• Authors:
    • Thomas,Amy R. C.
    • Bond,Alan J.
    • Hiscock,Kevin M.
  • Source: Global Change Biology Bioenergy
  • Volume: 5
  • Issue: 3
  • Year: 2013
  • Summary: Reduction in energy sector greenhouse gas GHG emissions is a key aim of European Commission plans to expand cultivation of bioenergy crops. Since agriculture makes up 1012% of anthropogenic GHG emissions, impacts of land-use change must be considered, which requires detailed understanding of specific changes to agroecosystems. The greenhouse gas (GHG) balance of perennials may differ significantly from the previous ecosystem. Net change in GHG emissions with land-use change for bioenergy may exceed avoided fossil fuel emissions, meaning that actual GHG mitigation benefits are variable. Carbon (C) and nitrogen (N) cycling are complex interlinked systems, and a change in land management may affect both differently at different sites, depending on other variables. Change in evapotranspiration with land-use change may also have significant environmental or water resource impacts at some locations. This article derives a multi-criteria based decision analysis approach to objectively identify the most appropriate assessment method of the environmental impacts of land-use change for perennial energy crops. Based on a literature review and conceptual model in support of this approach, the potential impacts of land-use change for perennial energy crops on GHG emissions and evapotranspiration were identified, as well as likely controlling variables. These findings were used to structure the decision problem and to outline model requirements. A process-based model representing the complete agroecosystem was identified as the best predictive tool, where adequate data are available. Nineteen models were assessed according to suitability criteria, to identify current model capability, based on the conceptual model, and explicit representation of processes at appropriate resolution. FASSET, ECOSSE, ANIMO, DNDC, DayCent, Expert-N, Ecosys, WNMM and CERES-NOE were identified as appropriate models, with factors such as crop, location and data availability dictating the final decision for a given project. A database to inform such decisions is included.
  • Authors:
    • Venkateswarlu, B.
    • Rao,V. U. M.
  • Source: Climate Change Modeling, Mitigation, and Adaptation
  • Year: 2013
  • Authors:
    • Mahmood, K.
    • Awan, A. R.
    • Singh, R. K.
    • Stille, L.
    • Akanda, R.
    • Smeets, E. M. W.
    • Wicke, B.
    • Faaij, A. P. C.
  • Source: Journal of Environmental Management
  • Volume: 127
  • Issue: September
  • Year: 2013
  • Summary: This study explores the greenhouse gas balance and the economic performance (i.e. net present value (NPV) and production costs) of agroforestry and forestry systems on salt-affected soils (biosaline (agro) forestry) based on three case studies in South Asia. The economic impact of trading carbon credits generated by biosaline (agro)forestry is also assessed as a potential additional source of income. The greenhouse gas balance shows carbon sequestration over the plantation lifetime of 24 Mg CO2-eq. ha(-1) in a rice-Eucalyptus camaldulensis agroforestry system on moderately saline soils in coastal Bangladesh (case study 1), 6 Mg CO2-eq. ha(-1) in the rice-wheat- Eucalyptus tereticornis agroforestry system on sodic/saline-sodic soils in Haryana state, India (case study 2), and 96 Mg CO2-eq. ha(-1) in the compact tree (Acacia nilotica) plantation on saline-sodic soils in Punjab province of Pakistan. The NPV at a discount rate of 10% is 1.1 k(sic) ha(-1) for case study 1, 4.8 k(sic) ha(-1) for case study 2, and 2.8 k(sic) ha(-1) for case study 3. Carbon sequestration translates into economic values that increase the NPV by 1-12% in case study 1, 0.1 -1% in case study 2, and 2-24% in case study 3 depending on the carbon credit price (1-15 (sic) Mg-1 CO2-eq.). The analysis of the three cases indicates that the economic performance strongly depends on the type and severity of salt-affectedness (which affect the type and setup of the agroforestry system, the tree species and the biomass yield), markets for wood products, possibility of trading carbon credits, and discount rate. (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • Cui, S.
    • Chang, X.
    • Xu, B.
    • Zhu, X.
    • Luo, C.
    • Wang, S.
    • Duan, J.
    • Zhang, Z.
  • Source: Plant and Soil
  • Volume: 362
  • Issue: 1-2
  • Year: 2013
  • Summary: Few studies have investigated the effect of nitrogen (N) fertilizer on ecosystem respiration (Re) under mixed legume and grass pastures sown at different seeding ratios,and data are almost entirely lacking for alpine meadow of the Tibetan Plateau. Our aim was to test the hypothesis that although a combination of legumes with grass and N fertilizer increases Re the combination decreases Re intensity (i.e. Re per unit of aboveground biomass) due to greater increases in aboveground biomass compared to increases in Re. This hypothesis was tested using different seeding ratios of common vetch (Vicia sativa L.) and oat (Avena sativa L.) with and without N fertilizer on the Tibetan plateau in 2009 and 2010. Re was measured using a static closed opaque chamber. Re intensity was estimated as the ratio of seasonal average Re during the growing season to aboveground biomass. Compared with common vetch monoculture pasture, mixed legume-grass pastures only significantly decreased Re intensity (with a decrease of about 75 %-87 %) in the drought year 2009 due to greater increases in aboveground biomass compared to increases in Re. There were no significant differences in Re and Re intensity among different seeding ratios of oat and common vetch in either year. N fertilizer significantly decreased Re intensity for common vetch monoculture pasture by 24.5 % in 2009 and 69.5 % in 2010 although it did not significantly affect plant production and Re. From the perspective of forage yield and Re, planting mixed legume-grass pastures without N fertilizer is a preferable way to balance the twin objectives of forage production and mitigation of atmospheric greenhouse gas emissions in alpine regions.
