Printer Friendly

Ratio of C[O.sub.2] and [O.sub.2] as index for categorising soil biological activity in sugarcane areas under contrasting straw management regimes.

Introduction

Measurements of oxygen flux (F[O.sub.2]) in soils are related to the metabolic status of microorganisms and carbon accumulation or loss, especially in environments where these processes are driven by aerobic microbial activity (Stern et al. 1999), considering F[O.sub.2] as a reflection of carbon dioxide flux (FC[O.sub.2]) in the global carbon cycle (Keeling and Shertz 1992; Dilly 2003).

The FC[O.sub.2] is considered to be the result of biochemical processes in soil, and is directly related to the respiration of roots and decomposition of organic matter through microbial activity (Lai 2009). It is estimated that for a mixed hardwood forest ecosystem, root respiration accounts for 14--21% of FC[O.sub.2], with the remaining fraction due to the biological activity of soil microorganisms (Melillo et al. 2002). It is noteworthy that FC[O.sub.2] can also result from chemical activities in soil (calcareous and urea reaction; Angert et al. 2015), and processes of degassing of the soil solution and C[O.sub.2] desorption from the solid phase can produce soil C[O.sub.2] efflux (Smagin et al. 2016).

The relationship between FC[O.sub.2] and F[O.sub.2], known and described by Angert et al. (2015) as apparent respiratory quotient (ARQ), is an alternative means of describing and categorising soil activities (chemical, physical and biological), where there is a strong relationship between C[O.sub.2] production and [O.sub.2] consumption. Values of ARQ that are higher or lower than 1 can be interpreted as an imbalance between C[O.sub.2] production and [O.sub.2] consumption as a response to chemical and physical activities in soil (Linn and Doran 1984).

The soil pore network characteristics and soil texture directly influence FC[O.sub.2] and F[O.sub.2] exchange between soil and the atmosphere, through the presence of empty spaces between soil particles and aggregates (Chen et al. 2011). Furthermore, water and nutrient availability (Almeida et al. 2015), and tillage management (Bicalho et al. 2014), can also influence C[O.sub.2] production and transport, as well as [O.sub.2] consumption in soil.

Sugarcane can mechanically harvested with removal or burning of the straw or with maintenance of straw on soil without burning (De Figueiredo and La Scala 2011). Brazil is currently the largest sugarcane producer globally, with an average of 74.1 Mg [ha.sup.-1] biomass yield annually (Conab 2014), and 20 Mg [ha.sup.-1] of resulting residues are retained on the soil surface following harvest (Urquiaga et al. 1991; Oliveira et al. 1999).

The study aimed to (i) examine the profile and relationship between FC[O.sub.2] and F[O.sub.2] in a sugarcane area under contrasting management regimes (mechanical harvesting with straw burning versus mechanical harvesting with maintenance of straw), considering soil moisture; (ii) and suggest the use of ARQ as an index for categorising biological activity in soil.

Material and methods

Characterisation of the study area

The study was conducted in an area under sugarcane (Saccharum spp.) cultivation located in the state of Mato Grosso do Sul, near the municipality of Aparecida do Taboado (20[degrees]19'S and 51[degrees]13'W), Brazil, during 4-14 July 2014. The soil was classified as a dystrophic Red-Yellow Latossolo (Embrapa 2014) and Oxisol (Soil Survey Staff 2014), with a sandy clay loam texture across the 0-0.2 m depth layer (Table 1).

The region has a tropical humid climate classified as Aw (Peel et al. 2007), characterised by a rainy summer (September-June) and a dry winter (June-August), with an average annual rainfall of 1595 mm. During the field measurements, there were two precipitation events on 13 and 14 July with a daily rainfall of 6.1 and 1.5 mm, respectively (Climate Channel at UNESP Ilha Solteira, http://clima.feis.unesp.br).

The effect of residue management was evaluated in two sections of the production field under contrasting straw management regimes (Sections): Section 1, mechanical harvesting with straw burning (BH) and Section 2, mechanical harvesting with maintenance of straw (GH). Normally, GH adds an average of 20 Mg [ha.sup.-1] of crop residue; however, the quantity depends on the variety and the harvest stage (Correia and Durigan 2004; Tofoli et al. 2009; Almeida et al. 2014). Both sections had a sugarcane productivity of 63 and 46 Mg [ha.sup.-1] in 2013 and 2014, respectively.

The study area was 21.77 ha cultivated with the CTC variety of sugarcane, at a population density of 60 000 [ha.sup.-1]. This area has been used for sugarcane production for 20+ years. The soil was prepared and sugarcane planted using the conventional system (soil disturbance) in 2012.

Fertilisation was performed along the furrow and involved the distribution of 250 kg [ha.sup.-1] of mono-ammonium phosphate, equivalent to 120 kg [ha.sup.-1] of [P.sub.2][O.sub.5] and 27 kg [ha.sup.-1] of N-N[H.sub.4.sup.+]. Subsequently, topdressing was done using a liquid formula 05-00-13 + 0.3% Zn + 0.3% B, in the amount of 1000 L [ha.sup.-1], equivalent to 50 kg [ha.sup.-1] N, 130 kg [ha.sup.-1] of [K.sub.2]O, 3 kg [ha.sup.-1] of Zn and B, respectively. After the first cutting, ratoon fertilisation was performed using the best management practices of applying 90kg [ha.sup.-1] N, 30kg [ha.sup.-1] of [P.sub.2][O.sub.5] and 110kg [ha.sup.-1] of[K.sub.2]O.

