Soil CO2 fluxes in cereal land use of the Spanish plateau: influence of conventional and reduced tillage practices

Abstract. Savanna ecosystems are subject to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO2 fluxes from the soil. We measured methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) over a complete wet-dry seasonal cycle at three replicated sites of each of three land uses: savanna, young pasture and old pasture (converted from savanna 5–7 and 25–30 yr ago, respectively) in the Douglas Daly region of northern Australia. The effect of break of season rains at the end of the dry season was investigated with two irrigation experiments. Land use change from savanna to pasture increased net greenhouse gas fluxes from the soil. Pasture sites were a weaker sink for CH4 than savanna sites and, under wet conditions, old pastures turned from being sinks to a significant source of CH4. Nitrous oxide emissions were generally very low, in the range of 0 to 5 μg N2O-N m−2 h−1, and under dry conditions soil uptake of N2O was apparent. Break of season rains produced a small, short lived pulse of N2O up to 20 μg N2O-N m−2 h−1, most evident in pasture soil. Annual cumulative soil CO2 fluxes increased after clearing, with savanna (14.6 t CO2-C ha−1 yr−1) having the lowest fluxes compared to old pasture (18.5 t CO2-C ha−1 yr−1) and young pasture (20.0 t CO2-C ha−1 yr−1). Clearing savanna increased soil-based greenhouse gas emissions from 53 to ~70 t CO2-equivalents, a 30% increase dominated by an increase in soil CO2 emissions and shift from soil CH4 sink to source. Seasonal variation was clearly driven by soil water content, supporting the emerging view that soil water content is a more important driver of soil gas fluxes than soil temperature in tropical ecosystems where temperature varies little among seasons.

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Soil fertility controls soil–atmosphere carbon dioxide and methane fluxes in a tropical landscape converted from lowland forest to rubber and oil palm plantations

Biogeosciences ◽

10.5194/bg-12-5831-2015 ◽

2015 ◽

Vol 12 (19) ◽

pp. 5831-5852 ◽

Cited By ~ 30

Author(s):

E. Hassler ◽

M. D. Corre ◽

A. Tjoa ◽

M. Damris ◽

S. R. Utami ◽

...

Keyword(s):

Land Use ◽

Soil Fertility ◽

Oil Palm ◽

Co2 Fluxes ◽

Soil Co2 ◽

Soil Atmosphere ◽

Land Use Types ◽

C Stocks ◽

Ch4 Uptake ◽

Tropical Landscape

Abstract. Expansion of palm oil and rubber production, for which global demand is increasing, causes rapid deforestation in Sumatra, Indonesia, and is expected to continue in the next decades. Our study aimed to (1) quantify changes in soil CO2 and CH4 fluxes with land-use change and (2) determine their controlling factors. In Jambi Province, Sumatra, we selected two landscapes on heavily weathered soils that differ mainly in texture: loam and clay Acrisol soils. In each landscape, we investigated the reference land-use types (forest and secondary forest with regenerating rubber) and the converted land-use types (rubber, 7–17 years old, and oil palm plantations, 9–16 years old). We measured soil CO2 and CH4 fluxes monthly from December 2012 to December 2013. Annual soil CO2 fluxes from the reference land-use types were correlated with soil fertility: low extractable phosphorus (P) coincided with high annual CO2 fluxes from the loam Acrisol soil that had lower fertility than the clay Acrisol soil (P < 0.05). Soil CO2 fluxes from the oil palm (107.2 to 115.7 mg C m−2 h−1) decreased compared to the other land-use types (between 178.7 and 195.9 mg C m−2 h−1; P < 0.01). Across land-use types, annual CO2 fluxes were positively correlated with soil organic carbon (C) and negatively correlated with 15N signatures, extractable P and base saturation. This suggests that the reduced soil CO2 fluxes from oil palm were the result of strongly decomposed soil organic matter and reduced soil C stocks due to reduced litter input as well as being due to a possible reduction in C allocation to roots due to improved soil fertility from liming and P fertilization in these plantations. Soil CH4 uptake in the reference land-use types was negatively correlated with net nitrogen (N) mineralization and soil mineral N, suggesting N limitation of CH4 uptake, and positively correlated with exchangeable aluminum (Al), indicating a decrease in methanotrophic activity at high Al saturation. Reduction in soil CH4 uptake in the converted land-use types (ranging from −3.0 to −14.9 μg C m−2 h−1) compared to the reference land-use types (ranging from −20.8 to −40.3 μg C m−2 h−1; P < 0.01) was due to a decrease in soil N availability in the converted land-use types. Our study shows for the first time that differences in soil fertility control the soil–atmosphere exchange of CO2 and CH4 in a tropical landscape, a mechanism that we were able to detect by conducting this study on the landscape scale.