  • Authors:
    • Ruzibaev, E.
    • Akramkhanov, A.
    • Lamers, J. P. A.
    • McDonald, A.
    • Mirzabaev, A.
    • Ibragimov, N.
    • Kienzler, K. M.
    • Egamberdiev, O.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Rainfed and irrigated agricultural systems have supported livelihoods in the five Central Asian countries (CAC) for millennia, but concerns for sustainability and efficient use of land and water resources are long-standing. During the last 50 years, resource conserving technologies were introduced in large parts of the rainfed areas while the irrigated areas were expanded largely without considering resource conservation. In more recent years, the use of conservation agriculture (CA) practices has been reported for the different agricultural production (AP) zones in CAC, albeit centering on a single AP zone or on single factors such as crop yield, implements or selected soil properties. Moreover, conflicting information exists regarding whether the current practices that are referred to as 'CA' can indeed be defined as such. Overall information on an application of CA-based crop management in Central Asia is incomplete. This discussion paper evaluates experimental evidence on the performance of CA and other resource conserving technologies in the three main AP zones of CAC, provides an overview of farmer adoption of production practices related to CA, and outlines technical and non-technical challenges and opportunities for the future dissemination of CA practices in each zone. Agronomic (e.g. implements, crop yields, duration. and crop residues), institutional (e.g. land tenure) and economic (e.g. short vs. long-term profitability) perspectives are considered. At present, adoption of CA-based agronomic practices in the rainfed production zone is limited to partial crop residue retention on the soil surface or sporadically zero tillage for one crop out of the rotation, and hence the use of single CA components but not the full set of CA practices. In the irrigated AP zones, CA is not commonly practiced and many of the pre-conditions that typically encourage the rapid spread of CA practices appear to be absent or limiting. Further, our analysis suggests that given the diversity of institutional, socio-economic and agro-ecological contexts, a geographically differentiated approach to CA dissemination is required in the CAC. Immediate priorities should include a shift in research paradigms (e.g. towards more participatory approaches with farmers), development of commercially available reduced and no-till seeders suitable for smaller-scale farm enterprises, and advocacy so that decision makers understand how different policies may encourage or discourage innovations that lead towards more sustainable agricultural intensification in the CAC.
  • Authors:
    • Feizian, M.
    • Khalili, A.
    • Heidari, S.
    • Moradii, J.
    • Azizi, K.
  • Source: International Journal of AgriScience
  • Volume: 2
  • Issue: 4
  • Year: 2012
  • Summary: This experiment was undertaken to study the effect of different levels of gibberellic acid (GA 3) as a hormone on the yield components of soybean genotypes in summer double cropping as the second crop following a wheat harvest. The experiment was carried out in 4*2 factorial arrangement of a randomized complete block design (RCBD) with four replicates at the experimental farm of Lorestan Meteorological Office located in Khorramabad. 4 levels of GA 3 concentration (0.0 (as control), 125, 250, and 375 ppm) were sprayed over the plants and 2 levels of soybean genotypes (M 11 and L 17) were used for the experiment. The results showed that interactions between different levels of GA 3 and the soybean genotypes had significant effect on pod number per plant, seed number per pod, 1000-seed weight, and economic and biological yield ( p
  • Authors:
    • Khan, M.
    • Said, G.
    • Khan, M.
    • Khan, S.
    • Inayat, U.
    • Khalid, U.
  • Source: Journal of Integrative Agriculture
  • Volume: 11
  • Issue: 6
  • Year: 2012
  • Summary: Conservational tillage (CT) in combination with broad spectrum herbicide may be more efficient and economical in controlling weeds, reducing cost of cultivation, and enhancing wheat yield. Field experiments were carried out to evaluate the effect of tillage and herbicides on weeds and wheat yield under rice-wheat cropping system (RWCS). The results indicated that broad spectrum herbicides particularly, carfentrazone ethyl ester+isoproturon (Affinity 50 WDG) reduced weeds density by 93 and 95% compared to control and also produced the maximum grain yield (6818 and 6996 kg ha -1) and HI (harvest index, 44.7 and 44.6%) in 2007-2008 and 2008-2009 growing seasons, respectively. The maximum weeds infestation and the lowest yield were recorded in control. Tillage methods significantly influenced grain yield and HI, while no significant effect on all other parameters. The overall mean yield was significantly higher in zero tillage (5575 kg ha -1) and reduced tillage (5584 kg ha -1) compared to CT (5479 kg ha -1). Besides increasing wheat yield, Affinity 50 WDG and zero tillage are important weed management practices that can be integrated into wheat production in RWCS. However, in case of perennial weeds or insect pests' infestation, CT in combination with Affinity 50 WDG would be more productive than conservation tillage.
