- Authors:
- Sakalauskas, A.
- Avizienyte, D.
- Romaneckas, K.
- Masilionyte, L.
- Buragiene, S.
- Sarauskis, E.
- Source: Energy
- Volume: 69
- Issue: SI
- Year: 2014
- Summary: To achieve energy independence, Lithuania and other Baltic countries are searching for new ways to produce energy. Maize is a crop that is suitable for both food and forage, as well as for the production of bioenergy. The objective of this work was to assess the energy efficiency of maize cultivation technologies in different systems of reduced tillage. The experimental research and energy assessment was carried out for five different tillage systems: DP (deep ploughing), SP (), DC (deep cultivation), SC (shallow cultivation) and NT (no tillage). The assessment of the fuel inputs for these systems revealed that the greatest amount of diesel fuel (67.2 l ha -1) was used in the traditional DP system. The reduced tillage systems required 12-58% less fuel. Lower fuel consumption reduces the costs of technological operations and reduces CO 2 emissions, which are associated with the greenhouse effect. The agricultural machinery used in reduced tillage technologies emits 107-223 kg ha -1 of CO 2 gas into the environment, whereas DP emits 253 kg ha -1 of CO 2. The energy analysis conducted in this study showed that the greatest total energy input (approximately 18.1 GJ ha -1) was associated with the conventional deep-ploughing tillage technology. The energy inputs associated with the reduced-tillage technologies, namely SP, DC and SC, ranged from 17.1 to 17.6 GJ ha -1. The lowest energy input (16.2 GJ ha -1) was associated with the NT technology. Energy efficiency ratios for the various technologies were calculated as a function of the yield of maize grain and biomass. The best energy balance and the highest energy efficiency ratio (14.0) in maize cultivation was achieved with the NT technology. The energy efficiency ratios for DP, SP, DC and SC were 12.4, 13.4, 11.3 and 12.0, respectively.
- Authors:
- Korth, K.
- Chen, P.
- Gbur, E. E.
- Brye, K. R.
- Smith, F.
- Source: Soil Science
- Volume: 179
- Issue: 3
- Year: 2014
- Summary: One of the most significant contributors to the greenhouse effect is carbon dioxide (CO2) gas in the atmosphere. Soil respiration, the combined production of CO2 from soil, as a result of root and microorganism respiration, is the largest flux of CO2 from the terrestrial ecosystem to the atmosphere. Considering land use can greatly impact soil C storage and cycling, agricultural management practices can also greatly affect soil respiration and CO2 emissions. Therefore, the effects of long-term residue management (i.e., residue burning and nonburning, and conventional [CT] and no-tillage [NT]) and residue level (i.e., high and low) on soil respiration during the soybean [Glycine max (L.) Merr.] growing season were examined over 2 consecutive years (i.e., 2011 and 2012) in a wheat (Triticum aestivum L.)-soybean, double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta region of eastern Arkansas after more than 9 years of consistent management. Soil respiration rates from individual plots ranged from 0.53 to 40.7 and from 0.17 to 13.1 mol CO2.m(-2).s(-1) throughout the 2011 and 2012 soybean growing seasons, respectively, and differed (P < 0.05) among treatment combinations on two and five of nine and 11 measurement dates in 2011 and 2012, respectively. Regardless of residue level, soil respiration was generally greater (P < 0.05) from CT than NT. Estimated season-long CO2 emissions were 10.2% less (18.5 Mg CO2 ha(-1)) from residue burning than from non-burning (20.6 Mg CO2.ha(-1); P = 0.032). Averaged over years and all other field treatments, estimated season-long CO2 emissions were 15.5% greater from CT (21.0 Mg CO2 ha(-1)) than from NT (18.1Mg CO2 ha(-1); P = 0.020). Understanding long-term management effects on soil C losses, such as soil respiration, from common and widespread agricultural systems, such as the wheat-soybean, double-crop system, in eastern Arkansas can help improve policies for soil and environmental sustainability throughout the lower Mississippi River Delta region.