For the BH, sugarcane was harvested mechanically, with burning; for the GH, the harvest was also mechanical but without burning. At sampling time, the sugarcane plants were ~20 cm tall at 2 weeks after their second cutting (harvest). Therefore, the area did not include plants that displayed higher growth stages.

Field sampling was done by selecting 10 points that had at least 5 m spacing from within each management treatment, and within the four central lines of each plot. The results of soil testing from the two sections (0-0.2 m layer), including soil physical (sand, silt and clay) and chemical properties (pH, soil organic matter, phosphorus, sulfur, calcium, potassium, magnesium, aluminium and cation exchange capacity), as well as the soil porosity (macroporosity, microporosity and total porosity), are shown in Table 1. These measures were determined using methodology from Embrapa (1997).

Water-filled porosity (WFP) was calculated using Eqn 1 described by Linn and Doran (1984). Where, soil moisture was the volumetric water content (%) and the total soil porosity (TP, %) was calculated by TP-(1 - PB/PP) x 100, where the soil particle density (PP) is assumed to be 2.65 Mg [m.sup.-3] and soil bulk density (PB) is in Mg [m.sup.-3].

%WFP = (soil moisture/TP) x 100 (1)

PVC rings (10 cm in diameter and 8.5 cm in height) were previously installed and fixed at the sample points. After 24 h, FC[O.sub.2] and F[O.sub.2] were collected along with data describing soil moisture and temperature for six separate measurement days (4, 6, 8, 10, 12 and 14 July). We used this period because we wanted to observe the relationship between these variables and the soil without the confounding contribution from crop growth at later stages. Soil measurements were made during 07:00-08:00 hours.

To collect FC[O.sub.2] we used an IRGA (LI-COR Inc, Lincoln, NE, USA) with a closed circulation system, an internal volume of 854 mL and a soil contact area of 84 c[m.sup.2]. The IRGA had an infrared (IR) system that measured the C[O.sub.2] concentration using optical-IR absorption spectroscopy. The soil temperature was monitored using a temperature probe that was integrated into the IRGA system.

The soil moisture was measured using a portable Time Domain Reflectometry system (Hydrosense[TM]; Campbell Scientific, Garbutt, Australia) that determined the soil moisture according to the dielectric constant of the travel time for an electromagnetic pulse across the space separating the two end points (two rods, 12 cm high) inserted into the soil adjacent to the PVC ring (0-10 cm).

The soil F[O.sub.2] was monitored using an [O.sub.2] sensor (CM-021; C[O.sub.2] Meter Inc., Ormond Beach, FL, USA) with a full-scale span of 0-25% (v/v). This sensor was portable and utilised ultraviolet light fluorescence to assess the [O.sub.2] concentration. The sensor result was read using Gaslab software to calculate the soil [O.sub.2] uptake rate. With the C[O.sub.2] and [O.sub.2] results, we calculated the ARQ (mol [mol.sup.-1]) according to Wolinska et al. (2011), where the ARQ is a ratio of the C[O.sub.2] emission and [O.sub.2] uptake.

Estimation of soil F[O.sub.2]

Soil F[O.sub.2] rate (d[O.sub.2]/dt) was calculated by a linear interpolation of the concentration values as a function of time, taking into account the atmospheric pressure, temperature and volume of the gas trapped in the chamber, using Eqn 2 as described by Smagin et al. (2016) and Smagin (2006):

F[O.sub.2](g x [m.sup.-2][s.sup.-1]) d[O.sub.2][10.sup.-6]PM/dt RT H (2)

where, d[O.sub.2]/d/ is the amount of [O.sub.2] (ppm) measured at time t (s); P is atmospheric pressure (Pa); M is [O.sub.2] molar mass (g [m.sup.-3]); R is the universal gas constant (8.31 J [mol.sup.-1] [k.sup.-1]); T is absolute temperature (K) and H= V/A: for volume (V)=0.00066 [m.sup.3] and cross-sectional area (A) = 0.008 [m.sup.2] of the camera above the ground (soil surface).

Data processing and statistical analysis

Soil moisture, [O.sub.2] uptake (F[O.sub.2]), C[O.sub.2] emission (FC[O.sub.2]) and the daily mean of ARQ were calculated using an N (number) of 10 replicates per day, compared using Student's t-test (P [less than or equal to] 0.05) per each management sector. Consequently, FC[O.sub.2], F[O.sub.2] and total ARQ were calculated using all days observed, with N= 60 per treatment. An integration of the area under the FC[O.sub.2] and F[O.sub.2] curves was calculated. Thereafter, the treatment results were compared using Student's t-test (P [less than or equal to] 0.05).

The relationships of F[O.sub.2] and FC[O.sub.2] with soil moisture were calculated using Pearson's correlation for both management regimes. The analysis of presuppositions was conducted using analysis of residuals, identifying the outliers and influent values using leverage statistics. The normality of residuals was verified by the Shapiro-Wilk test (P [less than or equal to] 0.05) and homogeneity of variance was assessed using the Bartlett test (P [less than or equal to] 0.05).