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Land use change and the impact on greenhouse gas exchange in north Australian savanna soils

Biogeosciences ◽

10.5194/bg-9-423-2012 ◽

2012 ◽

Vol 9 (1) ◽

pp. 423-437 ◽

Cited By ~ 36

Author(s):

S. P. P. Grover ◽

S. J. Livesley ◽

L. B. Hutley ◽

H. Jamali ◽

B. Fest ◽

...

Keyword(s):

Land Use ◽

Nitrous Oxide ◽

Land Use Change ◽

Greenhouse Gas ◽

Water Content ◽

Soil Water Content ◽

Co2 Fluxes ◽

Soil Co2 ◽

Gas Fluxes ◽

Greenhouse Gas Fluxes

Abstract. Savanna ecosystems are subjected to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO2 fluxes from the soil. We measured methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) over a complete wet-dry seasonal cycle at three replicate sites of each of three land uses: savanna, young pasture and old pasture (converted from savanna 5–7 and 25–30 yr ago, respectively) in the Douglas Daly region of Northern Australia. The effect of break of season rains at the end of the dry season was investigated with two irrigation experiments. Land use change from savanna to pasture increased net greenhouse gas fluxes from the soil. Pasture sites were a weaker sink for CH4 than savanna sites and, under wet conditions, old pastures turned from being sinks to a significant source of CH4. Nitrous oxide emissions were generally very low, in the range of 0 to 5 μg N2O-N m−2 h−1, and under dry conditions soil uptake of N2O was apparent. Break of season rains produced a small, short lived pulse of N2O up to 20 μg N2O-N m−2 h−1, most evident in pasture soil. Annual cumulative soil CO2 fluxes increased after clearing, with savanna (14.6 t CO2-C ha−1 yr−1) having the lowest fluxes compared to old pasture (18.5 t CO2-C ha−1 yr−1) and young pasture (20.0 t CO2-C ha−1 yr−1). Clearing savanna increased soil-based greenhouse gas emissions from 53 to ∼ 70 t CO2-equivalents, a 30% increase dominated by an increase in soil CO2 emissions and shift from soil CH4 sink to source. Seasonal variation was clearly driven by soil water content, supporting the emerging view that soil water content is a more important driver of soil gas fluxes than soil temperature in tropical ecosystems where temperature varies little among seasons.

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No long-term effect of land-use activities on soil carbon dynamics in tropical montane grasslands

10.5194/bg-2017-113 ◽

2017 ◽

Author(s):

Viktoria Oliver ◽

Imma Oliveras ◽

Jose Kala ◽

Rebecca Lever ◽

Yit Arn Teh

Keyword(s):