- Authors:
- Source: Soil Science
- Volume: 179
- Issue: 3
- Year: 2014
- Summary: High variability in soil and climatic conditions results in limited changes in soil aggregate-associated carbon (C) and nitrogen (N) levels as affected by management practices during a crop-growing season in the field. We evaluated the effects of crop species (spring wheat [Triticum aestivum L.], pea [Pisum sativum L.], and fallow), N fertilization rate (0.11 and 0.96 g N pot(-1)), and residue placement (no residue, surface placement, and incorporation into the soil) and rate (0, 20, and 40 g pot(-1)) on soil aggregation and C and N contents during a growing season under controlled soil and climatic conditions in the greenhouse. Soil samples collected from the field were grown with crops in the greenhouse and analyzed for aggregation and soil organic C, total N, particulate organic C, and particulate organic N contents in aggregates. Residue C and N losses, proportion of macroaggregates (> 0.25 mm), and soil C and N contents in microaggregates (< 0.25 mm) were higher in surface residue placement (20 g pot(-1)) under pea with 0.11 g N pot(-1) than the other treatments. The soil organic C and soil total N were greater in surface residue placement (40 g pot(-1)) under wheat with 0.96 g N pot(-1) in large and intermediate macroaggregates (8.00-4.75 and 4.75-2.00 mm, respectively), particulate organic N was greater in surface residue placement (20 g pot(-1)) under pea with 0.11 g N pot in large macroaggregates, but particulate organic C was greater in residue incorporation (20 g pot(-1)) under fallow with 0.96 g N pot(-1) in intermediate macroaggregate than the other treatments. Under controlled soil and environmental conditions, soil C and N levels in aggregates changed rapidly during a crop-growing season. Surface residue placement increased soil aggregation and C and N storage with concurrent losses of residue C and N, but residue incorporation increased coarse organic matter fraction. Results from this short-term experiment in the greenhouse agree with those obtained from the long-term study in the field.
- Authors:
- Cocco, S.
- Dixon, L.
- Trumbore, S. E.
- Bol, R.
- Agnelli, A.
- Corti, G.
- Source: Agriculture Ecosystems and Enviroment
- Volume: 193
- Year: 2014
- Summary: To examine the effects of vineyard soil management on soil C and N content and quality, we studied harrowed and grass-covered vineyards on a soil developed on plio-pleistocene, marine sediments. A soil naturally covered by grasses adjacent to the vineyards served as control. To reach this goal, we assessed (1) the distribution of C and N and their 13C and 15N signatures in different soil organic matter pools, (2) the amount of C and N as live and dead vine fine roots and their 13C, 15N and 14C signatures, and (3) the stocks of C and N forms accumulated at two soil-depth intervals (0-50 and 50-100 cm). Independent of the soil management, the vines increased the total organic C and total N content in the deeper soil horizons because of root turnover and rhizodeposition processes. In the upper horizons, a greater organic matter accumulation was fostered by the presence of the grass cover and the absence of tillage. The grass cover favoured the organic C storage mainly in the form of particulate and highly stabilised organic matter (humic acids and humin), and reduced the soil N content by plant uptake, whereas the harrowing produced a greater abundance of fulvic acids, which were mainly ascribed to oxidative processes enhanced by the soil tillage. In both vineyard soils, decaying vine roots represented an important source of organic C and N, especially in the deepest horizons. Indeed, isotope analyses revealed a more intense degradation of the dead vine roots in the deeper soil portion, where they likely constituted the main substrate for soil microorganisms. In the deepest horizons of the grass-covered vineyard, the greater mean residence time of the decaying vine roots and the lower root production were attributed to the easily available energetic substrates supplied by grass root turnover and rhizodeposition, which were preferentially used by microorganisms. This fact fostered a larger C accumulation in the grass-covered than in the harrowed vineyard.
- Authors:
- Bandyopadhyay, K. K.
- Lal, R.
