10 research outputs found
Copper immobilization by biochar and microbial community abundance in metal-contaminated soils
Biochar (BC) is gaining attention as a soil amendment that can remediate metal polluted soils. The simultaneous effects of BC on copper (Cu) mobility, microbial activities in soil using metallophytes have scarcely been addressed. The objective of this study was to evaluate the effects of biochar BCs on Cu immobilization and over soil microbial communities in a Cu-contaminated soil evaluated over a two-year trial. A Cu-contaminated soil (338 mg kg(-1)) was incubated with chicken manure biochar (CMB) or oat hull biochar (OHB) at rates of 1 and 5% w/w. Metallophyte Oenothera picensis was grown over one season (six months). The above process was repeated for 3 more consecutive seasons using the same soils. The BCs increased the soil pH and decreased the Cu exchangeable fraction Cu by 5 and 10 times (for OHB and CMB, respectively) by increasing the Cu bound in organic matter and residual fractions, and its effects were consistent across all seasons evaluated. BCs provided favorable habitat for microorganisms that was evident in increased microbial activity. The DHA activity was increased in all BC treatments, reaching a maximum of 7 and 6 times higher than control soils in CMB and OHB. Similar results were observed in microbial respiration, which increased 53% in OHB and 61% in CMB with respect to control. The BCs produced changes in microbial communities in all seasons evaluated. The fungal and bacterial richness were increased by CMB and OHB treatments; however, no clear effects were observed in the microbial diversity estimators. The physiochemical and microbiological effects produced by BC result in an increase of plant biomass production, which was on average 3 times higher than control treatments. However, despite being a metallophyte, O. picensis did not uptake Cu efficiently. Root and shoot Cu concentrations decreased or changed insignificantly in most BC treatments. Crown Copyright (c) 2017 Published by Elsevier B.V. All rights reserve
Maize grain production, plant nutrient concentration and soil chemical properties in response to different residue levels from two previous crops
The incorporation of previous crop residues in agricultural management benefits soil fertility, crop production, and environment. However, there is no enough information about maximum residue application level without negative effect over next crop yield. To evaluate maize (Zea mays L.) yield under short-time conservation management with incorporation and/or importation of different residue levels, a biannual rotation experiment was conducted in ash volcanic soil in south-central Chile. The experiment consisted of two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue; from 0 to 21.4 Mg ha−1 for canola and from 0 to 19.0 Mg ha−1 for bean). Previous crop species and residue level affected some nutrients concentrations in grain and plant and some soil chemical properties, without effect in maize yield, which averaged 16.6 Mg ha−1. Bean residue increased Ca and reduced S in maize plant, increasing soil P, Ca, Mg and K (P < 0.05). Maize grain Ca content was positively and proportionally affected by canola residue level and negatively and proportionally affected by bean residue level. All canola residue levels increased soil pH and Mg, but the highest level reduced soil S; soil P concentration increased proportionally with bean residue level. The highest bean residue level increased soil S. Different crop and levels of residue did not affect maize yield but did some plant nutrient concentration, and also affected some soil chemical properties
Canola production and effect on soil chemical properties in response to different residue levels from three biannual crop rotations
Conservation agriculture using crop rotations and residue management is increasingly accepted in conventional agricultural systems. However, the effects on crop productivity and soil properties of different rotations, levels of use, and residue management have yet to be fully understood. Our study considered the effect of three previous crops (bread wheat, durum wheat, and corn) and four levels of residue incorporation (0%, 50%, 100%, and 200%) in a split plot design with four replicates on canola production parameters and soil chemical properties at the end of this crop. Production parameters and soil chemical properties were mostly affected by the previous crop and less by the residue incorporation rates under the conditions of this experiment; however, neither of these factors affected grain yield (ranging from 4.0 to 4.8 Mg ha−1). Canola residue production was higher (9.7%) after the corn crop, regardless of the residue incorporation rate, but the harvest index was lower after this crop. Most of the soil chemical properties were also affected, revealing increased organic matter and exchangeable K when the previous crop was corn and decreased concentrations of the cations with basic reaction when the previous crop was durum wheat
