Barros, D. M.

de Mello, Alexandre C. L.

Dubeux, José C. B., Jr.

Lira, M. A.

Santos, M. V. F.

Silva, M. A.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Characterization of Soil Properties under Legume and Non‐Legume Tree Canopies Occurring in Signal Grass (Brachiaria decumbensStapf.) Pastures José C. B. Dubeux Jr. Universidade Federal Rural de Pernambuco, Brazil M. A. Lira Instituto Agronômico de Pernambuco, Brazil M. V. F. Santos Universidade Federal Rural de Pernambuco, Brazil D. M. Barros Universidade Federal Rural de Pernambuco, Brazil M. A. Silva Universidade Federal Rural de Pernambuco, Brazil See next page for additional authors Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/10-1/14 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. Presenter Information José C. B. Dubeux Jr., M. A. Lira, M. V. F. Santos, D. M. Barros, M. A. Silva, and Alexandre C. L. de Mello This event is available at UKnowledge: https://uknowledge.uky.edu/igc/21/10-1/14 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]201　 瞯Grasslands/Rangelands Production Systems——— Integration of Crops , Forage and Forest SystemsCharacterization of soil properties under legume and non‐legume tree canopies occurring in signalgrass (Brachiaria decumbens Stapf .) pasturesJ .C .B . Dubeux , Jr .1 ; M .A . L ira2 ; M .V .F . Santos 1 ; D .M . Barros1 ; M .A . Silv a1 ; A .C .L . Mello11 UFRPE‐Departamento de Zootecnia , R . Dom Manoel de Medeiros , S / N , Dois I rmaos , Recife , PE , Braz il , 52171‐900 ; e‐mail : dubeux＠ dz .uf rpe .br ; 2 IPA‐A v .General San Martin , Bongi , Reci f e , PE , Braz il .Key words : agroforestry ,nutrient cycling ,shade ,soil fertility ,soil organic matterIntroduction Trees improve the soil by numerous processes , mainly when used in agroforestry systems , where different speciesare cultivated in the same area . Legume trees influence nutrient availability within the root zone of the intercropped species bydifferent processes such as : i) N biologic fixation ; ii) nutrient recovery from deeper soil layers ; iii) reduction in soil erosion andrunoff ; and iv) increasing nutrient bioavailability by increasing soil organic matter ( SOM ) mineralization . The objective of thisresearch was to evaluate the total soil organic matter and soil Mehlich‐I P at different points underneath the tree crown ,according to a shade gradient of legume and non‐legume trees occurring on signalgrass ( Brachiaria decumbens Stapf .)pastures .Material and methods The experiment was carried out in the coastal region of Pernambuco State , in Itambe AgriculturalResearch Station from IPA . Geographical coordinates are ７°２５′０″S lat . and ３５°６′０″W longitude with １９０ m above sea level .Average annual rainfall in this area is １ ,３００ mm and the soil is classified as an oxisol . Soil samples were taken according to thecrown projection of two legume trees ( Mimosa caesalp inii f olia Benth . and Machaerium aculeatum raddi .) and two non‐legume trees ( A nacardium occidentale L .and A rtocarpus integri f olia L .) . Samples were taken at １０％ , ５０％ , １００％ , and１５０％ of shade projection at the ０‐１０ cm soil layer . Soil analyses of these samples were accomplished at UFRPE , determiningtotal SOM and soil Mehlich‐I P ( EMBRAPA , １９９９) . Data was analyzed as complete randomized design ( proc mixed SAS) andnon‐linear and linear models were used ( proc nonlin SAS) to fit the data whenever the shade gradient was significant .Results Soil fertility was greater under the crown projection as shown by SOM ( Table １ ) and Mehlich‐I P ( Table ２ ) for allevaluated tree species . Total SOM showed a negative exponential pattern ( P ＜ ０ .０１) , w ith greater SOM concentration closer tothe tree trunk . Legume trees showed less SOM accumulation than non‐legume trees . This might be related to tree age andcrown projection . Non‐legume trees had a wider and denser crown than the legume ones . Shade may affect soil temperature andsoil microbe activity , modifying decomposition rates . In addition to that , residue deposition likely differs among evaluatedspecies , affecting SOM accumulation . Available P (Mehlich‐I) showed a linear decrease , with sun‐exposed areas showing lesssoil P . Considering that these trees occur in a pasture area , cattle manure deposition may contribute to increase soil P under thecrown projection (Dubeux et al , ２００７ ) .Table 1 Total SOM ( g /kg ) according to a shade gradientunder legume and non‐legume trees occurring on signalgrassp astures , I també‐PE , Braz il .Crow n projection ( ％ )Species １０ �５０ "１００ Z１５０  g OM / kg soilA . occidentale L . ６７ 照.４ ５３ �.６ ４８  .８ ４６ 儋.６M . aculeatum Raddi . ３５ 照.９ ３４ �.８ ２８  .８ ２８ 儋.６A . integri f olia L . ７３ 照.３ ６０ �.９ ４８  .２ ４１ 儋.４M . caesalp inii f olia Benth . ３５ 照.６ ３５ �.２ ３８  .０ ３０ 儋.０Shade vs . Sun P ＜ ０ .０００２Legume tree vs . Non‐legume tree P ＜ ０ .０００１Standard error ＝ ４ .６ g of O .M ./ kg of soilTable 2 Mehlich‐I P ( mg / dm3 ) according to a shadegradient under legume and non‐legume trees occurring onsignalgrass pastures , Itambé‐PE , Braz il .Crown projection ( ％ ) Soil Mehlich‐I P ( mg / dm３ )１０ 梃２３ !.４５０ 梃１５ !.９１００  １７ !.０１５０  ９ .７S .E . ６  .３L inear eff ect P ＜ ０ ,.０１７３Shade v s . Sun P ＜ ０ ,.０３５０Conclusions Soil fertility was greater under the crown projection than under full‐sun exposed areas . Greater residue depositionand cattle manure deposition on shaded areas likely contributed to increasing soil fertility levels under trees . Non‐legume treeshad denser and wider crowns , which likely contributed to greater SOM accumulation under the crowns compared to legumetrees .ReferencesEMBRAPA‐Servi毕o Nacional de Levantamento e Conserva毕本o do Solo , ( Rio de Janeiro , R .J .) . １９７９ . Manual de Métodos deAnálise de Solos , parte ３ ,análise e fertilidade . Rio de Janeiro ,１９７９ . １７ p .Dubeux , J .C .B . , JR . ; Sollenberger , L .E . ; Mathews , B .W . ; Scholberg , J .M . ; Santos , H .Q . ２００７ . Nutrient cycling inwarm‐climate grasslands . Crop Sci . , ４７ , p .９１５‐９２８ .

Characterization of Soil Properties under Legume and Non‐Legume Tree Canopies Occurring in Signal Grass (\u3cem\u3eBrachiaria decumbens\u3c/em\u3e Stapf.) Pastures

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=3183&amp;context=igc

Characterization of Soil Properties under Legume and Non‐Legume Tree Canopies Occurring in Signal Grass (\u3cem\u3eBrachiaria decumbens\u3c/em\u3e Stapf.) Pastures

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