• Authors:
    • Kannan, K.
    • Verma, H.
    • Mishra, A.
  • Source: Irrigation and Drainage
  • Volume: 61
  • Issue: 3
  • Year: 2012
  • Summary: A model was developed to modify the canal delivery schedule of a major irrigation project of eastern India for both monsoon and dry seasons that adopted the procedure of daily water balance/moisture balance simulation in the root zone depth. In addition to the prevailing continuous schedule, four alternative rotational schedules during the monsoon and five alternative rotational schedules during the dry season were considered for simulation. Daily water balance simulation was performed for 17 and 15 years for the monsoon season and the dry seasons, respectively. Simulation results for the monsoon revealed that a 15-day rotational schedule (15 days canal operation followed by 15 days canal closure) was the best alternative over the prevailing continuous schedule. To agree with the findings of the study model, field experiments were conducted during the monsoon season for three consecutive years. Highest rice grain yields of 4.92 t/ha ( Swarna) and 4.46 t/ha ( Surendra) were recorded in plots with 15-day rotational schedules. During the dry season, considering both paddy and other dry season crops grown together in the command, a 7-day canal operation followed by a 7-day canal closure rotational schedule was found to be the best alternative. Besides creating a favourable water regime and better crop evapo-transpiration (ET), this schedule saved about 10.3% of water over actual water supplies.
  • Authors:
    • Subramanian, S.
    • Meyhofer, R.
    • Nyasani, J.
    • Poehling, H.
  • Source: Entomologia Experimentalis et Applicata
  • Volume: 142
  • Issue: 3
  • Year: 2012
  • Summary: The study aimed at determining thrips species composition and thrips population density on French bean planted as a sole crop and as an intercrop with either sunflower, Irish potato, or baby corn, in various combinations. Field experiments were conducted in two seasons to examine: (1) thrips population development and thrips species composition over time, (2) effect of intercrops on thrips population density and natural enemies, and (3) effect of intercrops on French bean yield. The experiments were conducted at the Kenya Agricultural Research Institute, Embu, Kenya in a randomized complete block design with four replicates. The thrips population on French beans increased with time. It showed a peak at the flowering stage then started declining when the crops were nearing senescence. French beans hosted four thrips species, Megalurothrips sjostedti (Trybom), Frankliniella schultzei (Trybom), Frankliniella occidentalis (Pergande), and Hydatothrips aldolfifriderici (Karny) (all Thysanoptera: Thripidae) in order of decreasing abundance. The main thrips species on Irish potato and sunflower was F. schultzei. Baby corn hosted only Frankliniella williamsi (Hood) and Thrips pusillus (Bagnall). A monocrop of French bean hosted more thrips than a French bean intercrop mix. Thrips natural enemies such as Orius spp. and Ceranisus spp. were recorded in all crop plants but in especially high numbers on French bean and baby corn, respectively. Plots with French bean alone had about 1.4 times higher yields compared to intercropped plots of French bean with sunflower and French bean with baby corn. However, the percentage of pods that could get rejected on the market due to thrips damage was highest on plots with French bean alone (68 and 63%) and lowest on plots with French bean and baby corn (35 and 37%) in the first and second seasons, respectively. This study showed that a complex of thrips is found in the field and its composition varies with crop stage and species. Intercropping French bean with other crops compromises on French bean yield but reduces damage to the French bean pods, thereby enhancing marketable yield.
  • Authors:
    • Afolayan, S.
    • Olorunmaiye, P.
  • Source: Notulae Scientia Biologicae
  • Volume: 4
  • Issue: 1
  • Year: 2012
  • Summary: A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT) Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9 WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34%) in all the plots except in citrus/maize plot (0.78%) at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m -2 respectively) than in citrus/groundnut plot (143.00 m -2). Similarly, significantly lower grass weed densities were produced in citrus/ Mucuna and citrus/sweet potato (0.33 m -2 each) plots than the control plot (11.33 m -2). Whereas citrus/ Corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m -2) than citrus/ Mucuna plot (126.47 g m -2) at 3 WAP, citrus/large green plot (16.15 g m -2) and citrus/groundnut plot (123.25 g m -2) followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m -2 in all the plots compared with control plot.
  • Authors:
    • Cole, D.
    • Orozco, F.