  • Authors:
    • Refaie, K.
    • Abou-Hussein, S.
    • Abdelraouf, R.
    • El-Metwally, I.
  • Source: Australian Journal of Basic and Applied Sciences
  • Volume: 6
  • Issue: 3
  • Year: 2012
  • Summary: Two field experiments were carried out during growing seasons 2010 and 2011; it was executed in Abo-Ghaleb farm, Cairo-Alex. Rood, 60 Km away from Cairo - Egypt, to study the effect of two irrigation systems (surface and subsurface drip irrigation and three water application rates (50, 75 and 100% from actual irrigation requirements) and three types for pulse irrigation (2 times per day, 3 times per day and 4 times per day and time-off between pulses was 30 minutes) with continuous drip irrigation (one time per day)). The following parameters were studied to evaluate the performance of pulse drip irrigation: (1) Clogging ratio of emitters "CRE", (2) Emission uniformity "EU" (3) Application efficiency "AE", (4) Irrigation water use efficiency of potato "IWUE potato" or water productivity. The results indicated that, CRE decreased by increasing the number of irrigation pulses at (100%, 75% and 50% from WRa) under surface and subsurface drip irrigation. This may be due to pulse technique (cycle on-off) created turbulence in the flow channel and this turbulence prevent particles suspended from accumulation in flow channel and outlets of emitters. The values of CRE under pulse surface drip irrigation were lower than values of CRE under pulse subsurface drip irrigation, this may be due to pulse technique makes vacuum in the network and this vacuum with subsurface drip system will pull more particles which around the emitters through inlets of emitters. From the data of EU, it increased by increasing the number of irrigation pulses (100%, 75% and 50% from WRa) under surface and subsurface drip irrigation. This was due to the positive effect of pulse drip irrigation on reducing CRE. (3) AE increased from 89% under continuous drip irrigation to maximum value where it become 94% after applying pulse technique with 4 pulses at 100% from water requirements under surface drip irrigation, recording an increase of 5.3%. (4) IWUE potato or water productivity increased by increasing number of irrigation pulses especially at (100% and 75% from WRa). IWUE potato increased from 1.44 (kg/m 3) under CDI to maximum value, where it become 2.36 (kg/m 3) after applying pulse technique with 4 pulses at 75% from WRa under SSDI, recording an increase 63.9%, this mean that can save 25% of water requirements per season which equal 2085.6 m 3 ha -1 from irrigation water.
  • Authors:
    • Abdou, A.
  • Source: American-Eurasian Journal of Agricultural & Environmental Sciences
  • Volume: 12
  • Issue: 1
  • Year: 2012
  • Summary: The study revealed the negative impact of international prices' fluctuation and increasing trends upon domestic plans to secure needs of price-subsidized bread in Egypt. Uncertainty with respect to international prices' changes call for neutralizing their influence on domestic prices. In this respect, the study suggested a contract agreement between the local authority and producers to deliver specific quotas of wheat and maize at prices determined in advance on bases of production costs and expected profitability of competitive crops, specifically clover, cotton and rice. The risk may still hold with respect to expected prices of competitive crops, rice in particular, as influenced by international price levels. However, such risk may be minimized if firmly activate regulations of irrigation water use, exerting limits upon rice's total acreage.
  • Authors:
    • Shivakoti, G.
    • Nawaz, R.
    • Perret, S.
    • Ahmad, S.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: This paper investigated the farm level diversity in operation and farm performances under two different governance situations in irrigation systems of Punjab Province of Pakistan: Farmer-Managed (FMIS) and Government-Managed Irrigation Scheme (GMIS). Questionnaire surveys and multivariate analyses were conducted. Farms typology was developed based on farm size. Results reveal a water-land-farming strategy nexus. Larger farms perform better in both schemes. Wheat cropping is a strategic choice, specialized, and exclusive, with low input, and low income. Conversely, maize and rice cropping tit well in diversification and intensification strategies, leading to higher farm income. Also poor financial basis and extension services for smaller farms do not support intensification and diversification. The paper shows that productivity of production factors, level of intensification, farm size are closely interlocked, in a general context of poor performances and institutional reforms. Groundwater access is also a key to success, since canal irrigation only cannot sustain an intensification-diversification process. The paper concludes that transfer of canal irrigation management to farmers will not solve all issues, and yet remains probably the only long-term solution. Areas for public intervention on, inter alia, land, finance, extension, markets remain necessary in FMIS and towards smaller farms.