• Authors:
    • Traerup,Sara
    • Stephan,Jean
  • Source: Climatic Change
  • Volume: 131
  • Issue: 3
  • Year: 2015
  • Summary: Increasing attention is being given to climate technologies on the international climate change agenda, not least in the agricultural sector and water sectors, and to technologies for adaptation. However investments in technology-based adaptation (seeds, dams, irrigation, etc.) are complicated by the fact that it remains difficult to predict future climate change impacts, especially on a local scale. In addition, evidence for the costs and benefits of implementing adaptation technologies is relatively limited. The analysis presented in this paper shows that there is a large potential for integrating adaptation technologies into the planning and implementation of on-going and future projects. Based on local-level data from a technology needs assessment project in Lebanon, this paper presents two examples of the economic feasibility of implementing adaptation technologies in the agricultural and water sectors. The results show that the technologies can be applied at low cost and with relatively little effort.
  • Authors:
    • Wilson,T. M.
    • McGowen,B.
    • Mullock,J.
    • Arnall,D. B.
    • Warren,J. G.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 5
  • Year: 2015
  • Summary: Fertilizer-induced N 2O-N emissions (the difference between fertilized and unfertilized soils) are estimated to be 0.01 kg N 2O-N kg -1 of applied N. One approach to limiting N 2O-N production in soils is by improving nitrogen use efficiency (NUE) in dryland agricultural systems. However, baseline data on the rate of emissions is needed to determine the potential impact that these efforts might have on N 2O-N concentrations in the atmosphere. A study was established in a long-term continuous winter wheat ( Triticum aestivum L.) fertility experiment in Stillwater, OK, to determine the effects of N rate on N 2O-N emissions from a dryland winter wheat-summer fallow system in the southern Great Plains of the United States to fill this knowledge gap. Cumulative emissions of N 2O-N varied from year to year and were influenced by environment and N rate. Emissions following N fertilizer application were typically highest following N application, as well as toward the end of the summer fallow period, when summer rainfall and temperatures were conducive for N 2O-N production chambers within plots historically receiving 134 kg N ha -1 annually went unfertilized for the 2012-2013 and 2013-2014 crop years and produced N 2O-N emissions equivalent to the 45 and 90 kg N ha -1 rate treatments. Annual cumulative emissions ranged from 0.009 to 0.024 kg N 2O-N kg -1 N applied with an average of 0.015 kg N 2O-N kg -1 N applied, illustrating the variability in N 2O-N emissions.
  • Authors:
    • Dang,Y. P.
    • Moody,P. W.
    • Bell,M. J.
    • Seymour,N. P.
    • Dalal,R. C.
    • Freebairn,D. M.
    • Walker,S. R.
  • Source: Soil & Tillage Research
  • Volume: 152
  • Year: 2015
  • Summary: In semi-arid sub-tropical areas, a number of studies concerning no-till (NT) farming systems have demonstrated advantages in economic, environmental and soil quality aspects over conventional tillage (CT). However, adoption of continuous NT has contributed to the build-up of herbicide resistant weed populations, increased incidence of soil- and stubble-borne diseases, and stratification of nutrients and organic carbon near the soil surface. Some farmers often resort to an occasional strategic tillage (ST) to manage these problems of NT systems. However, farmers who practice strict NT systems are concerned that even one-time tillage may undo positive soil condition benefits of NT farming systems. We reviewed the pros and cons of the use of occasional ST in NT farming systems. Impacts of occasional ST on agronomy, soil and environment are site-specific and depend on many interacting soil, climatic and management conditions. Most studies conducted in North America and Europe suggest that introducing occasional ST in continuous NT farming systems could improve productivity and profitability in the short term; however in the long-term, the impact is negligible or may be negative. The short term impacts immediately following occasional ST on soil and environment include reduced protective cover, soil loss by erosion, increased runoff, loss of C and water, and reduced microbial activity with little or no detrimental impact in the long-term. A potential negative effect immediately following ST would be reduced plant available water which may result in unreliability of crop sowing in variable seasons. The occurrence of rainfall between the ST and sowing or immediately after the sowing is necessary to replenish soil water lost from the seed zone. Timing of ST is likely to be critical and must be balanced with optimising soil water prior to seeding. The impact of occasional ST varies with the tillage implement used; for example, inversion tillage using mouldboard tillage results in greater impacts as compared to chisel or disc. Opportunities for future research on occasional ST with the most commonly used implements such as tine and/or disc in Australia's northern grains-growing region are presented in the context of agronomy, soil and the environment. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Dang,Y. P.
    • Seymour,N. P.
    • Walker,S. R.
    • Bell,M. J.
    • Freebairn,D. M.
