquoLitterfall litter decompositionand nutrient release in five exotic plant species planted on coalmine spoilsrdquo Pedobiologia vol 45 no 4 pp 298ndash312 2001

[88] R M Palma J Prause A V Fontanive and M P JimenezldquoLitter fall and litter decomposition in a forest of the ParqueChaquenoArgentinordquo Forest Ecology andManagement vol 106no 2-3 pp 205ndash210 1998

[89] W H Schlesinger Biogeoquımica Un Analisis Global ArielCiencia Barcelona Spain 2000

[90] K A Bubb Z H Xu J A Simpson and P G Saffigna ldquoSomenutrient dynamics associated with litterfall and litter decom-position in hoop pine plantations of southeast QueenslandAustraliardquo Forest Ecology and Management vol 110 no 1ndash3 pp343ndash352 1998

[91] F Montagnini and C F Jordan ldquoReciclaje de nutrientesrdquoin Ecologıa y Conservacion de Bosques Neotropicales M RGuariguata and G Kattan Eds pp 167ndash191 LUR CartagoCosta Rica 2002

[92] M J Swift O W Heal and J M Anderson Decomposition inTerrestrial Ecosystems vol 5 of Studies in Ecology University ofCalifornia Press Berkeley Calif USA 1979

[93] R Aerts ldquoClimate leaf litter chemistry and leaf litter decompo-sition in terrestrial ecosystems a triangular relationshiprdquoOikosvol 79 no 3 pp 439ndash449 1997

[94] N W Osorio and M Habte ldquoSynergistic effect of a phosphate-solubilizing fungus and an arbuscular mycorrhizal fungus onleucaena seedlings in an Oxisol fertilized with rock phosphaterdquoBotany vol 91 pp 274ndash281 2013

[95] A N Singh A S Raghubanshi and J S Singh ldquoComparativeperformance and restoration potential of two Albizia speciesplanted onmine spoil in a dry tropical region Indiardquo EcologicalEngineering vol 22 no 2 pp 123ndash140 2004

[96] J M Duivenvoorden and J F Lips A Land-Ecologycal Studyof Soils Vegetation and Plant Diversity in Colombian Amazo-nia vol 12 of Tropenbos Series The Tropenbos FoundationWageningen The Netherlands 1995

[97] R L Westerman Soil Testing and Plant Analysis Soil ScienceSociety of America Madison Wis USA 1990

[98] EM Fernandes EWandelli R Perin and SGarcia ldquoRestoringproductivity to degraded pasture lands in the Amazon throughAgroforestry Practicesrdquo in Biological Approaches to SustaInableSoil Systems N Uphoff Ed pp 305ndash322 CRC Press BocaRaton Fla USA 2006

[99] P L Mafongoya E Kuntashula and G Sileshi ldquoManaging soilfertility and nutrient cycles through fertilizer trees in SouthernAfricardquo in Biological Approaches to Sustainable Soil Systems NUphoff Ed pp 273ndash289 CRC Press Boca Raton Fla USA2006

[100] J EThies and JMGrossman ldquoThe soil habitat and soil ecologyrdquoin Biological Approaches to Sustainable Soil Systems N UphoffEd pp 59ndash78 CRC Press Boca Raton Fla USA 2006

[101] G Schroth and U Krauss ldquoBiological soil fertility managementfor tree-crop agroforestryrdquo in Biological Approaches to Sustain-able Soil Systems N Uphoff Ed pp 291ndash303 CRC Press BocaRaton Fla USA 2006

Submit your manuscripts athttpwwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Environmental and Public Health

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Applied ampEnvironmentalSoil Science

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Geological ResearchJournal of

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Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


ClimatologyJournal of


reactivate biogeochemical nutrient cycles and thus improvesoil quality in degraded lands of the tropics

2 Experimental Sites

We selected four separate experimental sites in Colombia(Piedras Blancas Santa Fe de Antioquia Caceres andCerete)in which land was severely degraded by diverse factors andexhibited contrasting climates and altitude ranging from dryor wet lowlands (18ndash560m of altitude) to moist highlands(sim2500m) (Table 1) In each site forest plantations or sil-vopastoral systems were established as a way of productiverehabilitation of these environments and were separatelystudied in diverse projects [5 7 13 24 25] Geographiclocation weather conditions land uses and soil types areprovided in Table 1 In the next sections we will discuss someprinciples of land rehabilitation litter production anddecom-position nutrient recycling and changes in soil parametersover timeThe results obtained from these experimental siteswill be used to illustrate the dynamics of land rehabilitationin the tropics

