• Authors:
    • Bosco,S.
    • Volpi,I.
    • o Di Nasso,N. N.
    • Triana,F.
    • Roncucci,N.
    • Tozzini,C.
    • Villani,R.
    • Laville,P.
    • Neri,S.
    • Mattei,F.
    • Virgili,G.
    • Nuvoli,S.
    • Fabbrini,L.
    • Bonari,E.
  • Source: Italian Journal of Agronomy
  • Volume: 10
  • Issue: 3
  • Year: 2015
  • Summary: Agricultural activities are co-responsible for the emission of the most important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Development of methodologies to improve monitoring techniques for N2O are still needful. The LIFE+IPNOA project aims to improve the emissions monitoring of nitrous oxide from agricultural soils and to identify the agricultural practices that can limit N2O production. In order to achieve this objective, both a mobile and a stationary instrument were developed and validated. Several experimental field trials were set up in two different sites investigating the most representative crops of Tuscany (Central Italy), namely durum wheat, maize, sunflower, tomato and faba bean. The field trials were realized in order to test the effect on N2O emissions of key factors: tillage intensity, nitrogen fertiliser rate and irrigation. The field trial on durum wheat was set up in 2013 to test the effect of tillage intensity (minimum and conventional tillage) and nitrogen fertilisation rate (0, 110, 170 kg N ha-1) on soil N2O flux. Monitoring was carried out using the IPNOA mobile prototype. Preliminary results on N2O emissions for the durum wheat growing season showed that mean daily N2O fluxes ranged from –0.13 to 6.43 mg m-2 day-1 and cumulative N2O-N emissions over the period ranged from 827 to 2340 g N2O-N ha-1. Tillage did not affect N2O flux while increasing nitrogen fertilisation rate resulted to significantly increase N2O emissions. The IPNOA mobile prototype performed well during this first year of monitoring, allowing to catch both very low fluxes and peaks on N2O emissions after nitrogen supply, showing a good suitability to the field conditions. © S. Bosco et al., 2015 Licensee PAGEPress, Italy.
  • Authors:
    • Fontana,M.
    • Berner,A.
    • Mäder,P.
    • Lamy,F.
    • Boivin,P.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: soil conservation practices are growingly used with different aims such as reducing fuel consumption and preserving soil organic carbon (soc). among others, reduced tillage (rt) often replaces conventional tillage (ct). However, the compared impact of these practices on soil quality remains a matter of controversy. Moreover, the various changes expected are rarely considered all together though they are known to interact. this study aimed at characterizing together the changes in soc, microbial activity, and a large set of physical properties when comparing rt and ct performed on a clayey soil. shrinkage analysis allowed to characterize simultaneously the soil pore systems, their volume, air and water content, the hydro-structural stability, and the swelling properties of the soil. analysis of covariance (ancoVa) was used to compare the soil properties taking in account clay content variability. we showed that clay and soc changes induced most of the variance of the other parameters. at standardized clay content soc was increased with rt in the topsoil and homogenized with smaller values in the ct layer. Many soil physical and biochemical properties were enhanced accordingly with rt which induced a more stable soil with increased porosity and improved microbial activity. sharp changes in soil quality seem to occur at the ct plow limit, while smooth changes with depth are observed with rt. independently from the soc increase with rt, changes in physical properties and microbial activity could be due to mechanical stress in ct or changes in organic matter quality in rt. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Goglio,Pietro
    • Smith,Ward N.
    • Grant,Brian B.
    • Desjardins,Raymond L.
    • McConkey,Brian G.
    • Campbell,Con A.
    • Nemecek,Thomas
  • Source: Journal of Cleaner Production
  • Volume: 104
  • Year: 2015
  • Summary: Soil carbon sequestration, a climate change mitigation option for agriculture, can either increase or decrease as a result of land management change (LMC) and land use change (LUC). To estimate all greenhouse gas (GHG) exchanges associated with various agricultural systems, life cycle assessments (LCAs) are frequently undertaken. To date LCA practitioners have not had a well-defined procedure to account for soil C in their assessments and as a consequence it is often not included. In this study, various methods used to estimate soil C changes due to (i) LMC and (ii) LUC are examined to assess soil C accounting methodologies in the life cycle inventory (LCI) of agricultural LCAs. A compromise between accuracy and completeness in LCA methods is necessary. A ranking of the preference of soil C accounting methods is suggested based on user expertise and data quality. For large scale assessment, the timing of soil CO2 emissions should be taken into account. If indirect LUC is relevant, a sensitivity analysis of assessment methods should be conducted because the methods highly affect assessment results. A common soil C accounting method that can be easily applied in agricultural LCA needs to be established and an agreement on indirect LUC methods will facilitate the assessment of LMC and LUC within agricultural LCAs. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.