  • Source: Ecohealth research in practice: innovative applications of an ecosystem approach to health
  • Year: 2012
  • Summary: This chapter describes an agricultural project (Ecosalud II) in Ecuador that aims to tackle the complex drivers of inappropriate use of highly hazardous pesticides, with the long-term goal of greater agroecosystem sustainability, including better human health. The project is similar to Ecosalud I, apart from some modifications, including an expansion of the project to 3 provinces (Carchi, Chimborazo and Tungurahua,). Furthermore, in Ecosalud II, "potato platforms" were used as social spaces that encouraged diverse actors with different knowledge, experience and decision-making power to gather monthly to address issues related to potato farming. The participants included small-scale farmers, leaders of community organizations, technical staff of nongovernmental development organizations (NGOs), staff of various municipal governments, provincial government representatives and provincial university faculty members. Drivers that affected the livelihoods and health of farm families are as follows: cheap and readily available highly hazardous pesticides; farmers' lack of knowledge about handling pesticides and reducing their exposure in the field and at home; poor general awareness of the extent of health impacts among both NGO and government actors; and weak policy responses to promote alternative crop-management technologies and practices that favour the sustainability of agro-ecosystem and farmers' health. These issues are tackled based on knowledge production, capacity building and multi-stakeholder collaboration. Data show that the strategic communication and use of research results with farmers, key government officials, NGOs and other stakeholders was effective in fostering change in potato-production systems in the three provinces targeted by the project and helped make potato production a safer income-generating activity with less damage to farmers' health and their environment.
  • Authors:
    • Inubushi, K.
    • Kawahigashi, M.
    • Funakawa, S.
    • Ivanov, I.
    • Manakhov, D.
    • Zdanovich, G.
    • Manakhova, E.
    • Prikhodko, V.
    • Okitsu, S.
    • Matsushima, M.
    • Sugihara, S.
    • Nagano, H.
  • Source: Soil Science & Plant Nutrition
  • Volume: 58
  • Issue: 2
  • Year: 2012
  • Summary: The effects of different land-use histories on contents of soil carbon (C) and nitrogen (N) and fluxes of greenhouse gases [carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)] measured using the closed chamber method were investigated in the Arkaim museum reserve located in the South Ural of Russia. A natural forest site (NF) and two grassland sites that had different land-use histories (CL: cropland until 1991; PST: pasture until 1991; both sites have been fallow for 18 years) were selected for soil sampling and gas flux measurements. The vegetation in NF was mainly Betula pendula Roth. with steppe cherry and grassy cover. Perennial grasses (Stipa spp., Festuca spp. and others) have been planted in CL and PST since 1991 to establish reserve mode, and the projective cover of these plants were > 90% in both sites in 2009. Soil samples were taken from the A horizon in the three sites, and additionally samples of the O horizon were taken from NF. The contents of soil C and N [total C, total N, soluble organic C, soluble N and microbial biomass C (MBC)] in the O horizon of NF were the largest among all investigated soils (p 0.05). Our current research indicated that, in soils of the Eurasian steppe zone of Russia, total C, total N and MBC were affected not only by current land-use (i.e., fallow grassland vs. natural forest) but also by past (until 18 years ago) land-use.
  • Authors:
    • Healey, J.
    • Attarzadeh, N.
    • Soto, G.
    • Haggar, J.
    • Edwards-Jones, G.
    • Noponen, M.
  • Source: Agriculture Ecosystems & Environment
  • Volume: 151
  • Year: 2012
  • Summary: Coffee plays a key role in sustaining millions of livelihoods around the world. Understanding GHG emissions from coffee supply chains is important in evaluating options for climate change mitigation within the sector. We use data from two long-term coffee agroforestry experiments in Costa Rica and Nicaragua to calculate carbon footprints (CF) for coffee and identify emission hotspots within different management systems, levels of inputs and shade types. Management system and input level were the main cause of variation in CFs. Carbon footprints for 1 kg of fresh coffee cherries were between 0.26 and 0.67 kgCO(2)e for conventional and 0.12 and 0.52 kgCO(2)e for organic management systems. The main contributor to GHG emissions for all management systems was the inputs of organic and inorganic nitrogen. Nitrous oxide emissions from pruning inputs contributed between 7% and 42% of CFs. However, these estimates were strongly influenced by the choice of emission factor used in the calculations. Research is required to develop emission factors that account for different qualities and management of nitrogen inputs to enable effective calculation of the CF from different management strategies, and especially from the pruning and organic inputs managed in agroforestry systems. As such, effective climate change mitigation strategies can only be developed from site-specific studies which utilise accurate accounting and regional-specific emission factors. (c) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Madari, B. E.
    • Petter, F. A.
  • Source: Revista Brasileira de Engenharia Agrícola e Ambiental
  • Volume: 16
  • Issue: 7
  • Year: 2012
  • Summary: Due to the high activity of microorganisms, the loss of soil organic matter is high in tropical regions. This loss becomes even greater if the soil is managed improperly or when there is no technology that leverages the permanence of the soil carbon by maintaining appropriate levels of organic matter, providing chemical, physical and biological soil improvements and contributing to reduce CO2 emissions to the atmosphere. Due to its aromatic structure, biochar is a highly stable form of carbon in the soil that may contribute to the reduction of greenhouse gas emissions, such as CO2, N2O and CH4, and act as a soil conditioner, improving the physical and chemical properties of the soil. Biochar may also result in increased productivity due to the improvement of soil attributes or a possible electrophysiological effect. Research over the past decades has demonstrated the potential of biochar as a soil conditioner, improving fertility and nutrient-use efficiency, in addition to maximising the productivity of crops, such as soybean and rice.