Results

Daily results of soil variables

Soil C[O.sub.2] emission on 4, 6, 8 and 10 July were similar, with means of 0.04, 0.06, 0.03 and 0.04 mg [m.sup.-2] [s.sup.-1] for GH and 0.07, 0.07, 0.06 and 0.07 mg [m.sup.-2] [s.sup.-1] for BH respectively (Fig. Id). Both treatments, presented lower and relatively constant C[O.sub.2] emission when the soil moisture varied within 6.44-8.60% (BH) and 6.0-7.4% (GH), (Fig. 1b). However, after 10 July, C[O.sub.2] emission and soil moisture increased by means of 0.07 and 0.14 mg [m.sup.-2] [s.sup.-1] and 14.11 and 14.33% respectively for GH and BH (Fig. 1 d, b), following a precipitation event of 6.1mm (Fig. 1a).

The BH provided higher C[O.sub.2] emission across all days observed, and significantly differed from those of GH on the 4, 8, 10, 12 and 14 July. The highest BH difference was on 12 July with a C[O.sub.2] emission increase of 53.68% compared with GH (Fig. 1 d).

The temporal variability in soil [O.sub.2] uptake was inverse compared with C[O.sub.2] emission the estimates of [O.sub.2] uptake revealed variation of 0.22-0.46 and 0.20-0.40 mg [m.sup.-2] [s.sup.-1] on the first days (4 and 10 July), and following the precipitation event the [O.sub.2] uptake decreased (without a significant difference between the days and treatments) (Fig. 1c).

The ARQ profile was very similar to the estimates of C[O.sub.2] emission, soil moisture and precipitation (Fig. 1). In other words, ARQ was constant, lower than 1 and mean variation range of 0.27-0.90 (GH) and 0.17-0.31 (BH) during 4-10 July. Contrastingly, following the precipitation event (12 July) ARQ was higher than 1, with the greatest values for ARQ in BH (1.38 [+ or -] 0.46 mol [mol.sup.-1]) and lower than 1 in GH (0.77 [+ or -] 0.46 mol [mol.sup.-1]).

Accumulated FC[O.sub.2], F[O.sub.2] and ARQ

Accumulated F[O.sub.2] revealed means of 202.52 [+ or -] 49.62 and 267.41 [+ or -] 73.6 g [O.sub.2] [m.sup.-2] for the GH and BH regimes respectively (Fig. 2a). Comparison by t-test showed no differences in the F[O.sub.2] uptake between harvesting techniques (P>0.05). However, BH demonstrated higher cumulative C[O.sub.2] emission (87.07 [+ or -] 19.45 g C[O.sub.2] [m.sup.-2]), which was 50.0% higher but not significantly different compared with GH (52.31 [+ or -] 15.41 g C[O.sub.2] [m.sup.-2]) (Fig. 2a).

The cumulative ratio of FC[O.sub.2] and F[O.sub.2], represented by ARQ, was below 1 in both treatments, having means of 0.23 [+ or -] 0.18 and 0.18 [+ or -] 0.07 for BH and GH respectively (Fig. 2b). The ARQs for both treatments did not significantly differ according to t-test.

Relationships of soil C[O.sub.2] emission and [O.sub.2] uptake with soil moisture

The C[O.sub.2] emission and soil moisture were positively and significant correlated for both treatments (Fig. 3a, c), although higher for BH (r=0.74) than for GH (r=0.50). The higher r for BH suggests a greater sensitivity of burned residue management. The soil moisture was negatively correlated with [O.sub.2] uptake in BH (r=-0.43) and GH (r = -0.42) (Fig. 3b, d). The C[O.sub.2] and [O.sub.2] were negatively correlated for BH (r=-0.41), but not correlated for GH (Fig. 4). We also noted that GH had a higher microporosity (31.6%) and lower macroporosity (11.1%) and WFP (18.73%) compared with BH (Table 1).

Discussion

C[O.sub.2] and [O.sub.2] results

The consistent magnitude of FC[O.sub.2] across 4-10 July for GH and BH suggests a corresponding stability in soil microbial activity. Typically, low and stable FC[O.sub.2] occurs after the soil carbon mineralisation of soil organic matter (Cunha et al. 2011; Badia et al. 2013; Knicker et al. 2013) leading to lower emissions and microbial activity (Luo et al. 2006).

Higher C[O.sub.2] emission for BH compared with GH has been observed in other studies by Panosso et al. (2009) and Corradi et al. (2013), who examined a similar Oxisol and soil management regimes in Sao Paulo. This difference could be explained by higher nutrient availability in the BH treatment due to burning (Marques et al. 2009; Panosso et al. 2011). However, in our experiment we did not observe a significant difference in soil nutrient availability between BH and GH. This is likely to be driven by the fact the burning occurred once, and that changes to organic nutrient availability through this process depend upon the intensity and duration of burning.

Contrastingly, the BH had higher macroporosity and total porosity, and lower microporosity, compared with GH. The high porosity for BH may have resulted from burning of sugarcane residue and an increase in empty spaces in soil, causing the opening of potentially charred root channels or plugging of smaller micropores by ash deposits. It should be kept in mind that both the BH and GH treatments had the same degree of mechanical harvesting traffic and soil preparation.