  • Authors:
    • Queiros,J.
    • Malca,J.
    • Freire,F.
  • Source: Journal of Cleaner Production
  • Volume: 99
  • Year: 2015
  • Summary: This article presents a life-cycle assessment (LCA) of rapeseed produced in Central Europe (France, Germany and Poland), addressing different fertilization and management practices. Two alternative fertilization scenarios were compared (on the basis of the most common fertilizer types used in Europe, namely nitrogen, phosphate P 2O 5, and potash K 2O fertilizers) and two different scenarios of soil management practices were assessed (taking into account climate and soil type prevalent in each region). Six environmental impact categories were investigated: abiotic depletion; global warming; acidification; eutrophication; ozone layer depletion; and photochemical oxidation. Results showed that the choice of fertilizer type had significant implications in the environmental impacts. Calcium ammonium nitrate (CAN) manufacturing had considerably higher greenhouse gas emissions than urea production, due to the use of nitric acid in the former. In terms of field emissions, ammonia and nitrate released following the application of nitrogen fertilizers dominated the acidification and eutrophication impacts. Nitrogen-phosphorus-potassium (NPK) compounds showed particularly high impacts in terms of photochemical oxidation, as a result of sulfur dioxide emissions from manufacturing. The remaining fertilizers (P 2O 5 and K 2O) hardly contributed to the impacts. Soil carbon change associated with different agricultural management practices significantly contributed to the greenhouse gas (GHG) intensity of rapeseed production, but important soil carbon stock variations were calculated: between 938 (release) and 271 kg CO 2eq/1000 kg dry seeds (sequestration) due to different standard soil organic carbon contents in the three rapeseed production systems and alternative tillage methods in the reference scenarios of land management.
  • Authors:
    • Visser,F.
    • Dargusch,P.
    • Smith,C.
    • Grace,P. R.
  • Source: Journal of Cleaner Production
  • Volume: 103
  • Year: 2015
  • Summary: The various initiatives in the market place to quantify the sustainability levels of products are putting pressure on farmers to demonstrate a reduction in the environmental impacts of their crop management practices, and in particular with the lowering of the carbon footprints of their crops. At present there is no internationally accredited common method or carbon footprint model which generates site specific and LCA aligned emission estimates. The application of the Crop Carbon Progress Calculator (CCAP) is demonstrated for an irrigated cotton 'farm to ship' case study in Australia where we determine that the progress made in the 2011 crop against a 2002 crop base year amounts to 44% reduction in GHG emission levels. We estimate that for this particular case study the total carbon footprint of producing a bale of cotton up to ship's side or point of export is 323 kg CO 2e. This includes 182 kg CO 2e from the farm production phase, 73.1 kg CO 2e from the gin to port supply chain, and 68.1 kg CO 2e that results from emission from the stock piled gin trash at the gins. It appears that a feasible option to avoid these trash emissions is to incorporate the waste at farm level. Our analysis shows that this could generate an emissions credit of 48.8 kg CO 2e per bale at farm level, which will amount to a 27% reduction in the farm emissions footprint and a 15% reduction in the whole farm to ship carbon footprint. Due to a number of site specific environmental and crop management factors, there can be significant variances in crop carbon footprint outcomes.
  • Authors:
    • Yao ChunXue
    • Joseph,S.
    • Li LianQing
    • Pan GenXing
    • Lin Yun
    • Munroe,P.
    • Pace,B.
    • Taherymoosavi,S.
    • Zwieten,L. van
    • Thomas,T.
    • Nielsen,S.
    • Ye Jun
    • Donne,S.
  • Source: Pedosphere
  • Volume: 25
  • Issue: 5
  • Year: 2015
  • Summary: Utilization of biochar at high application rates can increase soil C and crop yields, decrease greenhouse gas emissions and reduce nutrient run-off from soils. However, the high application rate of 10 t ha -1 may not return a profit to the farmer due to the high cost of biochar. In this study biochar was modified through pre-treating the biomass and post-treating with phosphoric acid, minerals and different chemical fertilisers to study the effects of two new enhanced biochar fertilisers on the yield and quality of green pepper in a field experiment with 5 fertilisation treatments and 3 replications. The two new biochar fertilisers significantly ( P<<0.05) increased the yield of green pepper (11.33-11.47 t ha -1), compared with the conventional chemical fertiliser (9.72 t ha -1). The biochar fertiliser treatments improved the vitamin C content of green pepper from 236.99 to 278.28 mg kg -1, and also significantly ( P<0.05) reduced the nitrate content from 132.32 to 101.92 mg kg -1, compared with chemical fertiliser. This study indicated that, compared to the use of conventional chemical fertiliser, all of the biochar fertiliser treatments could significantly improve the yield and quality of green pepper.