Land Use ◽

Organic Matter ◽

Co2 Fluxes ◽

Soil Co2 ◽

Soil C ◽

C Dynamics ◽

Total Soil ◽

C Stocks ◽

Montane Grasslands

Abstract. Montane tropical soils are a large carbon (C) reservoir, acting as both a source and a sink of CO2. Enhanced CO2 emissions originate, in large part, from the decomposition and losses of soil organic matter (SOM) following anthropogenic disturbances. Therefore, quantitative knowledge of the stabilization and decomposition of SOM is necessary in order to understand, assess and predict the impact of land management in the tropics. In particular, labile SOM is an early and sensitive indicator of how SOM responds to changes in land use and management practices, which could have major implications for long term carbon storage and rising atmospheric CO2 concentrations. The aim of this study was to investigate the impacts of grazing and fire history on soil C dynamics in the Peruvian montane grasslands; an understudied ecosystem, which covers approximately a quarter of the land area in Peru. A combination of density and particle-size fractionation was used to quantify the labile and stable organic matter pools, along with soil CO2 flux and decomposition measurements. Grazing and burning together significantly increased soil CO2 fluxes and decomposition rates and reduced temperature as a driver. Although there was no significant effect of land use on total soil C stocks, the combination of burning and grazing decreased the proportion of C in the free LF, especially at the lower depths (10–20 and 20–30 cm). The free LF in the control soils made 20 % of the bulk soil mass and 30 % of the soil C content compared to the burnt-grazed soils, which had the smallest recovery of free LF (10 %) and significantly lower C content (14 %). The burnt soils had a much higher proportion of C in the occluded LF (12 %) compared to the non-burnt soils (7 %) and there was no significant difference among the treatments in the heavy F (~ 70 %). The synergistic effect of burning and grazing caused changes to the soil C dynamics. CO2 fluxes were increased and the dominant temperature driver was obscured by some other process, such as changes in plant C and N allocation promoting autotrophic respiration. In addition, the free LF was negatively affected when these two anthropogenic activities took place on the same site. Most likely a result of reduced detritus being incorporated into the soil. A positive finding from this study is that the total soil C stocks were not significantly affected and the long term C storage in the occluded LF and heavy F were not negatively impacted. Possibly this is because of low intensity fire, fire-resilient grasses and the grazing pressure is below the threshold to cause severe degradation.

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The effects of burning and grazing on soil carbon dynamics in managed Peruvian tropical montane grasslands

Biogeosciences ◽

10.5194/bg-14-5633-2017 ◽

2017 ◽

Vol 14 (24) ◽

pp. 5633-5646 ◽

Cited By ~ 3

Author(s):

Viktoria Oliver ◽

Imma Oliveras ◽

Jose Kala ◽

Rebecca Lever ◽

Yit Arn Teh

Keyword(s):

Land Use ◽

Organic Matter ◽

Co2 Fluxes ◽

Soil Co2 ◽

Soil C ◽

C Dynamics ◽

Total Soil ◽

C Stocks ◽

Montane Grasslands

Abstract. Montane tropical soils are a large carbon (C) reservoir, acting as both a source and a sink of CO2. Enhanced CO2 emissions originate, in large part, from the decomposition and losses of soil organic matter (SOM) following anthropogenic disturbances. Therefore, quantitative knowledge of the stabilization and decomposition of SOM is necessary in order to understand, assess and predict the impact of land management in the tropics. In particular, labile SOM is an early and sensitive indicator of how SOM responds to changes in land use and management practices, which could have major implications for long-term carbon storage and rising atmospheric CO2 concentrations. The aim of this study was to investigate the impacts of grazing and fire history on soil C dynamics in the Peruvian montane grasslands, an understudied ecosystem, which covers approximately a quarter of the land area in Peru. A density fractionation method was used to quantify the labile and stable organic matter pools, along with soil CO2 flux and decomposition measurements. Grazing and burning together significantly increased soil CO2 fluxes and decomposition rates and reduced temperature as a driver. Although there was no significant effect of land use on total soil C stocks, the combination of burning and grazing decreased the proportion of C in the free light fraction (LF), especially at the lower depths (10–20 and 20–30 cm). In the control soils, 20 % of the material recovered was in the free LF, which contained 30 % of the soil C content. In comparison, the burnt–grazed soil had the smallest recovery of the free LF (10 %) and a significantly lower C content (14 %). The burnt soils had a much higher proportion of C in the occluded LF (12 %) compared to the not-burnt soils (7 %) and there was no significant difference among the treatments in the heavy fraction (F) ( ∼  70 %). The synergistic effect of burning and grazing caused changes to the soil C dynamics. CO2 fluxes were increased and the dominant temperature driver was obscured by some other process, such as changes in plant C and N allocation. In addition, the free LF was reduced when these two anthropogenic activities took place on the same site – most likely a result of reduced detritus being incorporated into the soil. A positive finding from this study is that the total soil C stocks were not significantly affected and the long-term (+10 years) C storage in the occluded LF and heavy F were not negatively impacted. Possibly this is because of low-intensity fire, fire-resilient grasses and because the grazing pressure is below the threshold necessary to cause severe degradation.