Effects of biochar amendment on wheat production, mycorrhizal status, soil microbial community, and properties of an Andisol in Southern Chile
Biochar (BC) production from agroforestry wastes and mycorrhizal fungi are potentially important agricultural practices for improving crops yields and increasing phosphorus (P) in volcanic soils. This study aimed to test the effect of BC application on wheat biomass and grain yield production, indigenous arbuscular mycorrhizal (AM) fungi propagules and soil microbial community and related to soil quality properties of an Andisol in Southern Chile. Biochars (BCs) were produced from oat hulls (OBC) and pine bark (PBC). Doses of 0, 5, 10, and 20 Mg ha of BCs were applied on soil using wheat as the test crop. Wheat biomass (root and shoot portion) and grain yield, AM root colonization, spore, mycelium density, and glomalin content (glomalin related soil protein, EE-GRSP) were measured and related with soil quality properties such as bulk density, water-stable aggregates (WSA), and water holding capacity (WHC). The OBC had a significantly higher macronutrients content (N, P, K) than PBC. The highest dose of both BCs significantly improved shoot and root biomass and wheat grain yield. Application of 20 Mg ha of OBC and PBC increased AM spore density and root colonization relative to control treatment. In the same way, the BC application significantly affects the AM mycelium density. The results showed that the application of higher BC dose changed the soil microbial community. The use of BCs in this volcanic soil is an effective strategy to increase wheat biomass, increase grain yield production, stimulate the indigenous AM fungi activity, enhance soil quality properties, and increase the sustainability levels of agricultural systems.This study was supported by FONDECYT Projects3120213 and 11140508
Comparative Study between Silvopastoral and Agroforest Systems on Soil Quality in a Disturbed Native Forest of South-Central Chile
Agroforestry systems (AFSs) have gained recognition as a land use strategy to address food security and climate change. They involve intentionally cultivating trees alongside crops and/or animals. AFSs cover approximately 5% of the global forest area and promote sustainable soil conservation, including soil organic carbon (C) sequestration (C-SEQ). In some areas of Chile, AFSs are used to preserve the ecological value of native forests. This study evaluates the effects of two AFSs, namely, an agroforest for fodder production (A(GRO)F(RST)) and Silvopastoral (SPS), within a degraded native forest (Nothofagus obliqua sp.). The evaluation focuses on their impact on CSEQ capacity and soil quality (SQ), using soil quality indexes (SQIs) derived from 30 soil quality indicators (SINDs) related to physical, chemical, and microbiological properties at two depths (0-5 and 5-20 cm). The results for the total depth analyzed (0-20 cm) indicate an average C-SEQ of 6.88 and 4.83 Mg C yr(-1) and a global SQI of 37.8% and 31.0% for A(GRO)F(RST) and SPS, respectively. Among the thirteen SINDs that demonstrated significant differences (p < 0.05), five were associated with the considered depths (P+, Ca2+, S, ECEC, and Al-SAT), three differed between A(GRO)F(RST )and SPS (BD, NH4+, NO3-), while SOC, K+, and Mg2+ varied across all conditions (e.g., combinations of systems and depths), and beta-(GLU) and N-MIN differed in a single condition. However, almost all 30 S-INDs analyzed showed higher values at the 0-5 cm depth, indicating the positive effects of soil organic matter (SOM)/SOC additions. Significant interactions (Pearson's correlation) revealed that SOC correlated with most S-INDs (e.g., N, NH4+, P+, K+, Ca2+, Mg2+, S, ECEC, N-MIN). These findings suggest that both A(GRO)F(RST) and SPS systems have similar capabilities in restoring the ecological value of native Nothofagus forests while providing conditions for productive and complementary use. This sustainable option offers opportunities for cattle production alongside ecological restoration efforts and provides a possible strategy to generate public policies related to the ecosystem services of agroforestry systems
Comparative Study between Silvopastoral and Agroforest Systems on Soil Quality in a Disturbed Native Forest of South-Central Chile
