Temporal and spatial variation of soil respiration under mulching in a greenhouse cucumber cultivation

Abstract

-The objective of this work was to determine the temporal and spatial variations of soil respiration (Rs) in a greenhouse, as well as the factors causing them, in a soil covered with different mulching types and cultivated with cucumber (Cucumis sativus). Four mulching treatments were applied to a soil cultivated with cucumber: CK, conventional practice without mulch; FM, plastic film mulch; CM, combined mulch of plastic film with wheat straw; and SM, wheat straw mulch. Rs was measured by a soil respiration chamber connected to a portable infrared gas analyzer, and the differences of Rs between mulchings were evaluated. Rs was significantly lower in the control than in the treatments with mulch. In addition, Rs was higher in the position on the soil near plants (5.4 µmol CO 2 m -2 s -1 ) than in the positions between plants (4.7 µmol CO 2 m -2 s -1 ) and rows (3.9 µmol CO 2 m -2 s -1 ). Soil water content and temperature had an interacted effect on Rs. Cucumber root biomass and root vigor should also be incorporated as predictor variables for Rs in the succession crops, mainly for accurately estimating carbon cycling in agroecosystems in a greenhouse.Index terms: Cucumis sativus, climate change, soil CO 2 emission, soil quality.Variação temporal e espacial da respiração do solo sob cobertura em cultivo de pepino em estufaResumo -O objetivo deste trabalho foi determinar as variações temporais e espaciais da respiração do solo (Rs) em casa de vegetação, assim como os fatores que as causam, em um solo com diferentes coberturas, cultivado com pepino (Cucumis sativus). Quatro tratamentos de cobertura foram aplicados ao solo cultivado com pepino: CK, prática convencional sem cobertura; FM, cobertura com filme plástico; CM, cobertura com filme plástico e palha de trigo; e SM, cobertura com palha de trigo. A Rs foi medida por meio de uma câmara de respiração de solo, conectada a um analisador de gás infravermelho, e as diferenças de Rs entre as coberturas foram avaliadas. A Rs foi significativamente menor no controle do que nos tratamentos com cobertura. Além disso, a Rs foi mais elevada nas posições de solo próximas das plantas (5,4 µmol CO 2 m -2 s -1 ) do que nas posições entre plantas (4,7 µmol CO 2 m -2 s -1 ) e entre linhas (3,9 µmol CO 2 m -2 s -1 ). O teor de água no solo e a temperatura do solo apresentaram efeito interativo sobre a Rs. A biomassa e o vigor radiculares do pepino devem ser incorporados como variáveis preditoras de Rs nos cultivos em sucessão, principalmente para a estimação acurada do ciclo do carbono em agroecossistemas, em casa de vegetação.Termos para indexação: Cucumis sativus, mudanças climáticas, emissão de CO 2 do solo, qualidade do solo.

Effects of biodegradable plastic film mulching on soil microbial communities in two agroecosystems

“…These studies provide insight into the potential of these enzymes in the degradation process of BDMs. Other studies that have looked at more general activity responses by microbes under plastic mulches (i.e., respiration) have reported mixed results: some have observed increases in activity under plastic mulches (Chen et al, 2017;Mu, Fang & Liang, 2016;Mu et al, 2014;Zhang et al, 2015), while others report decreased activities (Moreno & Moreno, 2008).…”

Biodegradable Plastic Mulch Films: Impacts on Soil Microbial Communities and Ecosystem Functions

“…In addition to changes in microbial community structure, plastic film mulches affect microbial functioning. Some studies report increased microbial activity under mulches ( Mu et al, 2014 , 2016 ; Zhang et al, 2015 ; Chen H. et al, 2017 ), while others report decreased activity ( Moreno and Moreno, 2008 ). The response is most likely dependent on the amount of warming under the mulches: where ambient temperatures are cool, mulches bring soil temperature closer to microbial optima and increase activity, whereas in warmer seasons, the mulches may push temperatures above optima, limiting soil microbial activity ( Moreno and Moreno, 2008 ).…”

Structural and Functional Responses of Soil Microbial Communities to Biodegradable Plastic Film Mulching in Two Agroecosystems

“…Other studies that have looked at more general activity responses by microbes under plastic mulches (i.e. respiration) have reported mixed results: some have observed increases in activity under plastic mulches (68–71), while others report decreased activities (57).…”