Changes in Soil Organic Carbon Fractions in Response to Cover Crops in an Orange Orchard

Abstract

ABSTRACT:The cultivation of cover crops intercropped with fruit trees is an alternative to maintain mulch cover between plant rows and increase soil organic carbon (C) stocks. The objective of this study was to evaluate changes in soil total organic C content and labile organic matter fractions in response to cover crop cultivation in an orange orchard. The experiment was performed in the state of Bahia, in a citrus orchard with cultivar 'Pera' orange (Citrus sinensis) at a spacing of 6 × 4 m. A randomized complete block design with three replications was used. The following species were used as cover crops: Brachiaria (Brachiaria decumbes) -BRAQ, pearl millet (Pennisetum glaucum) -MIL, jack bean (Canavalia ensiformis) -JB, blend (50 % each) of jack bean + millet (JB/MIL), and spontaneous vegetation (SPV). The cover crops were broadcast-seeded between the rows of orange trees and mechanically mowed after flowering. Soil sampling at depths of 0.00-0.10, 0.10-0.20, and 0.20-0.40 m was performed in small soil trenches. The total soil organic C (SOC) content, light fraction (LF), and the particulate organic C (POC), and oxidizable organic C fractions were estimated. Total soil organic C content was not significantly changed by the cover crops, indicating low sensitivity in reacting to recent changes in soil organic matter due to management practices. Grasses enabled a greater accumulation of SOC stocks in 0.00-0.40 m compared to all other treatments. Jack bean cultivation increased LF and the most labile oxidizable organic C fraction (F1) in the soil surface and the deepest layer tested. Cover crop cultivation increased labile C in the 0.00-0.10 m layer, which can enhance soil microbial activity and nutrient absorption by the citrus trees. The fractions LF and F1 may be suitable indicators for monitoring changes in soil organic matter content due to changes in soil management practices.

Decomposition and Nutrient Release Dynamics of Shoot Phytomass of Cover Crops in the Recôncavo Baiano

“…For that reason, combining grass and legume species (a mix of cover crops) during the rainy season is the best strategy. For perennial crops, such as the citrus orchards that are common in the region, it is possible to plant legumes (which biologically fix N) and grasses (which increase the organic C in the soil) between the crops during the rainy season (Oliveira et al, 2016).…”

Estado Nutricional E Produtividade Da Soja Após Aplicação De Calcário E Gesso Com E Sem Revolvimento Do Solo

“…KEYWORDS: Availability, fertility, soil. (RAMOS et al, 2015;BEUTLER et al, 2016;FERREIRA et al, 2016;OLIVEIRA et al, 2016;SILVA et al, 2016;TEIXEIRA et al,2016;SILVA et al, 2017 No local de estudo foram selecionadas cinco áreas distintas, limítrofes, sob as mesmas condições topográfi cas e edafoclimáticas (mesmo solo e clima, textura média, relevo plano), diferenciando-se apenas no uso e manejo adotado. As áreas avaliadas foram: A1 sob mata nativa não disturbada; a A2 área com culturas anuais;…”

Evaluation of the Impact of Citrus Cultivation on Carbon and Nitrogen Stocks of Light Organic Matter Fractions of Amazonian Dark Earth (ADE) and Surrounding Soils (Oxisoil) from Central Amazonia

“…[22][23][24] Além disso, estas concentrações foram aproximadamente três vezes mais elevadas que as obtidas para um Latossolo Amarelo cultivado com Laranja Pêra na Bahia. 1 As concentrações de nitrogênio da TPI foram maiores que os teores encontrados no LA nas três profundidades, tanto na linha quanto na entre linha (Tabela 2). Estas concentrações ao longo do perfil no solo de TPI assemelham-se muito aos que foram encontrados em solos sob floresta secundária, terciária e num solo sob pasto no estado de Rondônia.…”

“…1,2 Esse empobrecimento resulta tanto da retirada de nutrientes do solo pelas colheitas sucessivas, como das degradações físicas ou químicas que podem ocorrer em consequência da erosão, da lixiviação e da compactação do solo. [1][2][3] Os solos predominantes da região Amazônica pertencem às ordens dos Latossolos e dos Argissolos, caracterizados pelo baixo teor de nutrientes, acidez elevada, alta saturação de alumínio, predominância de minerais de argila de baixa atividade, baixa capacidade de troca de cátions e alta quantidade de óxidos e hidróxidos de ferro e alumínio. [3][4][5][6] Porém, na Amazônia existem ainda solos altamente férteis com horizontes superficiais de coloração escura, denominados Terra Preta do Índio (TPI), geralmente com elevados teores de P, Ca, Mg, Zn, Mn e matéria orgânica estável.…”