The relationship between soil porosity and C[O.sub.2] has been previously reported (Xu and Qi 2001; Epron et al. 2006; Panosso etal. 2011; Bicalho etal. 2014). Soil porosity is responsible for soil gaseous transport (Xu and Qi 2001; Epron et al. 2006) and the movement of organic and inorganic solutions throughout the soil, which supports the natural habitat for microbial communities (Ranjard and Richaume 2001). Therefore, soil porosity can help to explain the degree of soil C[O.sub.2] emission (Wick etal. 2012).

Additionally, the lower FC[O.sub.2] estimates for GH were likely the result of sugarcane residues on the soil surface, which have been shown to present a high carbon/nitrogen ratio (Almeida et al. 2015), lignin (Costa et al. 2013) and cellulose contents (Almeida et al. 2009), and a lower crude protein concentration (Pereira et al. 2000). These characteristics are important parameters in nutrient dynamics (Lai 2004) and can consequently reduce FC[O.sub.2] because of slow residue decomposition (Almeida et al 2014).

Relationships between soil C[O.sub.2] and [O.sub.2]

The temporal variability in soil [O.sub.2] was inverse compared with C[O.sub.2], reflected by a decrease in [O.sub.2] and an increase in C[O.sub.2] for both treatments, following precipitation. Consequently, these results confirm that soil moisture can change the soil C[O.sub.2] and [O.sub.2] profile. According to Gardini et al. (1991) and Howard and Howard (1993), soil moisture is a key abiotic factor affecting the C[O.sub.2] emission and [O.sub.2] uptake processes (Gardini et al. 1991), as well as soil temperature (Kyaw Tha Paw et al. 2006).

The positive correlation between C[O.sub.2] and soil moisture was also observed by Lai (2009) and Wei et al. (2014), and can be described as linear response with respect to soil moisture (variations of 38-47%) at clay soil (Corradi et al. 2013). Soil moisture can promote increases in FC[O.sub.2] of up to 80% (Chen et al. 2011) as result of higher microorganism and root activity (Lai and Kimble 1997). According to Doran et al. (1990) and Chen et al. (2011) the highest soil respiration rates occur for WFP of 40-70% for the majority of soils. In our experiment, there was WFP <70% for all treatments and days observed.

Additionally, the high correlation between FC[O.sub.2] and soil moisture for BH can be explained by higher macroporosity and lower microporosity, which has been shown to govern C[O.sub.2] transport rates and water infiltration in soil aggregations (Silva et al. 2005), and is typically faster in soils with higher macroporosity than microporosity (Ceddia et al. 1999).

Decreases in [O.sub.2] following precipitation events were also observed by Linn and Doran (1984) and Gardini et al. (1991), and have been explained by a reduction in the amount of [O.sub.2] in soil pores with water infiltration (Cook et al. 2007), which limits the [O.sub.2] exchange between soil and atmosphere (Armstrong and Drew 2002; Elberling et al. 2011). This suggests that water in soil pores limits [O.sub.2] uptake, but may increase C[O.sub.2] release for WFP <70%.

Relationships between soil C[O.sub.2] emission and [O.sub.2] uptake

The FC[O.sub.2] and F[O.sub.2] were negatively correlated for the BH treatment. However, we did not observe a relationship between these factors for the GH treatment. Kyaw Tha Paw et al. (2006) also found a negative relationship between FC[O.sub.2] and F[O.sub.2] in soil (at 15 cm in depth) with vegetation of ~3cm high, as consequence of respiration by roots and microorganisms and the simultaneous increase of FC[O.sub.2] concentration and [O.sub.2] depletion. We further observed that F[O.sub.2] was higher than FC[O.sub.2] for both treatments and, similarly, Angert et al. (2015) found higher F[O.sub.2] compared with C[O.sub.2] in a study of temperate and alpine forest ecosystems.

To understand ARQ as an index for categorising soil activity, it must first be understood that ARQ values close to 1 are considered a reflection of aerobic activity with ARQ balance-the result of production of 1 mol C[O.sub.2] and consumption of 1 mol of [O.sub.2]. However, ARQ values higher or lower than 1 indicate an imbalance between FC[O.sub.2] and F[O.sub.2]. The ARQ index has similarly been used as a criterion for soil microbial activity across different WFP conditions (Stotzky 1960; Alef 1995; Dilly 2003), as a means of elucidating the relationship between FC[O.sub.2] and F[O.sub.2].

The ARQ was below 1 before the rainfall event for BH and GH, but shifted closer to 1 after precipitation (12 July) with soil moisture in the range of 6.4-14.5% and WFP <32.0%. According to Linn and Doran (1984), an increase in ARQ values of 1.3-1.7 can occur with an increase in soil water content and WFP >70% and indicates a shift towards anaerobic metabolism. However, in our experiment the WFP value was not >70% on 12 July. Franzluebbers (1999) highlighted that the maximum respiratory activity of soil microbial biomass at WFP levels in the range of 27-68% was due to higher availability of [O.sub.2]. Under this WFP condition, it is likely that there was a predominance of aerobic compared with anaerobic respiration, soil chemical reactions (presence of calcareous materials and urea fertilisation) and the degassing process. According to Smagin et al. (2016), processes of degassing of the soil solution and C[O.sub.2] desorption from the solid phase can produce soil C[O.sub.2] efflux. Therefore, these processes can produce C[O.sub.2] with no direct

relationship to [O.sub.2] consumption, thus changing the soil C[O.sub.2] and [O.sub.2] balance.