  • Source: Soil & Tillage Research
  • Volume: 152
  • Year: 2015
  • Summary: Development of no-tillage (NT) farming has revolutionized agricultural systems by allowing growers to manage greater areas of land with reduced energy, labour and machinery inputs to control erosion, improve soil health and reduce greenhouse gas emission. However, NT farming systems have resulted in a build-up of herbicide-resistant weeds, an increased incidence of soil- and stubble-borne diseases and enrichment of nutrients and carbon near the soil surface. Consequently, there is an increased interest in the use of an occasional tillage (termed strategic tillage, ST) to address such emerging constraints in otherwise-NT farming systems. Decisions around ST uses will depend upon the specific issues present on the individual field or farm, and profitability and effectiveness of available options for management. This paper explores some of the issues with the implementation of ST in NT farming systems. The impact of contrasting soil properties, the timing of the tillage and the prevailing climate exert a strong influence on the success of ST. Decisions around timing of tillage are very complex and depend on the interactions between soil water content and the purpose for which the ST is intended. The soil needs to be at the right water content before executing any tillage, while the objective of the ST will influence the frequency and type of tillage implement used. The use of ST in long-term NT systems will depend on factors associated with system costs and profitability, soil health and environmental impacts. For many farmers maintaining farm profitability is a priority, so economic considerations are likely to be a primary factor dictating adoption. However, impacts on soil health and environment, especially the risk of erosion and the loss of soil carbon, will also influence a grower's choice to adopt ST, as will the impact on soil moisture reserves in rainfed cropping systems. (C) 2015 Elsevier B.V. All rights reserved.
  • Authors:
    • Fiore,A.
    • Dichio,B.
    • Celano,G.
    • Modarelli,A.
    • Palese,A. M.
    • Quinto,G.
    • Pergola,M. T.
    • Xiloyannis,C.
  • Source: Acta Horticulturae
  • Volume: 1084
  • Year: 2015
  • Summary: The most recent and recognised standards for carbon footprint (CFP) ISO 14067:2013 requires the inclusion of land based emissions (CO2 fluxes from soil organic carbon change and field emissions from fertilization) into greenhouse gas accounting. These two categories of emissions are often disregarded from CFP studies of fruit products. In the present paper a simple methodology to include land-based emissions into greenhouse gas (GHG) accounting of fruit product from perennial crops is tested on a case study, and the results compared to experimental measurement from literature in order to evaluate its point of strength and weakness; this methodology is based on IPCC guidelines for national GHG inventories (IPCC, 2006). All fossil (anthropogenic) and biogenic emissions arising from all agricultural operations during orchard life cycle have been accounted according ISO 14067:2013. Fertilization resulted to be the most impacting agricultural operation, together with the production of materials constituting the irrigation pipe system and its supporting structure (metal and cement poles, wire). The most innovative aspect of the tested methodology consists in considering the sink role of soil in fruit orchards managed according to sustainable agronomical practices (increasing of internal and external carbon input to soil). Comparison with measurements data from literature revealed that the simple methodology tested can be improved in order to improve the accuracy of the estimates according to pedoclimatic conditions and crop specificities. © 2015 ISHS.
  • Authors:
    • Lubbers,Ingrid M.
    • van Groenigen,Kees Jan
    • Brussaard,Lijbert
    • van Groenigen,Jan Willem
  • Source: Scientific Reports
  • Volume: 5
  • Year: 2015
  • Summary: Concerns about rising greenhouse gas (GHG) concentrations have spurred the promotion of no-tillage practices as a means to stimulate carbon storage and reduce CO2 emissions in agro-ecosystems. Recent research has ignited debate about the effect of earthworms on the GHG balance of soil. It is unclear how earthworms interact with soil management practices, making long-term predictions on their effect in agro-ecosystems problematic. Here we show, in a unique two-year experiment, that earthworm presence increases the combined cumulative emissions of CO2 and N2O from a simulated no-tillage (NT) system to the same level as a simulated conventional tillage (CT) system. We found no evidence for increased soil C storage in the presence of earthworms. Because NT agriculture stimulates earthworm presence, our results identify a possible biological pathway for the limited potential of no-tillage soils with respect to GHG mitigation.
  • Authors:
    • Mangalassery,S.
    • Sjoegersten,S.
    • Sparkes,D. L.
    • Mooney,S. J.
  • Source: The Journal of Agricultural Science
  • Volume: 153
  • Issue: 7
  • Year: 2015
  • Summary: The benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (77% over 10 years). In several cases yield reductions have been recorded e.g. c. 1-8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security?
  • Authors:
    • Plaza,E. H.
    • Navarrete,L.
    • Gonzalez-Andujar,J. L.