- Source: Geoderma
- Volume: 232/234
- Year: 2014
- Summary: Soils can be a source or sink for the atmospheric greenhouse gases (GHGs) depending on the land use management, which needs to be understood properly for devising management strategies to mitigate climate change. It is hypothesized that the aggregate size distribution under different land use management practices and the C and N concentration in these aggregates may influence GHG (CO 2, N 2O and CH 4) emissions from soil. To test this hypothesis, a laboratory incubation study was conducted using soils from a 16-year old tillage experiment on corn ( Zea mays L.) and the adjoining forest on a Crosby silt loam soil (Haplic Luvisols) at the Waterman Agricultural and Natural Resource Laboratory of the Ohio State University (OSU), Columbus, Ohio. It was observed that in forest soil, cumulative CO 2 and N 2O emissions were significantly higher than those from the cultivated soil by 81.2 and 100%, respectively. However, there was no significant difference between conventional tillage (CT) and no till (NT) with respect to the cumulative CO 2 and N 2O emissions. Emissions were significantly higher from the large macro-aggregates than from other aggregate size fractions. There was net CH 4 uptake by the soil during the incubation period. The cumulative CO 2 and N 2O emissions and CH 4 uptake from different aggregate size fractions accounted for 59, 56, and 47% of the emissions/uptake of these gases from the bulk soil, respectively. The contributions of the large macro-aggregates towards the bulk soil CO 2 (39%) and N 2O (37.9%) emissions and CH 4 uptake (49.7%) were significantly higher than those of the micro-aggregates and mineral fraction. Total soil carbon, nitrogen, particulate carbon and nitrogen, and mineral associated carbon and nitrogen accounted for 87, 87 and 66% variation in the cumulative CO 2 and N 2O emissions and CH 4 uptake, respectively.
- Authors:
- Verhallen, A.
- Hayes, A.
- Congreves, K. A.
- Eerd, L. L. van
- Hooker, D. C.
- Source: Canadian Journal of Soil Science
- Volume: 94
- Issue: 3
- Year: 2014
- Summary: Long-term studies allow for quantification of the effects of crop production practices, such as tillage and crop rotation, on soil quality and soil C and N stores. In two experiments at Ridgetown, ON, we evaluated the long-term (11 and 15 yr) effect of tillage system and crop rotation on soil quality via the Cornell Soil Health Assessment (CSHA) at 0-15 cm and soil organic C (SOC) and total N at 5-, 10-, and 20-cm increments to 120 cm depth. The CSHA soil quality score and SOC and total N were higher with no-till (NT) than fall moldboard plough with spring cultivation (conventional tillage, CT) and rotations with winter wheat [soybean-winter wheat (S-W) and soybean-winter wheat-corn (S-W-C)] compared with rotations without winter wheat. In both long-term trials, NT had ca. 21 Mg ha -1 more or 14% higher SOC than CT in the 0- to 100-cm soil profile, a trend which contrasts previous research in eastern Canada. Thus, the two long-term trial results at Ridgetown suggest that to improve soil quality and storage of C and N, growers on clay loam soil in southwestern Ontario should consider adopting NT production practices and including winter wheat in the rotation.
- Authors:
- Olsen, D.
- Harner, L.
- Merrill, S.
- Tanaka, D.
- Sanderson, M.
- Nichols, K.
- Hendrickson, J.
- Archer, D.
- Liebig, M.
- Source: JOURNAL OF SOIL AND WATER CONSERVATION
- Volume: 69
- Issue: 4
- Year: 2014
- Authors:
- Lugato,E.
- Montanarella, L.
- Jones, A.
- Bampa, F.
- Panagos, P.
- Source: Global Change Biology
- Volume: 20
- Issue: 1
- Year: 2014
- Summary: Proposed European policy in the agricultural sector will place higher emphasis on soil organic carbon (SOC), both as an indicator of soil quality and as a means to offset CO 2 emissions through soil carbon (C) sequestration. Despite detailed national SOC data sets in several European Union (EU) Member States, a consistent C stock estimation at EU scale remains problematic. Data are often not directly comparable, different methods have been used to obtain values (e.g. sampling, laboratory analysis) and access may be restricted. Therefore, any evolution of EU policies on C accounting and sequestration may be constrained by a lack of an accurate SOC estimation and the availability of tools to carry out scenario analysis, especially for agricultural soils. In this context, a comprehensive model platform was established at a pan-European scale (EU+Serbia, Bosnia and Herzegovina, Croatia, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) using the agro-ecosystem SOC model CENTURY. Almost 164 000 combinations of soil-climate-land use were computed, including the main arable crops, orchards and pasture. The model was implemented with the main management practices (e.g. irrigation, mineral and organic fertilization, tillage) derived from official statistics. The model results were tested against inventories from the European Environment and Observation Network (EIONET) and approximately 20 000 soil samples from the 2009 LUCAS survey, a monitoring project aiming at producing the first coherent, comprehensive and harmonized top-soil data set of the EU based on harmonized sampling and analytical methods. The CENTURY model estimation of the current 0-30 cm SOC stock of agricultural soils was 17.63 Gt; the model uncertainty estimation was below 36% in half of the NUTS2 regions considered. The model predicted an overall increase of this pool according to different climate-emission scenarios up to 2100, with C loss in the south and east of the area (involving 30% of the whole simulated agricultural land) compensated by a gain in central and northern regions. Generally, higher soil respiration was offset by higher C input as a consequence of increased CO 2 atmospheric concentration and favourable crop growing conditions, especially in northern Europe. Considering the importance of SOC in future EU policies, this platform of simulation appears to be a very promising tool to orient future policymaking decisions.