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Soil CO2 fluxes from direct seeding rice fields under two tillage practices in central China

Atmospheric Environment ◽

10.1016/j.atmosenv.2010.04.045 ◽

2010 ◽

Vol 44 (23) ◽

pp. 2696-2704 ◽

Cited By ~ 12

Author(s):

Cheng-fang Li ◽

Zhi-kui Kou ◽

Jin-hua Yang ◽

Ming-li Cai ◽

Jin-ping Wang ◽

...

Keyword(s):

Rice Fields ◽

Direct Seeding ◽

Central China ◽

Co2 Fluxes ◽

Soil Co2 ◽

Tillage Practices

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Effect of period of sugarcane cultivation on the abundance and distribution of weed seeds in the soil profile

Planta Daninha ◽

10.1590/s0100-83582014000300006 ◽

2014 ◽

Vol 32 (3) ◽

pp. 507-513

Author(s):

R.O. Adereti ◽

F.O Takim ◽

Y.A. Abayomi

Keyword(s):

Land Use ◽

Soil Depth ◽

Seed Banks ◽

Soil Samples ◽

Soil Tillage ◽

Fallow Period ◽

Tillage Practices ◽

Weed Seeds ◽

Seed Distribution ◽

Screen House

An experiment was laid down in a screen house to determine the distribution of weed seeds at different soil depths and periods of cultivation of sugarcane in Ilorin, Nigeria. Soil samples from different depth levels (0-10 cm, 11-20 cm and 21-30 cm) were collected after harvesting of canes from three different land use fields (continuous sugarcane cultivation for > 20 years, continuous sugarcane cultivation for < 10 years after long fallow period and continuous sugarcane cultivation for < 5 years after long fallow period) in November, 2012. One kilogram of the sieved composite soil samples was arranged in the screen house and watered at alternate days. Germinating weed seedlings were identified, counted and then pulled out for the period of 8 months. Land use and soil depth had a highly significant (p £ 0.05) effect on the total number of weeds that emerged from the soil samples. The 010 cm of the soil depth had the highest weed seedlings that emerged. There was an equal weed seed distribution at the 11-20 cm and 21-30 cm depths of the soil. Sugarcane fields which have been continuously cultivated for a long period of time with highly disturbing soil tillage practices tend to have larger seed banks in deeper soil layers (11-20 cm and 21-30 cm) while recently opened fields had significantly larger seed banks at the 0-10 cm soil sampling depth.

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Evaluation of Sustainability of Maize Cultivation in Poland. A Prospect Theory—PROMETHEE Approach

Sustainability ◽

10.3390/su10114263 ◽

2018 ◽

Vol 10 (11) ◽

pp. 4263 ◽

Cited By ~ 8

Author(s):

Aleksandra Król ◽

Jerzy Księżak ◽

Elżbieta Kubińska ◽

Stelios Rozakis

Keyword(s):

Prospect Theory ◽

Reduced Tillage ◽

Small Farm ◽

Tillage Practices ◽

Maize Cultivation ◽

Long Term Experiment ◽

Promethee Method ◽

Large Farm ◽

Alternative Practices ◽

Direct Sowing

This study aims at exploiting research outcomes concerning tillage practices in order to make solutions available to farmers to mitigate negative environmental impact to soils. Two alternative practices have been analysed against conventional full tillage based on data provided by a long-term experiment conducted at the Institute of Soil Science and Plant Cultivation (IUNG) farm in Grabów, Central Poland. Reduced Tillage and Direct Sowing are evaluated against Full Tillage on the basis of socio-economic and environmental criteria. Multi-criteria decision analysis undertaken using the PROMETHEE method provided evidence that the ‘optimal’ maize cultivation system depends on the decision maker’s viewpoint and preferences. In fact, criteria selected and related weights elicited from representative farmers, as well as from an expert agronomist, reveal different viewpoints. Direct sowing was the most preferable for the large farm and expert perspective, whereas in case of small farm reduced tillage ranked first. Prospect theory developed by behavioural economists was incorporated to take into account decision biases. As a matter of fact, based on Prospect Theory-PROMETHEE from the small farm and the expert perspective, the conventional system was now ranked first, while for the large farm, the most preferable practice was still direct sowing.

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