  • Source: Agriculture, Systems and Environment
  • Volume: 207
  • Year: 2015
  • Summary: Disturbances have a prominent role in structuring plant communities. However, in agroecosystems, the long-term effect of disturbances on determining trait distributions within weed communities remains little studied. We analyzed the effect of three tillage treatments, which differ in the intensity of soil disturbance, on the mean, the range and the distribution of four response traits within weed communities. We aim to test whether tillage acts as a filter restricting the range and the distribution of response traits within weed communities and leads to reduced response trait diversity or whether tilling may have a diversifying effect, creating opportunities for more phenotypes to coexist and increasing response trait diversity. To test this idea, we used data on weed abundance recorded over 24 years from an experiment in which conventional tillage (CT), minimum tillage (MT) and no-tillage (NT) systems were compared. We selected four response traits, maximum height, specific leaf area (SLA), seed weight and seed output, and computed the community weighted mean (CWM) of each trait, as well as four multi-trait metrics related to a different aspect of functional diversity. We found that soil disturbance increases available niche opportunities for weeds especially in terms of regenerative traits. CT, the greater soil disturbance, leads to a greater range and even distribution of the studied traits and that abundant weed species from CT plots hold more divergent trait values than those from MT and NT plots. Our results may be explained by the idiosyncrasy of our disturbance treatments that affect weed seed placement in the soil layers as well as the stratification and availability of soil nutrients. We also found that NT system selected for lower CWM of seed weight (and higher seed output) than MT and CT systems. NT places weed seeds mostly on the soil surface, where having a large seed output may be necessary to avoid the risk of decay or depredation. Conversely, MT and CT systems offer some advantage to other strategies such as larger seed sizes useful to germinate from depth. CWM of SLA was higher in NT and MT than in CT plots and this could be related to greater soil nutrient content in NT systems. In addition our results showed a general trend over experimental time for weed communities to increase in height (and slightly in SLA and seed production) while reducing in seed size. These features are generally associated with intensive farming systems.
  • Authors:
    • Sapkota,T. B.
    • Kaushik Majumdar
    • Jat,M. L.
  • Source: Better Crops with Plant Food
  • Volume: 99
  • Issue: 3
  • Year: 2015
  • Summary: In a collaborative effort between the International Maize and Wheat Improvement Centre and the International Plant Nutrition Institute to test, pilot and upscale Nutrient Expert (NE; a decision support system)-based fertilizer management, on-farm participatory research was conducted in 7 districts (Karnal, Kurukshetra, Kaithal, Ambala, Sonepat, Panipat, and Yamunanager) of Haryana (India) to evaluate and compare the NE-based strategies in conventional and no-till wheat production systems. For this, 15 on-farm experiments were established in 2010-11 and 2011-12. The four nutrient management treatments included: (1) NE-based recommendation; (2) NE+GreenSeeker (GS; handheld sensors): NE recommendation supplemented with GS-guided application of N; (3) SR: state fertilizer recommendation; and (4) FFP or the farmers fertilizer application practice. These treatments were compared for agronomic productivity, economic profitability and total greenhouse gas emissions. Total greenhouse gas emissions from wheat production were estimated using the Cool Farm Tool. The results showed that both grain yield and net return were higher with NE-based strategies compared to FFP and SR. The estimated total carbon footprint (i.e. GWP per tonne of wheat grain production and per US$ of net return) was also lower for NE-based strategies than other nutrient management strategies. Thus, the use of precision nutrient management tools such as NE and GS are important for increasing wheat yields and farmer profits yet minimizing the environmental footprint of wheat production.
  • Authors:
    • Guillaume,T.
    • Damris,M.
    • Kuzyakov,Y.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 9
  • Year: 2015
  • Summary: Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm, and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber, and extensive rubber plantations in Jambi Province on Sumatra Island. The focus was on two processes: (1) erosion and (2) decomposition of soil organic matter. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). On average, converting forest to plantations led to a loss of 10 Mg C ha -1 after about 15 years of conversion. The C content in the subsoil was similar under the forest and the plantations. We therefore assumed that a shift to higher delta 13C values in plantation subsoil corresponds to the losses from the upper soil layer by erosion. Erosion was estimated by comparing the delta 13C profiles in the soils under forest and under plantations. The estimated erosion was the strongest in oil palm (358 cm) and rubber (3310 cm) plantations. The 13C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. Nonetheless, based on the lack of C input from litter, we expect further losses of SOC in oil palm plantations, which are a less sustainable land use compared to rubber plantations. We conclude that delta 13C depth profiles may be a powerful tool to disentangle soil erosion and SOC mineralization after the conversion of natural ecosystems conversion to intensive plantations when soils show gradual increase of delta 13C values with depth.