Conclusion

Our results show that soil moisture affected the [O.sub.2] uptake and C[O.sub.2] emission profile of soil by limiting [O.sub.2] uptake and increasing the release of C[O.sub.2] for conditions of WFP < 70%. The high level of soil macroporosity and low degree of soil microporosity increased C[O.sub.2] emission.

The correlation between [O.sub.2] uptake and C[O.sub.2] emission profiles depends on crop residue management and soil pore network characteristics. The BH management regime provided higher cumulative C[O.sub.2] emission with a 50.0% increase compared with GH, which added sugarcane residue to the superficial soil layers and so helped prevent soil erosion.

The ARQ can be used as an index to categorise biological activity in soil, with ARQ values close to 1 considered a reflection of aerobic activity with balance between C[O.sub.2] production and [O.sub.2] consumption.

Conflicts of interest

The authors declare no conflicts of interest.

https://doi.org/10.1071/SR16344

Acknowledgements

The authors would like to thank the following Brazilian institutions for their financial support: Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) and Brazilian National Council for Scientific and Technological Development (CNPQ). Many thanks to the Exact Sciences Department (Universidade Estadual Paulista), and to the Soil, Water and Climate Department (University of Minnesota) for the opportunity to develop this paper.

References

Alef K (1995) Soil respiration. In 'Methods in applied soil microbiology'. (Eds K Alef, P Nannipieri) pp. 214-219. (Academic Press: London)

Almeida D, Klauberg Filho O, Felipe AF, Almeida HC (2009) Carbono, nitrogenio e fosforo microbiano do solo sob diferentes coberturas empomar de producao organica de maca no sul do Brasil. Bragantia 68, 1069-1077. doi:10.1590/S0006-87052009000400028

Almeida RF, Silveira CH, Mikhael JE, Franco FO, Ribeiro BT, Ferreira AS, Mendon9a ES, Wendling B (2014) C[O.sub.2] emissions from soil incubated with sugarcane straw and nitrogen fertilizer. African Journal of Biotechnology 13, 3376-3384.

Almeida RF, Silveira CH, Mota RP, Moitinho M, Arruda EM, Mendonja ES, La Scala N, Wendling B (2015) For how long does the quality and quantity of residues in the soil affect the carbon compartments and C[O.sub.2]-C emissions? Journal of Soils and Sediments 16, 1-11.

Angert A, Yakir D, Rodeghiero M, Preisler Y, Davidson EA, Weiner T (2015) Using [O.sub.2] to study the relationships between soil C[O.sub.2] efflux and soil respiration. Biogeosciences 12, 2089-2099. doi: 10.5194/bg-122089-2015

Armstrong W, Drew MC (2002) Root growth and metabolism under oxygen deficiency. In: 'Plant roots: the hidden half. 3rd edn. (Eds Y Waisel, A Eshel, U Kafkafi) pp. 729-761. (CRC Press: New York)

Badia D, Marti C, Aguirre AJ (2013) Residue management effects on C[O.sub.2] efflux and C storage in different Mediterranean agricultural soils. The Science of the Total Environment 465,233-239. doi: 10.1016/j.scitotenv. 2013.04.006

Bicalho ES, Panosso AR, Teixeira DDB, Miranda JGV, Pereira GT, La Scala N (2014) Spatial variability structure of soil C[O.sub.2] emission and soil attributes in a sugarcane area. Agriculture. Ecosystems & Environment 189, 206-215. doi:10.1016/j.agee.2014.03.043

Ceddia MB, Anjos LHC, Lima E, Ravelli Neto A, Silva LA (1999) Sistemas de colheita da cana-de-ajucar e alteragoes nas propriedades fisicas de um solo podzolico amarelo no estado do Espirito Santo. Pesquisa Agropecudria Brasileira 34, 1467-1473. doi: 10.1590/S0100-204X199 9000800019

Chen X, Dhungel J, Bhattarai SP, Torabi M, Pendergast T. Midmore DJ (2011) Impact of oxygation on soil respiration, yield and water use efficiency of three crop species. Journal of Plant Ecology 4, 236-248. doi: 10.1093/jpe/rtq030

Conab (2014). Acompanhamento da safra brasileira: cana-de-afucar, primeiro levantamento. Available at: <http://www.conab.gov.br/Olalacms/uploads/arquivos/13_04_09_10_29_31_boletim_cana_portugues_abril_2013_1 oJev.pdfx Accessed 10 March 2017.