  • Authors:
    • Aengelo Rodrigues,M.
    • Dimande,Paulo
    • Pereira,Ermelinda L.
    • Ferreira,Isabel Q.
    • Freitas,Sara
    • Correia,Carlos M.
    • Moutinho-Pereira,Jose
    • Arrobas,Margarida
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 103
  • Issue: 2
  • Year: 2015
  • Summary: Cover cropping is a major challenge in the sustainable management of rainfed olive orchards. From a 5 year study (2009-2014), the effect of a mixture of early-maturing and self-reseeding annual legumes (Legs) grown as a cover crop in a rainfed olive orchard was compared with a cover of natural vegetation fertilized with 60 kg nitrogen (N) ha(-1) year(-1) (NV +N), and a cover of natural vegetation not fertilized (NV -N). The study took place in NE Portugal. The following were assessed: (1) the performance of the covers by measuring ground cover percentages, dry matter yields and N content in aboveground biomass; (2) the soil fertility through chemical and microbiological assays and by growing plants in pot experiments; and (3) the nutritional status of olive trees and olive yields. Legumes gave higher ground-cover percentages, produced more biomass and accumulated more N in shoots in comparison to natural vegetation, whether fertilized or not. The results showed intense biological activity [microbial carbon (C) and N, CO2-C evolved in a laboratory incubation, metabolic quotient, total culturable fungi and bacteria, and acid phosphatase activity] in the 0-10 cm soil layer of the treatments producing more biomass (Legs and NV +N). However, soil available N was greater in soil samples from the Legs plot. N recoveries by turnip (Brassica rapa var. rapa L.) and rye (Secale cereale L.) grown in pot experiments were 84.4 and 60.2 mg pot(-1) in soil samples from the Legs treatment and 29.4 and 27.1 mg pot(-1) and 14.2 and 13.6 mg pot(-1), respectively in NV +N and NV -N plots. Sown legumes appeared less effective in increasing organic C than natural vegetation. Nevertheless, in the Legs plot the increase of easily mineralizable C was proportionally higher than the increase of total organic C, which may mean that a more reactive pool of organic C is created, which may reduce the turnover of organic C and N in the soil. In the 10-20 cm soil layer, total organic C was significantly lower in Legs (14.0 g kg(-1)) than in NV -N (22.1 g kg(-1)) and N +NV (25.2 g kg(-1)) treatments, likely due to a priming effect caused by mineral N coming from the surface layer. Two years after the trial started, the N nutritional status of the olive trees was significantly higher in Legs than in natural vegetation plots even when 60 kg N ha(-1) year(-1) was applied. The cumulative olive yields in NV -N and NV +N plots were only 58.6 and 77.7 % in comparison to those found in the Legs plot, if only the last four harvests were considered, which were those influenced by the ground-cover treatments (2010-2013).
  • Authors:
    • Crittenden,S. J.
    • Poot,N.
    • Heinen,M.
    • van Balen,D. J. M.
    • Pulleman,M. M.
  • Source: Soil and Tillage Research
  • Volume: 154
  • Year: 2015
  • Summary: Reduced tillage can improve soil physical quality relative to mouldboard ploughing by lessening soil disturbance, leaving organic matter at the soil surface, and stimulating soil biological activity. In organic farming, continuous ploughing may negate benefits to soil structure and function from increased use of manures and more diverse crop rotations, which are particularly important components of organic farming. The current study examined soil physical quality (i.e., properties and functioning) of a 4-year old reduced tillage system under organic and conventional farming with crop rotations that included root crops. Reduced tillage was compared to conventional mouldboard ploughing (MP) in 2 organic fields at different points of the same crop rotation (Org A and Org B) and 1 conventional field (Conv A). Reduced tillage consisted of non-inversion tillage (NIT) to 18-23. cm depth whereas MP was characterised by annual mouldboard ploughing to 23-25. cm depth. NIT improved soil water retention in Org B but had no effect in Org A. NIT increased soil aggregate stability at 10-20. cm depth compared to MP in all fields, and additionally at 0-10. cm in Conv A. Penetration resistance was higher in NIT in all fields. Furthermore, soil organic matter content was higher in NIT than MP at 0-10. cm depth in all fields and at 10-20. cm in Org B and Conv A. NIT increased carbon stocks in Org B but not in Org A. NIT statistically increased crop yields in spring wheat/faba bean mixture in Org A, and there was no yield penalty from NIT in Org B spring wheat nor Conv A sugar beet. In contrast, field-saturated hydraulic conductivity in all fields in autumn was lower in NIT. Differences in crop (i.e., phase of rotation) and associated organic inputs between Org A and B likely accounted for the differences in effects of tillage system. Overall, the NIT system improved or imposed no penalty on soil physical quality (except field-saturated hydraulic conductivity) and improved or imposed no penalty on crop yields and could therefore be considered as a viable alternative for farmers. © 2015 Elsevier B.V..