Agroforestry systems (AFSs) have gained recognition as a land use strategy to address food security and climate change. They involve intentionally cultivating trees alongside crops and/or animals. AFSs cover approximately 5% of the global forest area and promote sustainable soil conservation, including soil organic carbon (C) sequestration (CSEQ). In some areas of Chile, AFSs are used to preserve the ecological value of native forests. This study evaluates the effects of two AFSs, namely, an agroforest for fodder production (AGROFRST) and Silvopastoral (SPS), within a degraded native forest (Nothofagus obliqua sp.). The evaluation focuses on their impact on CSEQ capacity and soil quality (SQ), using soil quality indexes (SQIs) derived from 30 soil quality indicators (SINDs) related to physical, chemical, and microbiological properties at two depths (0–5 and 5–20 cm). The results for the total depth analyzed (0–20 cm) indicate an average CSEQ of 6.88 and 4.83 Mg C yr−1 and a global SQI of 37.8% and 31.0% for AGROFRST and SPS, respectively. Among the thirteen SINDs that demonstrated significant differences (p +, Ca2+, S, ECEC, and AlSAT), three differed between AGROFRST and SPS (BD, NH4+, NO3−), while SOC, K+, and Mg2+ varied across all conditions (e.g., combinations of systems and depths), and β-GLU and NMIN differed in a single condition. However, almost all 30 SINDs analyzed showed higher values at the 0–5 cm depth, indicating the positive effects of soil organic matter (SOM)/SOC additions. Significant interactions (Pearson’s correlation) revealed that SOC correlated with most SINDs (e.g., N, NH4+, P+, K+, Ca2+, Mg2+, S, ECEC, NMIN). These findings suggest that both AGROFRST and SPS systems have similar capabilities in restoring the ecological value of native Nothofagus forests while providing conditions for productive and complementary use. This sustainable option offers opportunities for cattle production alongside ecological restoration efforts and provides a possible strategy to generate public policies related to the ecosystem services of agroforestry systems
CHLSOC: the Chilean Soil Organic Carbon database, a multi-institutional collaborative effort
A critical aspect of predicting soil organic carbon (SOC) concentrations is the lack of available soil information; where information on soil characteristics is available, it is usually focused on regions of high agricultural interest. To date, in Chile, a large proportion of the SOC data have been collected in areas of intensive agricultural or forestry use; however, vast areas beyond these forms of land use have few or no soil data available.
Here we present a new SOC database for the country, which is the result of an unprecedented national effort under the framework of the Global Soil Partnership. This partnership has helped build the largest database of SOC to date in Chile, named the Chilean Soil Organic Carbon database (CHLSOC), comprising 13 612 data points compiled from numerous sources, including unpublished and difficult-to-access data. The database will allow users to fill spatial gaps where no SOC estimates were publicly available previously. Presented values of SOC range from 6 x 10(-5) % to 83.3 %, reflecting the variety of ecosystems that exist in Chile.
The database has the potential to inform and test current models that predict SOC stocks and dynamics at larger spatial scales, thus enabling benefits from the richness of geochemical, topographic and climatic variability in Chile.Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)
CONICYT FONDECYT
11160372
Convenio CONAF-UDeC 2015 Perturbaciones Araucaria
ERANet-LAC joint program
ELAC2014/DCC-0092
Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)
CONICYT FONDECYT
1161492
Global Soil Partnership - Food and Agriculture Organization of the United Nations (FAO)
South America Soil Partnership - Food and Agriculture Organization of the United Nations (FAO
CHLSOC: The Chilean Soil Organic Carbon database, a multi-institutional collaborative effort
One of the critical aspects in modelling soil organic carbon (SOC) predictions is the lack of access to soil information which is usually concentrated in regions of high agricultural interest. In Chile, most soil and SOC data to date is highly concentrated in 25 % of the territory that has intensive agricultural or forestry use. Vast areas beyond those forms of land use have few or no soil data available. Here, we present a new database of SOC for the country, which is the result of an unprecedented national effort under the frame of the Global Soil Partnership that help to build the largest database on SOC to date in Chile named “CHLSOC" comprising 13,612 data points. This dataset is the product of the compilation from numerous sources including unpublished and difficult to access data, allowing to fill numerous spatial gaps where no SOC estimates were publicly available before. The values of SOC compiled in CHLSOC range from 6×10−5 to 83.3 percent, reflecting the variety of ecosystems that exists in Chile. Profiting from the richness of geochemical, topographic and climatic variability in Chile, the dataset has the potential to inform and test models trying to predict SOC stocks and dynamics at larger spatial scales.ISSN:1866-359