Cook FJ, Knight DJH, Kelliher FM (2007) Oxygen transport in soil and the vertical distribution of roots. Australian Journal of Soil Research 45, 101-110. doi: 10.1071 /SR06137

Corradi MM, Panosso AR, Martins Filho MV, Scala NL Junior (2013) Crop residues on short-term C[O.sub.2] emissions in sugarcane production areas. Engenharia Agricola 33, 699-708. doi: 10.1590/S0100-6916201 3000400009

Correia NM, Durigan JC (2004) Emergencia de plantas daninhas em solo coberto com palha de cana-de-afiicar. Planta Daninha 22, 11-17. doi: 10.1590/S0100-83582004000100002

Costa SM, Mazzola PG, Silva JCAR, Pahl R, Pessoa A Jr, Costa SA (2013) Use of sugar cane straw as a source of cellulose for textile fiber production. Industrial Crops and Products 42, 189-194. doi:10.1016/ j.indcrop.2012.05.028

Cunha EQ, Stone LF, Ferreira EPB, Didonet AD, Moreira JAA, Leandro WM (2011) Sistemas de preparo dosolo e culturas de cobertura na produjao organica de feijao e Milho. II--Atributos biologicos do solo. Revista Brasileira de Ciencia do Solo 35, 603-611. doi: 10.1590/S010006832011000200029

Dilly O (2003) Regulation of the respiratory quotient of soil microbiota by availability of nutrients. Microbial Ecology 43, 375-381. doi: 10.1111/ j.1574-6941.2003.tb01078.x

Doran JW, Mielke LN, Powe JF (1990) Microbial activity as regulated by soil water filled pore space (Transactions of the 14th International Congress on Soil Science, Kyoto, Japan. 3), pp. 94-99.

Elberling B, Askaer L, Jorgensen CJ, Joensen HP, Keuhl M, Glud RM, Lauritsen FR (2011) Linking soil [O.sub.2], C[O.sub.2], and C[H.sub.4] concentrations in a wetland soil: implications for C[O.sub.2] and C[H.sub.4] fluxes. Environmental Science & Technology 45, 3393-3399. doi: 10.1021/es 103540k

Embrapa (1997) 'Manual de metodos de analise de solo.' 2nd edn. (Embrapa: Rio de Janeiro)

Embrapa (2014) 'Manejo Brasileiro de Classificafao do solo.' 3rd edn (Embrapa: Rio de Janeiro)

Epron D, Bosc A, Bonal D, Freycon V (2006) Spatial variation of soil respiration across a topographic gradient in a tropical rain forest in French Guiana. Journal of Tropical Ecology 22, 565-574. doi: 10.1017/ S0266467406003415

De Figueiredo EB, La Scala N Jr (2011) Greenhouse gas balance due to the conversion of sugarcane areas from burned to green harvest in Brazil. Agriculture. Ecosystems & Environment 141, 77-85. doi: 10.1016/j.agee 2011.02.014

Franzluebbers AJ (1999) Microbial activity in response to water-filled pore space of variably eroded southern Piedmont soils. Applied Soil Ecology 11, 91-101. doi: 10.1016/S0929-1393(98)00128-0

Gardini E, Antisari LV, Guerzoni ME, Sequi P (1991) A simple gas chromatographic approach to evaluate C[O.sub.2] release, [N.sub.2]O evolution, and [O.sub.2] uptake from soil. Biology and Fertility of Soils 12, 1-4. doi: 10.1007/BF00369380

Howard DM, Howard PJA (1993) Relationships between C[O.sub.2] evolution, moisture content and temperature for a range of soil types. Soil Biology & Biochemistry 25, 1537 1546. doi: 10.1016/0038-0717(93) 90008-Y

Keeling RF, Shertz SR (1992) Seasonal and interannual variations in atmospheric oxygen and implications for the global carbon cycle. Nature 358, 723-727. doi: 10.1038/358723a0

Knicker H. Gonzalez-Vila FJ, Gonzalez-Vazquez R (2013) Biodegradability of organic matter in fire-affected mineral soils of Southern Spain. Soil Biology & Biochemistry 56, 31-39. doi:10.1016/j.soilbio.2012.02.021

Kyaw Tha Paw U, Xu L, lderis AJ, Kochendorfer J, Wharton S, Rolston DE, Hsiao TC (2006) Simultaneous carbon dioxide and oxygen measurements to improve soil efflux estimates. Kearney Foundation of Soil Science: soil carbon and California's terrestrial ecosystems. (Final Report. 2004211, 1/1/2005-12/31/2006). Available at:<http://keamey.ucdavis.edu/OLD%20MISSION/2004_Final_Reports/2004211 PawU_FINALkms.pdf>. Accessed in 1 January 2017.

Lai R (2004) Soil carbon sequestration to mitigate climate change. Geoderma 123, 1-22. doi:10.1016/j.geoderma.2004.01.032

Lai R (2009) Challenges and opportunities in soil organic matter research. European Journal of Soil Science 60, 158-169. doi: 10.1111/j.13652389.2008.01114.x

Lai R, Kimble JM (1997) Conservation tillage for carbon sequestration. Nutrient Cycling in Agroecosystems 49. 243-253. doi:10.1023/A:10097 94514742

Linn DM, Doran JW (1984) Effect of water-filled pore space on carbon dioxide and nitrous oxide production in tilled and no-tilled soils. Soil Science Society of America Journal 48, 1267-1272. doi: 10.2136/sssaj 1984.03615995004800060013x

Luo Z, Hu C, Zhou J, Cen K (2006) Stability of mercury on three activated carbon sorbents. Fuel Processing Technology 87, 679-685. doi: 10.1016/ j.fuproc.2005.10.005

Marques TA, Sasso CG, Sato AM, Souza GM (2009) Queima do canavial: aspectos sobre a biomassa vegetal, fertilidade do solo e emissao de C[O.sub.2] para atmosfera. Bioscience Journal 25, 83-89.