  • Authors:
    • Stuedemann, J.
    • Franzluebbers, A.
  • Source: Journal of Soil and Water Conservation
  • Volume: 70
  • Issue: 6
  • Year: 2015
  • Summary: Cover crops are a key component of conservation cropping systems. They can also be a key component of integrated crop-livestock systems by offering high-quality forage during short periods between cash crops. The impact of cattle grazing on biologically active soil carbon (C) and nitrogen (N) fractions has not received much attention. We investigated the impacts of tillage (conventional disk and no tillage) and cover crop management (ungrazed and grazed) on biologically active soil C and N fractions from biennial sampling during seven years of continuous management. Soil microbial biomass C was unaffected by cover crop management under conventional tillage, but was enhanced with grazing compared with no grazing under no tillage at a depth of 0 to 6 cm (0 to 2.4 in), as well as at 0 to 30 cm (0 to 12 in). The same effect occurred for the flush of carbon dioxide (CO2) following rewetting of dried soil during 3 days of incubation at a depth of 0 to 6 cm only, while it occurred for cumulative C mineralization during 24 days of incubation at a depth of 0 to 30 cm only. Grazing effects on net N mineralization during 24 days of incubation and residual soil inorganic N were nonexistent. All biologically active fractions of soil C and N were highly stratified with depth under no tillage and less so under conventional tillage. Cumulative stocks of soil C and N fractions to a depth of 0 to 30 cm were generally not significantly different between cover crop management systems, nor between tillage systems, except for (1) lower soil microbial biomass C with than without grazing under conventional tillage, (2) greater soil microbial biomass C with than without grazing under no tillage, and (3) lower cumulative C mineralization during 24 days under no tillage than under conventional tillage. Grazing of cover crops can be recommended as a strategy to promote greater adoption of cover cropping throughout the southeastern United States.
  • Authors:
    • Rochette, P.
    • Morel, C.
    • Lalande, R.
    • Gagnon, B.
    • Angers, D. A.
    • Ziadi, N.
    • Chantigny, M. H.
  • Source: Canadian Journal of Soil Science
  • Volume: 94
  • Issue: 3
  • Year: 2014
  • Summary: Adoption of conservation practices can induce beneficial changes to soil properties and related crop yields in which magnitude varies according to soil and climatic conditions but usually increases with time. A long-term field experiment was initiated in 1992 at L'Acadie in southern Quebec on a clay loam soil to evaluate the effect of tillage [mouldboard plow (MP) vs. conservation (CT)], synthetic N fertilization (0, 80, and 160 kg N ha -1) and synthetic P fertilization (0, 17.5, and 35 kg P ha -1) on soil functioning and grain yields of a corn-soybean rotation. Soil tillage was performed every year while synthetic fertilizers were applied only to the corn. Results obtained 12 to 20 yr after initiation of the study indicated that CT enhanced organic C accumulation, NO 3-N, P and K availability, microbial biomass and activity, and microbial community structure in the upper soil layer, likely due to leaving crop residues at the soil surface. The MP practice resulted in greater organic C content deeper, near the bottom of the plow layer, which promoted soil microbial activity at that depth. However, soil N 2O emissions were not affected by tillage. The N and P fertilization increased the availability of these nutrients, but had no significant effect on the soil microbial biomass, activity, and structure. Linear relationships were established between soil available P and cumulative P budgets obtained under MP or 0 kg P ha -1 under CT. Crop yields varied by year in this study but on average, MP yielded 10% more corn and 13% more soybeans than CT. Corn yield increased linearly with added synthetic N each year, whereas soybean yield was little affected by residual N, and both crops did not respond to fertilizer P. Response to N fertilization did not differ due to tillage or P. Despite higher costs associated with plowing, the profitability of MP was greater than CT on this clay loam soil due to greater yields. Specialized management practices (e.g., delayed planting, better herbicide selection, fall cover crop, in-row tillage) might help to improve CT performance on these cool, humid fine-textured soils.