3 Litter Production and Decomposition

Fine litter production and decomposition are two importantprocesses that provide the main input to form soil organicmatter and regulate nutrient cycling in forest ecosystems[26] The rates at which both processes occur determine thethickness of the litter layer on the forest soil [17] Nutrientcycling in forestry systems is achieved when the fine litter isdecomposed by soil biota which determines forest primaryproductivity [27] Thus the role of litter in plant nutritionis determined by its turnover time [28] In fact in tropicalleached soils the standing litter satisfies most of nutritionalneed of trees as dense root systems are developed inside of it[29ndash31]

In degraded lands by mining activities the loss of litterand plant coverage on the soil surface disrupts biogeochem-ical cycles of nutrients [10] Land reclamation of these soilsmay be achieved by establishing forestry species which mustbe chosen based on their ability to adapt to extreme andrestrictive soil conditions [11]

4 Models of Land Restoration

Passive and active restoration models have been proposedto restore the functioning of ecological processes [9] indegraded lands Passive restoration models are based on nat-ural succession processes with minimal human interventionwhile active restoration models include planting trees at highdensity and their respective management [32]These restora-tion models may contribute to the amelioration of degradedsoils through fine litter production and decomposition assources of organic matter and nutrients [12]

Although passive restorationmodels are simple inexpen-sive and based on natural regeneration these processes arenot always successful [33 34] Alternatively active restorationmodels accelerate the restoration of ecosystem functioning

through the activation of soil biogeochemical cycling of plantnutrients and carbon sequestration [32] Several studies havedemonstrated that forestry plantations (activemodel) play animportant role in the improvement of soil quality [35ndash39]

In general an active model should be considered whenthe rate of degradation of the area of interest is high becausethe planted species can be established quickly and createbetter conditions for a more diverse biological communityWhen the state and rate of degradation are not severe themost appropriate model might be the passive restorationallowing a natural recovery of the ecosystem which hadadvantages from ecological and economic perspectives [9 4041]

An example of a successful active model in the humidtropics is the establishment of plantations ofAcacia genus (Aalbida A Senegal andAmangium) in land reclamation [42]A mangium grows quickly and has a high capacity to adaptto nutrient-poor acidic soils due to its capacity to establishsymbiotic associations with N

2fixing bacteria [43ndash45] and

mycorrhizal fungi [46 47] In extremely nutrient-poor soilAmangium has exhibited an outstanding growth rate higherthan other plant species such as Eucalyptus sp and Gmelinaarborea [11]

In tropical dry regions some other forest species havebeen planted for land reclamation This is the case ofAzadirachta indica A Juss (Neem) a plant species employedbroadly single or in mixed plantations its high-quality litterand rapid decomposition promote its use for improvingsoil quality in rocky and sandy lands that are prone todesertification [48] in soils degraded by surface mining [4950] and in soils affected by salinity [51]

5 Biogeochemical Nutrient CyclingConsiderations Applied to Land Restoration

Regardless of the restoration models used several aspectsrelated to nutrient cyclingmust be seriously considered Firstthe major source of soil organic matter in terrestrial ecosys-tems is the fine litter production The diverse plant tissuesthat compose fine litter (leaves small branches flowers fruitsand seeds) are accumulated on the soil surface and mustbe decomposed to release nutrients In many tropical soilsnutrients released from the litter are the most relevant sourceof plant nutrients [31] and humus formation [52 53] In thisway from a functional perspective the standing litter on thesoil surface is very important in the regulation of severalprocesses [54] that include soil protection against erosion[55] The rate of litter decay controls soil organic matterformation and nutrient input

The leaves constitute the most abundant and easilydecomposable fraction of the fine litterfall (sim70) [56]consequently the rate at which leaf litter is produced anddecomposed represents a significant aspect in restorationprograms of degraded soils For this reason plant specieswithabundant leaf litter production of rapid decomposition mustbe considered in such programs Therefore a low residencetime of leaf litter seems to be a key factor in the reactivationof biogeochemical nutrient cycles in degraded soils [57]







LMMF 06∘181015840N75∘301015840W




TDF 06∘541015840N75∘811015840W





TDF 8∘511015840N75∘491015840W








119860119889119905 = 119896

119895(119865 + 119860) 119889119905 (1)

or

119860 = 119896

119895(119865 + 119860) (2)





119896

119895=

119860

(119865 + 119860)

(3)



MRT119895=

1

119896

119895

=

(119865 + 119860)

119860

(4)


119895

LLRR = 119860119896119895 (5)



119871is found (7)

119860119889119905 = 119896

119871119865119889119905 (6)

119896

119871=

119860

119865

(7)





MRT119871=

1

119896

119871

=

119865

119860

(8)






















119883

119905

119883

0

= 119890

minus119896119905 (9)





119905





00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

P patula

C lusitanica

Q humboldtii

Resid

ual d

ry m

atte

r (X

tX

0)

(a)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A mangium+

A mangiumminusResid

ual d

ry m

atte

r (X

tX

0)

(b)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A indica

C leptostachyus

Resid

ual d

ry m

atte

r (X

tX

0)

(c)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A saman

G ulmifolia

Resid

ual d

ry m

atte

r (X

tX

0)

(d)







Ecosystem 119860 119865 119896

119895MRT119895












05(yr) 119905

099(yr) 119877





2








119905) soil








minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics




















LMMF 06∘181015840N75∘301015840W




TDF 06∘541015840N75∘811015840W





TDF 8∘511015840N75∘491015840W








119860119889119905 = 119896

119895(119865 + 119860) 119889119905 (1)

or

119860 = 119896

119895(119865 + 119860) (2)





119896

119895=

119860

(119865 + 119860)

(3)



MRT119895=

1

119896

119895

=

(119865 + 119860)

119860

(4)


119895

LLRR = 119860119896119895 (5)



119871is found (7)

119860119889119905 = 119896

119871119865119889119905 (6)

119896

119871=

119860

119865

(7)





MRT119871=

1

119896

119871

=

119865

119860

(8)






















119883

119905

119883

0

= 119890

minus119896119905 (9)





119905





00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

P patula

C lusitanica

Q humboldtii

Resid

ual d

ry m

atte

r (X

tX

0)

(a)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A mangium+

A mangiumminusResid

ual d

ry m

atte

r (X

tX

0)

(b)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A indica

C leptostachyus

Resid

ual d

ry m

atte

r (X

tX

0)

(c)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A saman

G ulmifolia

Resid

ual d

ry m

atte

r (X

tX

0)

(d)







Ecosystem 119860 119865 119896

119895MRT119895












05(yr) 119905

099(yr) 119877





2








119905) soil








minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics


















MRT119871=

1

119896

119871

=

119865

119860

(8)






















119883

119905

119883

0

= 119890

minus119896119905 (9)





119905





00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

P patula

C lusitanica

Q humboldtii

Resid

ual d

ry m

atte

r (X

tX

0)

(a)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A mangium+

A mangiumminusResid

ual d

ry m

atte

r (X

tX

0)

(b)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A indica

C leptostachyus

Resid

ual d

ry m

atte

r (X

tX

0)

(c)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A saman

G ulmifolia

Resid

ual d

ry m

atte

r (X

tX

0)

(d)







Ecosystem 119860 119865 119896

119895MRT119895












05(yr) 119905

099(yr) 119877





2








119905) soil








minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics















00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

P patula

C lusitanica

Q humboldtii

Resid

ual d

ry m

atte

r (X

tX

0)

(a)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A mangium+

A mangiumminusResid

ual d

ry m

atte

r (X

tX

0)

(b)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A indica

C leptostachyus

Resid

ual d

ry m

atte

r (X

tX

0)

(c)

00

02

04

06

08

10

0 60 120 180 240 300 360Time (days)

A saman

G ulmifolia

Resid

ual d

ry m

atte

r (X

tX

0)

(d)







Ecosystem 119860 119865 119896

119895MRT119895












05(yr) 119905

099(yr) 119877





2








119905) soil








minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics

















05(yr) 119905

099(yr) 119877





2








119905) soil








minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics




















minus1) Source

















2

fixing bacteria







11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics




















11 Conclusions





2fixing bacteria




References
















































































































Journal of












Volume 2014

Advances in









Geophysics

















































































































Journal of












Volume 2014

Advances in









Geophysics














Review Article Role of Litter Turnover in Soil Quality in...

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