- Authors:
- Flower, K.
- Riethmuller, G.
- Manalil, S.
- Source: Soil & Tillage Research
- Volume: 143
- Year: 2014
- Summary: Field trials were conducted to study the emission of nitrous oxide during the summers of 2012 and 2013 from fields with harvested field pea, harvested wheat and winter fallow at Merredin and Cunderdin respectively, two wheat growing regions of Western Australia. The nitrous oxide emission fluxes from these treatments were regularly monitored during the postharvest summer period using a closed chamber technique, before and after wetting the soil. Very low nitrous oxide flux occurred in the dry soil conditions prior to wetting. However, significantly increased nitrous oxide flux was observed at both the sites after wetting, with emissions from a harvested field pea plots being 55-86 fold higher than prior to wetting at the two sites. After wetting, the field pea plots also had significantly higher emissions (3.47-3.87 g N2O-N ha(-1) h(-1)) than those following winter fallow (1.17-1.95 g N2O-N ha(-1) h(-1)), although no nitrogen fertiliser was applied to either during the crop growing period. The harvested wheat plots had emissions that were similar (1.18-3.15 g N2O-N ha(-1) h(-1)) or higher than the winter fallow treatment. The sudden increase in nitrous oxide was observed 3 h after wetting, with a significant reduction in nitrous oxide flux occurring approximately 20 h after wetting. This indicates the need for regular monitoring of nitrous oxide flux to capture the emission pulses that occur under favourable conditions. Nitrous oxide flux was positively correlated with soil nitrate-N, water filled pore space and soil temperature at both the sites. The study shows that the use of winter fallow does not result in high soil nitrous oxide emissions over the following summer, compared with harvested wheat or field peas. The studies are important because more frequent summer rains are predicted in the region, and as shown in this study, high summer temperature together with rainfall could lead to nitrous oxide emission peaks. (C) 2014 Elsevier B.V. All rights reserved.
- Authors:
- Porqueddu, C.
- Pulina, P.
- Nieddu, G.
- Mercenaro, L.
- Source: Agriculture Ecosystems and Environment
- Volume: 192
- Year: 2014
- Summary: In the Mediterranean area, the use of cover crops in vineyards is still debated and the results of the few scientific experiments considering the influence of cover crop on grapevine are often conflicting. This work aims at providing useful indications on sustainable management for irrigated vineyards growing in a hot and dry region. A five year study was carried out in NW Sardinia, Italy, in a 8 year old vineyard cv. Carignano. To evaluate interactions between grapevine and cover crop as well as the economic impact of intercropping, soil tillage (T1) was compared with 4 inter-row treatments: natural covering (T2), complex commercial grass-legume mixture (T3), simple experimental grass-legume mixture (T4) and perennial grass Dactilys glomerata cv Currie (T5). During the five years of the experiment, the mixtures have ensured a higher level of soil covering compared to the other treatments. Moreover, the covering and the contribution to the dry matter yield for every component of the mixtures changed drastically with an increased presence of D. glomerata. Compared to the soil tillage, the cover crops reduce the vigor but does not affect yield. Regarding fruit quality, only the perennial grass influenced positively the amount of total anthocyanins. The cost analysis has not evidenced strong differences among treatments or limiting factors for growers related to the use of cover crop in vineyards.