Biomass residues improve soil chemical and biological properties reestablishing native species in an exposed subsoil in Brazilian Cerrado

Abstract

Revegetation of exposed sub-soil, while a desirable strategy in the recovery processes, often fails due to extreme soil chemical properties, such as low organic matter and pH levels inhospitable to biological activities such as nutrients cycling and plant establishment. This is the case for approximately 800 ha of the Cerrado biome in Brazil, where erecting the embankment of a hydroelectric dam in the 1960’s stripped vegetation, soil, and subsoil layers thereby distorting the soil properties. This work evaluates the effectiveness of restoration management (RM) treatments, to restore the soil quality, including biological activity and chemical attributes. In a factorial scheme, RM treatments include the addition of organic residue from aquatic macrophytes (AM) at 3 rates (0, 16 and 32 t ha-1), combined with ash from sugar cane bagasse of agroindustrial origin (BA) at 4 rates (0, 15, 30 and 45 t ha-1). RM samples contrasted samples collected from undisturbed Cerrado (CER) as well as a degraded area without intervention (DAWI). The mechanized RM plots received amendments and reforestation of 10 Cerrado native tree species. After 5 years, vegetation covered up to 60% of the surface in RM treatments receiving AM32 + BA45. AM and BA residues promoted height increases in the introduced plants. All RM treatments promoted lower levels of Al3+ than DAWI and CER. The combination of AM32 over the rates of incorporated ash increased soil pH and K values similarly to CER. Microbial-related variables, such as microbial biomass-C was the largest in CER, followed by the RM treatments, and the lowest in DAWI. The microbial quotient was no different between CER and RM treatments. The addition of residues such as AM and BA increased the vegetation covered, improved chemical and microbiological indicators. Thus, the residues used aided the recovery process of intensely degraded soils in the Cerrado area.

Post-Harvest Eucalyptus Residue Removal Reduces Soil Aggregation and Biological Activities in Central-West Brazil

“…Considering the proportion of each aggregate size class and their respective TOC concentration, the amount of TOC associated with LM was 57 and 10 times greater than that associated with MI and SM, respectively. The microbial quotients (qMic) can serve as indicators to describe the relationship between the amount of microbial biomass carbon (MBC) and the soil TOC [39,47]. Our results indicate that MI and SM had qMic's around 5.3 times larger than LM.…”

Effect of Microbial Preparation and Biomass Incorporation on Soil Biological and Chemical Properties

“…Biomass incorporation was shown to enrich the soils with carbon and nutrients. Due to the enhanced biological, chemical and physical conditions, these amendments allow the fast recovery of sandy, degraded, and lacking organic matter soils [9][10][11]. The introduction of straw, manure, or catch crop biomass into the soil is a way to manage the excessive amount of organic biomass produced in agriculture, while, at the same time, supplementing the deficits of organic matter in the soil, which is observed especially with a high share of cereals in the sowing structure (Table 1) [12].…”

Evolution of Soil Chemical Fertility in an Area under Recovery for 30 Years with Anthropic Intervention

“…The use of different techniques to recover degraded soils has become more and more frequent. In this regard, the use of waste has been reported as a possibility to reduce costs with mineral fertilizers, in addition to being an alternative for final disposal [6][7][8][9][10][11]. Several types of waste have been used in recovery actions in the Cerrado.…”