Impact of land use on Histosols properties in urban agriculture ecosystems of Rio de Janeiro, Brazil

Abstract

Histosols provide several ecosystem services, related mainly to their reserves of carbon and nitrogen. Management practices in these soils can increase the mineralization of organic matter and contribute to the emission of greenhouse gases. This study aimed to investigate the effect of tillage with plowing and drainage on Histosol properties in three land use systems located in the municipality of Rio de Janeiro, Brazil. Three areas subjected to different land use systems over the last twenty years were chosen: Area 1, secondary forest with natural regeneration; Area 2, conventional tillage of cassava with plowing; and Area 3, intercropped coconut + cassava with an artificial drainage system. The chemical characterization, von Post scale of organic matter decomposition, percentage of rubbed fiber, organic matter, percentage of mineral material, bulk density, electrical conductivity, soluble phosphate, total organic carbon (TOC) and nitrogen (NT), organic carbon fractions, and C and N stocks were analyzed. Our results showed the critical, nearly irreversible effects of agricultural practices comprising drainage and plowing of the soil. Over twenty years, in Area 2, the TOC and NT values decreased by 33 and 20 %, respectively in the histic horizon, and by about 17 and 8 %, respectively in the gley horizon. In Area 3, the TOC and NT values decreased by 31 and 18 %, respectively, in the histic horizon, and by 27 and 21 % in the gley horizon. Our findings also showed that the loss of C is related to the labile organic carbon, which is more sensitive to environmental changes, even at deeper depths. The plowing of the soil decreases the organic matter content due to the accelerated oxidation of organic matter, increasing the bulk density. Drainage, besides the loss of organic matter by subsidence, promotes the sulfidization of the soil with a high content of SO 4 2-, due to the oxidation of soil materials containing sulfides.

C:N:P stoichiometry as indicator of Histosol drainage in lowland and mountains forest ecosystem

“…The Histosol subtypes we examined in the current study are characterised by different C/N, C/P and N/P ratios. The lowest ratios were found in the sapric Histosols, which also had the highest pH and a signi cantly higher content of N and P. The low C/N ratio re ects a more intensive decomposition of soil organic matter as well as the quality of this organic matter and the rates of microbial transformation processes (Santos et al 2020). The low C/P and N/P ratio in sapric Histosols con rms the increase of nutrients in soil organic matter in relation to the C content.…”

Is cassava yield affected by inverting tillage, chiseling or additional compaction of no-till sandy-loam soil?

“…Soil chiseling is a tillage method used to reduce surface soil compaction in no-tillage systems by reducing soil bulk density and enhancing pore space (Cavalieri et al, 2006;Klein and Camara, 2007;Fasinmirin and Reichert, 2011;Awe et al, 2020;Reichert et al, 2020a;França et al, 2021;Reichert et al, 2021a;Rosa et al, 2021). Conventional tillage, the traditional tillage method used for cassava (Santos et al, 2020;Thomaz and Fidalski, 2020), is another option for decreasing soil compaction, but the excessive disturbance from soil inverting and mixing by plowing and disking causes undesirable effects such as soil disaggregation, with further exposion to rainfall impact (Lima et al, 2015), especially in sandy soils that are highly prone to erosion (Cantalice et al, 2005;Silva et al, 2020;Thomaz and Fidalski, 2020). In Brazil and elsewhere, the different tillage methods have been evaluated for soil compaction by quantifying the limiting soil bulk density and the performance of several crops (Suzuki et al, 2007;Reinert et al, 2008;Reichert et al, 2009a;Secco et al, 2009;Suzuki et al, 2013;Mentges et al, 2016;Moraes et al, 2019;Reichert et al, 2016aReichert et al, , 2017Reichert et al, , 2018Ambus et al, 2018;Andognini et al, 2020;Reichert et al, 2021a,b).…”