Melillo JM, Steudler PA, Aber JD, Newkirk K, Lux H, Bowles FP, Catricala C, Magill A, Ahrens T, Morrisseau S (2002) Soil warming and carboncycle feedbacks to the climate system. Science 298, 2173-2176. doi: 10.1126/science.1074153

Oliveira MW, Trivelin PCO, Penatti CP, Piccolo MC (1999) Decomposifao e liberagao de nutrientes da palha de cana-deaf ucar em campo. Pesquisa Agropecuaria Brasileira 34, 2359-2362. doi: 10.1590/S0100-204X199 9001200024

Panosso AR, Marques Junior J, Pereira GT, La Scala Junior N (2009) Spatial and temporal variability of soil C[O.sub.2] emission in a sugarcane area under green and slash-and-burn managements. Soil & Tillage Research 105, 275-282. doi:10.1016/j.still.2009.09.008

Panosso AR, Marques J, Milori DMBP, Ferraudo AS, Barbieri DM, Pereira GT, La Scala N (2011) Soil C[O.sub.2] emission and its relation to soil properties in sugarcane areas under slash-and-burn and green harvest. Soil & Tillage Research 111, 190-196. doi: 10.1016/j.still.2010.10.002

Peel MC, Finlayson BL, McMahon TA (2007) Updated world map of the Koppen-Geiger climate classification. Hydrology and Earth System Sciences 11, 1633-1644. doi: 10.5194/hess-11-1633-2007

Pereira ES, Queiroz AC, Paulino MF, Cecon PR, Valadares Filho SC, Miranda LF, Fernandes AM, Cabral LC (2000) Determinacao das fracoes proteicas e de carboidratos e taxas de degradacao in vitro da cana-de-acucar, da cama de frango e do farelo de algodao. Revista Brasileira de Zootecnia 29, 1887-1893. doi: 10.1590/S1516-359820000 00600039

Ranjard L, Richaume A (2001) Quantitative and qualitative microscale distribution of bacteria in soil. Research in Microbiology 152, 707-716. doi: 10.1016/S0923-2508(01)01251-7

Silva MAS, Mafia AL, Albuquerque JA, Bayer C, Mielniczuk J (2005) Atributos fisicos do solo relacionados ao armazenamento de agua em um Argissolo Vermelho sob diferentes sistemas de preparo. Ciencia Rural 35, 544-552. doi:10.1590/S0103-84782005000300009

Smagin AV (2006) Soil phases: the gaseous phase. In 'Soils: basic concepts and future challenges'. 1st edn. (Eds G Certini, R Scalenghe) pp. 75-90. (Cambridge University Press: New York)

Smagin AV. Dolgikhb AV, Karelin DV (2016) Experimental studies and physically substantiated model of carbon dioxide emission from the exposed cultural layer of Velikii Novgorod. Eurasian Soil Science 49, 450-456. doi: 10.1134/S1064229316040116

Soil Survey Staff (2014) 'Keys to Soil Taxonomy.' 12th edn. (United States Department of Agriculture: United States of America)

Stern L, Baisden WT, Amundson R (1999) Processes controlling the oxygen isotope ratio of soil C[O.sub.2]: analytic and numerical modeling. Geochimica et Cosmochimica Acta 63, 799-814. doi: 10.1016/S00167037(98)00293-2

Stotzky G (1960) A simple method for the determination of the respiratory quotient of soils. Canadian Journal of Microbiology 6, 439-452. doi: 10.1139/m60-050

Tofoli GR, Velini ED, Negrisoli E, Cavenaghi AL, Martins D (2009) Dinamica do tebuthiuron em palha de cana-de-afucar. Planta Daninha 27, 815-821. doi: 10.1590/S0100-83582009000400020

Urquiaga BM, Oliveira OC, Lima E, Guimaraes DHV (1991) A Importancia de nao queimar a palha na cultura de cana-de-a9ucar. Available at: <www.embrapa.br/agrobiologia/busca-de-publicacoes/-/publicacao/623354/ a-importancia-de-nao-queimar-a-palha-na-cultura-de-cana-deacucai>. Accessed 10 January 2017.

Wei S, Zhang X, McLaughlin NB, Liang A, Jia S, Chen X, Chen X (2014) Effect of soil temperature and soil moisture on C[O.sub.2] flux from eroded landscape positions on black soil in Northeast China. Soil & Tillage Research 144, 119-125. doi: 10.1016/j.still.2014.07.012

Wick AF. Phillips RL, Liebig MA, West M, Daniels WL (2012) Linkages between soil micro-site properties and C[O.sub.2] and [N.sub.2]O emissions during a simulated thaw for a northern prairie Mollisol. Soil Biology & Biochemistry 50, 118-125. doi:10.1016/j.soilbio.2012.03.010

Wolinska A, Stepniewska Z, Sxafranek-Nakonieczna A (2011) Effect of selected physical parameters on respiration activities in common Polish mineral soils. Polish Journal of Environmental Studies 20, 1075-1082.

Xu M, Qi Y (2001) Soil-surface C[O.sub.2] efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California. Global Change Biology 7, 667-677. doi: 10.1046/j.1354-1013.2001. 00435.x

Risely Ferraz de Almeida (A,E), Daniel de Bortoli Teixeira (B), Rafael Montanari (C), Antonio Cesar Bolonhez (C), Edson Belisario Teixeira (C), Mara Regina Moitinho (A), Alan Rodrigo Panosso (A), Kurt A. Spokas (D), and Newton La Scala Junior (A)

(A) Sao Paulo State University (FCAV/UNESP), Jaboticabal, Sao Paulo, Brazil.

