The role of nitrogen fixation and nutrient supply in some agroforestry systems of the Americas

Kass, Donald; Sylvester-Bradley, Rosemary; Nygren, Pekka

doi:10.1016/s0038-0717(96)00269-6

Cited by 45 publications

(23 citation statements)

References 34 publications

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“…The low nutrient stocks in the soil were probably due to the constant removal at harvest (ASP) and by grazing (in SP). Kass et al (1997) emphasized that in agroforestry systems, the high rates of nutrient removal retard the accumulation of N and soil organic matter. Thus, several years of AFSs would be needed to accumulate more pronounced levels.…”

Section: Figura 4 -Estoque De C N P K Ca E Mg Na Biomassa Das Plamentioning

confidence: 99%

“…The productivity level in the ASP was above the regional averages found for traditional crops (IPECE, 2011b). In the agroforestry systems, the conditions of imbalance imposed by cultivation practices and the constant nutrient withdrawal by crops are offset favorably by the management practices adopted in this area, such as incorporation of adventitious plants in the soil (KASS et al, 1997). These imbalance conditions mean that there is, for example, higher content of nutrients added to the soil via herbaceous plants mowed regularly and left on the ground.…”

Section: Figura 4 -Estoque De C N P K Ca E Mg Na Biomassa Das Plamentioning

confidence: 99%

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Carbon sequestration and nutrient reserves under differen t land use systems

et al. 2014

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-This study evaluated the contribution of agroforestry (AFS) and traditional systems to carbon sequestration and nutrient reserves in plants, litter and soil. The study was carried out in the semiarid region of Brazil in a long-term experiment on an experimental farm of the goat and sheep section of the Brazilian Agricultural Research Corporation (Embrapa). Two agroforestry systems were investigated: agrosilvopastoral (ASP) and forest-pasture areas (SP) as well as traditional agriculture management (TM), two areas left fallow after TM (six fallow years -F6 and nine fallow years -F9) and one area of preserved Caatinga vegetation (CAT). Soil, litter and plants were sampled from all areas and the contents of C, N, P, K, Ca and Mg per compartment determined. The AFS (ASP and SP) had higher nutrient stocks than the traditional and intermediate stocks compared to the preserved Caatinga. In the ASP, a relevant part of the nutrients extracted by crops is returned to the system by constant inputs of litter, weeding of herbaceous vegetation and cutting of the legume crops. After fallow periods of six and nine years, carbon and nutrient stocks in the compartments soil, litter and herbaceous plants were similar to those of the preserved Caatinga (CAT), but still lower than under natural conditions in the woody vegetation.Keywords: Agroecology; Family farming; Agroforestry. SEQUESTRO DE CARBONO E RESERVA DE NUTRIENTES EM DIFERENTES SISTEMAS DE USO DA TERRA

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Section: Figura 4 -Estoque De C N P K Ca E Mg Na Biomassa Das Plamentioning

confidence: 99%

Section: Figura 4 -Estoque De C N P K Ca E Mg Na Biomassa Das Plamentioning

confidence: 99%

Carbon sequestration and nutrient reserves under differen t land use systems

et al. 2014

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“…Recycling of legume litter is usually considered as the main pathway (e.g. Kass et al 1997;Beer et al 1998;Mafongoya et al 1998). Yet it has been observed that decomposition of litter, roots and nodules explains only about a third of the observed below-ground N transfer (Sierra et al 2002;Dulormne et al 2003; see also Dubach and Russelle 1994).…”

Section: Introductionmentioning

confidence: 99%

Root exudates of a legume tree as a nitrogen source for a tropical fodder grass

Jalonen

Nygren

Sierra³

2009

Nutr Cycl Agroecosyst

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Exudation of nitrogenous compounds from the roots of dinitrogen-fixing plants is a potential source of nitrogen for adjacent plants in intercropping systems. We studied (1) the extent of N exudation from the roots of a tropical legume tree Gliricidia sepium (Jacq.) Kunth ex Walp., and (2) the ability of a C4 fodder grass Dichantium aristatum (Poir) C.E. Hubbard and its mycorrhizal symbionts to absorb N from tree exudates in a glasshouse experiment. Root exudates of 15 N-labelled trees were collected in hydroponic culture and applied with irrigation water on grass grown in separate pots. During the 10-week experiment, the trees exuded 34.1 ± 5.0 mg of N, which represented 1.7 ± 0.2% of their total N by the end of the experiment. The total amount exuded would have been enough to supply 16% of grass N content by the end of the experiment. The grass, however, absorbed only 3.8-7.5% of 15 N in exudates and gained 0.8-1.1% of its N from exudates. The low absorption of exudate N by grass was explained by probable soil microbial immobilisation and by the dilution of exuded N in the substantially larger pool of soil mineral N. A close contact between the root systems of N donor and recipient plants directly or via their mycorrhizal symbionts seems to be a precondition of the apparently direct N transfer earlier observed in field studies of the same soil-plant system.

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“…The use of legume trees is motivated by the assumed benefit of symbiotic fixation of atmospheric dinitrogen by the trees for the whole AFS. Both traditional knowledge and research results indicate that the presence of legume trees has beneficial effects on soil fertility in many tropical AFS (Kass et al 1997). These benefits include increased soil and microbial C and N content in comparison to annual cropping (Mazzarino et al 1993;Sierra et al 2002), increased residual soil N content after legume-enriched fallows in comparison to continuous cropping (Ståhl et al 2002), and long-term accumulation of C and N in soil in simultaneous AFS (Dulormne et al 2003;Haggar et al 1993;Sierra and Nygren 2005).…”

Section: Introductionmentioning

confidence: 99%

Natural abundance of 15N in two cacao plantations with legume and non-legume shade trees

Nygren¹,

Leblanc

2008

Agroforest Syst

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Natural abundance of 15 N was sampled in young and mature leaves, branches, stem, and coarse roots of trees in a cacao (Theobroma cacao) plantation shaded by legume tree Inga edulis and scattered nonlegumes, in a cacao plantation with mixed-species shade (legume Gliricidia sepium and several non-legumes), and in a tree hedgerow bordering the plantations in Guácimo, in the humid Caribbean lowlands of Costa Rica. The deviation of the sample 15 N proportion from that of atmosphere (d 15 N) was similar in non-legumes Cordia alliodora, Posoqueria latifolia, Rollinia pittieri, and T. cacao. Deep-rooted Hieronyma alchorneoides had lower d 15 N than other non-N 2 -fixers, which probably reflected uptake from a partially different soil N pool. Gliricidia sepium had low d 15 N. Inga edulis had high d 15 N in leaves and branches but low in stem and coarse roots. The percentage of N fixed from atmosphere out of total tree N (%N f ) in G. sepium varied 56-74%; N 2 fixation was more active in July (the rainiest season) than in March (the relatively dry season). The variation of d 15 N between organs in I. edulis was probably associated to 15 N fractionation in leaves. Stem and coarse root d 15 N was assumed to reflect the actual ratio of N 2 fixation to soil N uptake; stem-based estimates of %N f in I. edulis were 48-63%. Theobroma cacao below I. edulis had lower d 15 N than T. cacao below mixed-species shade, which may indicate direct N transfer from I. edulis to T. cacao but results so far were inconclusive. Further research should address the 15 N fractionation in the studied species for improving the accuracy of the N transfer estimates. The d 15 N appeared to vary according to ecophysiological characteristics of the trees.

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The role of nitrogen fixation and nutrient supply in some agroforestry systems of the Americas

Cited by 45 publications

References 34 publications

Carbon sequestration and nutrient reserves under differen t land use systems

Carbon sequestration and nutrient reserves under differen t land use systems

Root exudates of a legume tree as a nitrogen source for a tropical fodder grass

Natural abundance of 15N in two cacao plantations with legume and non-legume shade trees

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