  • Authors:
    • Rasmussen, L.
    • Bruun, T.
    • Rasmussen, K.
  • Source: Energy Policy
  • Volume: 51
  • Year: 2012
  • Summary: The need to mitigate climate change makes production of liquid biofuels a high priority. Substituting fossil fuels by biodiesel produced from Jatropha curcas has gained widespread attention as Jatropha cultivation is claimed to offer green house gas emission reductions. Farmers respond worldwide to this increasing demand by converting forests into Jatropha, but whether Jatropha-based biodiesel offers carbon savings depends on the carbon emissions that occur when land use is changed to Jatropha. This paper provides an impact assessment of a small-scale Jatropha project in Cabo Delgado, Mozambique. The paper outlines the estimated impacts on above and below-ground carbon stocks when land use is changed to increase Jatropha production. The results show that expansion of Jatropha production will most likely lead to the conversion of miombo forest areas to Jatropha, which implies a reduction in above and below-ground carbon stocks. The carbon debts created by the land use change can be repaid by replacing fossil fuels with Jatropha-based biodiesel. A repayment time of almost two centuries is found with optimistic estimates of the carbon debt, while the use of pessimistic values results in a repayment time that approaches the millennium. (C) 2012 Elsevier Ltd. All rights reserved.
  • Authors:
    • Das, S. N.
    • Venkanna, R.
    • Nikhil, G. N.
    • Swamy, Y. V.
    • Chaudhury, G. Roy
  • Source: Atmósfera
  • Volume: 25
  • Issue: 1
  • Year: 2012
  • Summary: Methane (CH4) and nitrous oxide(N2O)emission estimates were made for Vigna mango and Vigna radiata legumes. The affecting soil parameters like redox potential, soil temperature were studied to evaluate CH4 and N2O emissions. The CH4 was negative and N2O was positive for Vigna mungo, almost throughout the cropping period. The redox potential was more than +100 mV during the entire cropping period with a maximum N2O flux of 11.67 mu g m(-2) h(-1). The raise in soil temperature and the redox potential during harvest further increased the N2O flux to 18.38 mu g m(-2) h(-1). The seasonally integrated flux E((SIF)) for CH4 and N2O for Vigna mungo was calculated to be -4.06 g.m(-2) and 3.38 mg m(-2) respectively. Similarly E((SIF))values estimated for Vigna radiata cropping season were 0.009 g m(-2) and -7.6 mg m-2, whereas for the post harvesting period the fluxes were 0.02 g m(-2) and 4.06 mg m(-2) for CH4 and N2O respectively. The soil parameters like organic carbon and nutrients such as ammonia, nitrate and nitrite during the cropping season were evaluated. The emission of greenhouse gases (GHG) was also correlated to various physicochemical parameters of soil.
  • Authors:
    • Okeyo, J.
    • Vanlauwe, B.
    • Kimetu, J. M.
    • Waswa, B.
    • Bationo, A.
    • Kihara, J.
    • Mukalama, J.
    • Martius, C.
  • Source: Experimental Agriculture
  • Volume: 48
  • Issue: 2
  • Year: 2012
  • Summary: Reduced tillage is said to be one of the potential ways to reverse land degradation and ultimately increase the productivity of degrading soils of Africa. We hypothesised that crop yield following a modest application of 2 t ha(-1) of crop residue in a reduced tillage system is similar to the yield obtained from a conventional tillage system, and that incorporation of legumes in a cropping system leads to greater economic benefits as opposed to a cropping system involving continuous maize. Three cropping systems (continuous maize monocropping, legume/maize intercropping and rotation) under different tillage and residue management systems were tested in sub-humid western Kenya over 10 seasons. While soybean performed equally well in both tillage systems throughout, maize yield was lower in reduced than conventional tillage during the first five seasons but no significant differences were observed after season 6. Likewise, with crop residue application, yields in conventional and reduced tillage systems are comparable after season 6. Nitrogen and phosphorus increased yield by up to 100% compared with control. Gross margins were not significantly different among the cropping systems being only 6 to 39% more in the legume-cereal systems relative to similar treatments in continuous cereal monocropping system. After 10 seasons of reduced tillage production, the economic benefits for our cropping systems are still not attractive for a switch from the conventional to reduced tillage.