(B) University of Marilia (Unimar), Marflia, Sao Paulo, Brazil.

(C) Sao Paulo State University (FEIS/UNESP), llha Solteira, Sao Paulo, Brazil.

(D) ARS, USDA, Soil and Water Res Management Unit, St Paul, MN, 55108, USA.

(E) Corresponding author. Email: rizely@gmail.com

Received 7 December 2016, accepted 27 December 2017, published online 20 April 2018

Caption: Fig. 1. (a) Precipitation, (b) soil moisture, (e) [O.sub.2] uptake, (d) C[O.sub.2] emission and (e) apparent respiratory quotient (ARQ) of soil under contrasting sugarcane management regimes of mechanised harvesting with straw (GH) and burned straw (BH). Note: days marked with different lower-case letters differ according to t-test (P [less than or equal to] 0.05). The [O.sub.2] uptake and ARQ show no significant difference for days according to t-test (P [less than or equal to] 0.05).

Caption: Fig. 2. (a) Soil cumulative C[O.sub.2] emission and soil cumulative [O.sub.2] uptake and (b) apparent repiratory quotient (Total ARQ) of soil under contrasting sugarcane management regimes of mechanized harvesting with straw (GH) And burned straw (BH). Note: bars identified with different upper-case letters differ according to t-test (P [less than or equal to] 0.05).

Caption: Fig. 3. Relationship of soil moisture (%) with (a, c) [O.sub.2] uptake and (b, d) C[O.sub.2] emission, within a sugarcane area under contrasting sugarcane management regimes of mechanised harvesting with straw (GH) and burned straw (BH).

Caption: Fig. 4. Relationship between soil C[O.sub.2] emission and soil [O.sub.2] uptake within a sugarcane soil under contrasting sugarcane management regimes of mechanised harvesting (a) with burned straw (BH) and (b) straw (GH).
Table 1. Physical and chemical attributes of a Red-Yellow Latosol
under contrasting sugarcane management regimes involving mechanised
harvesting with the presence of straw (GH) and with straw burning
(BH) pH in 0.1 KC1, soil organic matter (SOM), phosphorus (P),
sulfar (S), calcium ([Ca.sup.2+]), potassium ([K.sup.+]), magnesium
([Mg.sup.2+]), aluminium ([Al.sup.3+]), cation exchange capacity
(CEC), macroporosity (Macro), microporosity (Micro), total porosity
(TP) and water-filled porosity (WFP)

                           Soil chemical attributes

Straw             PH               SOM                P
management

                  --         (g [dm.sup.-3])   (mg [dm.sup.-3])

BH           5.11 [+ or -]   16.30 [+ or -]      8.0 [+ or -]
                 0.04             0.58               0.26

GH           5.18 [+ or -]   15.90 [+ or -]      8.2 [+ or -]
                 0.08             0.23               0.29

                          Soil chemical attributes

Straw               S            [Ca.sup.2+]      [K.sup.+]
management

             (mg [dm.sup.-3])                   ([mmol.sub.c]
                                                [dm.sup.-3])

BH             5.5 [+ or -]     19.7 [+ or -]   1.36 [+ or -]
                   0.22              1.1            0.09

GH             5.3 [+ or -]     22.0 [+ or -]   1.26 [+ or -]
                   0.26             0.86            0.13

                    Soil chemical attributes

Straw        [Mg.sup.2+]    [Al.sup.3+]         CEC
management

              ([mmol.sub.c] [dm.sup.-3])

BH           9.1 [+ or -]   0 8 [+ or -]   55 06 [+ or -]
                 0.81           0.2             1.95

GH           8.7 [+ or -]   0.9 [+ or -]   53.46 [+ or -]
                 0.58           0.31            0.72

                        Soil physical attributes

Straw             Sand              Silt             Clay
management

                     (g [kg.sup.-1])

BH            613 [+ or -]     101.0 [+ or -]   286.0 [+ or -]
                   1.0              1.0              0.0

GH            602 [+ or -]     111.5 [+ or -]   286.0 [+ or -]
                  0.35              0.35             0.0

                Soil physical attributes

Straw            Macro           Micro
management

BH           14.6 [+ or -]   29.01 [+ or -]
                 2.01             0.60

GH           11.1 [+ or -]   31.58 [+ or -]
                 1.37             1.05

                Soil physical attributes

Straw             TP               WFP
management        (%)

BH           43.69 [+ or -]   18.73 [+ or -]
                 1.66              5.6

GH           42.75 [+ or -]   18.49 [+ or -]
                 1.07              6.4
COPYRIGHT 2018 CSIRO Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2018 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:de Almeida, Risely Ferraz; de Bortoli Teixeira, Daniel; Montanari, Rafael; Bolonhez, Antonio Cesar;
Publication:Soil Research
Article Type:Report
Geographic Code:3BRAZ
Date:Jul 1, 2018
Words:6545
Previous Article:Soil erosion analysis by RUSLE and sediment yield models using remote sensing and GIS in Kelantan state, Peninsular Malaysia.
Next Article:Quantification of wetting front movement under the influence of surface topography.
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |