• Authors:
    • Ortega, J. F.
    • Montoya, F.
    • Camargo, D. C.
    • Corcoles, J. I.
  • Source: Web Of Knowledge
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Potato ( Solanum tuberosum L.) yield is sensitive to water stress in the semiarid regions of Spain. This study was conducted to determine the effect of four irrigation treatments on potato tuber yield under one-quarter (4.9 ha) of the total irrigation area (18.4 ha) of a center pivot system in Albacete, Spain, during 2011 and 2012. Four irrigation treatments were applied, representing 60, 80, 100, and 120% of potato crop water requirement (CWR). In 2011, crop yield differed between the 60% irrigation treatment and the other treatments, whereas in 2012, yield differed between irrigation treatments with high (100 and 120%) and low (60 and 80%) water supply. Water use efficiency (WUE) ranged from 8.6 to 11.6 kg m -3 in 2011 and 7.1 to 8.4 kg m -3 in 2012, with significant differences among treatments in 2011. Differences in harvest index (HI) were observed between the irrigation seasons due to weather conditions of the second year. The 80% treatment was more efficient or equally efficient compared with the unstressed treatments and therefore represents a viable option when there are limited water supplies or high water costs.
  • Authors:
    • Lupwayi, N.
    • Blackshaw, R.
    • Li, L
    • Pearson, D.
    • Larney, F.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 6
  • Year: 2015
  • Summary: Dry bean ( Phaseolus vulgaris L.) production on the Canadian prairies has traditionally used wide rows, inter-row cultivation, and undercutting at harvest. Recent breeding efforts have produced cultivars with more upright growth which are better suited to solid-seeded narrow-row production systems. A 12 yr (2000-2011) study compared conservation (CONS) and conventional (CONV) management for dry bean in 3- to 6-yr rotations. The CONS rotations included reduced tillage, cover crops, feedlot manure compost, and solid-seeded narrow-row dry bean. Effects of CONS management on plant density were inconsistent with some years showing lower density when seeded into high-residue conditions. On average, there was a 3 d maturity advantage with CONS (103 d) vs. CONV (106 d) management. The CONS rotations showed significantly higher mean incidence (19%) of white mold [ Sclerotinia sclerotiorum (Lib.) de Bary] than CONV rotations (6%). Averaging across 12 yr, there was no significant rotation effect on yield ( P=0.19) showing that CONS production performed as good as CONV production. In the last 2 yr (2010-2011) of the study, in an attempt to reduce harvest losses, CONS dry bean was undercut rather than direct combined. This led to significantly higher (25%) yield with CONS (3311 kg ha -1) vs. CONV management (2651 kg ha -1). Our results provide incentive for more rapid adoption of conservation-oriented soil and crop management practices for dry bean production on the Canadian prairies, including narrow rows, reduced tillage, cover crops, and feedlot manure compost addition.
  • Authors:
    • Stinner, P.
  • Source: Energy, Sustainability and Society
  • Volume: 5
  • Issue: 4
  • Year: 2015
  • Summary: Background: Energy crops are of considerable importance for biogas production, especially in Germany. The main energy crops for that purpose are corn silage, grass silage, whole crop grain silage and other non-legume crops. The reason for preferring these crops is their high yield, which not only results in high yields of biogas per hectare but also in a high mitigation of greenhouse gases in the course of replacing fossil energy. This article aims to show an additional effect exerted on energy yield and mitigation of greenhouse gases by the use of legume energy crops. The symbiotic nitrogen fixation (SNF) of legumes compensates inorganic N fertilizer in conventional farms, if the digestate is applied as a fertilizer to the non-legume cash crops. The production of chemical N fertilizer is very energy intensive and leads to emissions of greenhouse gases from fossil energy consumption and from nitrous oxide generation. So, the creation of an effective organic fertilizer with nitrogen from biological N 2 fixation is a further energy add-on effect to the reduction of greenhouse gas emissions. Methods: For this article, data with regard to the SNF of legumes obtained in field experiments at the research station at Gladbacherhof (University of Giessen) from 2002 to 2005 were re-calculated and compared with data concerning energy need and greenhouse gas emissions in the process of producing mineral nitrogen fertilizer. In addition to the possible methane yield of these substrates, the saving in energy and greenhouse gas emissions by substituting mineral fertilizers is shown. Results: As a result, the possible replacement of primary energy by SNF of clover grass leys is calculated to be approximately less than 6.4 MWh ha -1 a -1. This is a yield that is reached in addition to the methane production, i.e. a possible reduction of greenhouse gas emissions through SNF per hectare of clover grass leys of more than 2 t CO 2 equivalents ha -1 a -1 can be achieved. Conclusions: Based on these results, it can be recommended to evaluate energy crops in a more holistic way. For legumes, the effect of SNF needs to be included into the energy and greenhouse balance.
  • Authors:
    • Pikula, D.
    • Faber, A.
    • Syp, A.
  • Source: Plant Soil Environ.
  • Volume: 61
  • Issue: 10
  • Year: 2015
  • Summary: The study presents the impact of management practices on greenhouse gas emissions (GHG) and nitrogen (N) losses calculated with a denitrification-decomposition model. Two cropping systems were analysed. The first rotation (A) consisted of potato, winter wheat, spring barley and corn. The second (B) included potato, winter wheat, spring barley and clover with grasses mixture. In A1 and B1 scenarios, fluxes were estimated on the basis of mineral fertilizers input, whereas in A2 and B2 scenarios the assessment of emissions was made with regards to manure. The results indicated that the application of manure in A rotation led to the increase of nitrous oxide (N 2O) emission, N leaching, N surplus, crop yields, and the decrease of nitrogen use efficiency higher than in B rotation. Additional doses of manure in A2 scenario increased the potential of the accumulation of soil organic carbon (SOC) and global warming potential (GWP) by 157%. In B2 scenario, SOC augmented more than three-fold but GWP increased only by 10%. The N losses and GHG emissions could be minimised by controlling N application through the implementation of nutrient management plan in which N doses are defined based on the crop needs and soil quality.
  • Authors:
    • Siebert, S.
    • Wolf, J.
    • Hoffmann, H.
    • Webber, H.
    • Gang, Z.
    • Ewert, F.
  • Source: Primary Research Article
  • Volume: 21
  • Issue: 11
  • Year: 2015
  • Summary: This study evaluates the impacts of projected climate change on irrigation requirements and yields of six crops (winter wheat, winter barley, rapeseed, grain maize, potato, and sugar beet) in Europe. Furthermore, the uncertainty deriving from consideration of irrigation, CO 2 effects on crop growth and transpiration, and different climate change scenarios in climate change impact assessments is quantified. Net irrigation requirement (NIR) and yields of the six crops were simulated for a baseline (1982-2006) and three SRES scenarios (B1, B2 and A1 B, 2040-2064) under rainfed and irrigated conditions, using a process-based crop model, SIMPLACE . We found that projected climate change decreased NIR of the three winter crops in northern Europe (up to 81 mm), but increased NIR of all the six crops in the Mediterranean regions (up to 182 mm yr -1). Climate change increased yields of the three winter crops and sugar beet in middle and northern regions (up to 36%), but decreased their yields in Mediterranean countries (up to 81%). Consideration of CO 2 effects can alter the direction of change in NIR for irrigated crops in the south and of yields for C3 crops in central and northern Europe. Constraining the model to rainfed conditions for spring crops led to a negative bias in simulating climate change impacts on yields (up to 44%), which was proportional to the irrigation ratio of the simulation unit. Impacts on NIR and yields were generally consistent across the three SRES scenarios for the majority of regions in Europe. We conclude that due to the magnitude of irrigation and CO 2 effects, they should both be considered in the simulation of climate change impacts on crop production and water availability, particularly for crops and regions with a high proportion of irrigated crop area.
  • Authors:
    • Peridy, N.
    • Zouabi, O.
  • Source: Article
  • Volume: 133
  • Issue: 2
  • Year: 2015
  • Summary: North African countries (NACs) are particularly concerned with climate change because of their geographical position (close to deserts) and their economic dependence on agriculture. We aim to provide additional insight into the impact of climate on agriculture for NACs, through the example of Tunisia. We first use disaggregated data, both at the geographical level (for 24 regions in Tunisia) and at the product level (cereals, olives, citrus fruit, tomatoes, potatoes and palm trees). Second, through spatial panel data analysis, we explore both the time and spatial dimensions of the data. This makes it possible to consider spatial interactions in agricultural production and the role of climate in these spatial spillover effects. Finally, the model not only includes direct climate variables, such as temperature and precipitation, but also indirect climate-related variables such as the stock of water in dams and groundwater. Results show that Tunisian agriculture is strongly dependent on the direct effects of temperature and precipitation for all the products considered at the regional level. The presence of dams and groundwater generally has a positive effect on agricultural production for irrigated crops with interesting spillover effects with neighboring regions. However, this impact is still considerably lessened in the case of detrimental climate conditions (indirect effect). These results raise the question of the sustainability of the growth in agricultural production in Tunisia in the case of significant climate change.
  • Authors:
    • Keisar, O.
    • Dar, Z.
    • Rubin, B.
    • Kazukro, H.
    • Hayut, E.
    • Fine, P.
    • Kashti, Y.
    • Goldwasser, Y.
    • Egozi, R.
    • Eshel, G.
    • Disegni, D.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 211
  • Year: 2015
  • Summary: We evaluated the impact of incorporating cover crops (CC) in commercial potato production, primarily to alleviate the severe soil erosion recorded in Mediterranean climate agriculture. As part of a 3-year study on this subject, we have developed complete agronomic management practices that enable sowing, growing and harvesting potatoes in soil covered with CC. This management scheme includes adjustment of specific management practices and farming machinery. In this paper, we explore the impact of including CC in potato production on runoff and soil erosion, weed suppression, and potato yield and quality. These are evaluated at the environmental, agronomic and economic levels. Our results clearly show that potato production under CC generates no yield reduction or nutrient deficiencies, reduces soil erosion by 95% and reduces runoff by more than 60%. Incorporation of CC in potato-growing practices also results in suppression of weeds (both species and biomass). The direct benefit to the grower from CC adoption is estimated at a 1.3% savings in variable costs of production. The benefit for the grower, along with additional environmental benefits translated to economic public goods calls for public intervention to support the transition from the conventional practices to CC practiced is essential.
  • Authors:
    • Hermansen, J. E.
    • Chirinda, N.
    • Olesen, J. E.
    • Meyer-Aurich, A.
    • Knudsen, M. T.
  • Source: Journal of Cleaner Production
  • Volume: 64
  • Issue: February
  • Year: 2014
  • Summary: Many current organic arable agriculture systems are challenged by a dependency on imported livestock manure from conventional agriculture. At the same time organic agriculture aims at being climate friendly. A life cycle assessment is used in this paper to compare the carbon footprints of different organic arable crop rotations with different sources of N supply. Data from long-term field experiments at three different locations in Denmark were used to analyse three different organic cropping systems ('Slurry', 'Biogas' and 'Mulching'), one conventional cropping system ('Conventional') and a "No input" system as reference systems. The 'Slurry' and 'Conventional' rotations received slurry and mineral fertilizer, respectively, whereas the 'No input' was unfertilized. The 'Mulching' and 'Biogas' rotations had one year of grass-clover instead of a faba bean crop. The grass-clover biomass was incorporated in the soil in the 'Mulching' rotation and removed and used for biogas production in the 'Biogas' rotation (and residues from biogas production were simulated to be returned to the field). A method was suggested for allocating effects of fertility building crops in life cycle assessments. The results showed significantly lower carbon footprint of the crops from the 'Biogas' rotation (assuming that biogas replaces fossil gas) whereas the remaining crop rotations had comparable carbon footprints per kg cash crop. The study showed considerable contributions caused by the green manure crop (grass-clover) and highlights the importance of analysing the whole crop rotation and including soil carbon changes when estimating carbon footprints of organic crops especially where green manure crops are included. (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • Andren, O.
    • Zhao, X.
    • Luo, Y.
  • Source: Acta Agriculturae Scandinavica Section B-Soil and Plant Science
  • Volume: 64
  • Issue: 3
  • Year: 2014
  • Summary: Soil organic carbon (SOC) is a major source/sink in atmospheric carbon balances. Farmland usually has a high potential for carbon dioxide (CO2) uptake from the atmosphere, but also for emission. Data from different areas are valuable for global SOC calculations and model development, and a survey of 108 agricultural fields in Lanzhou, China was performed. The fields were grouped by: cropping intensity (3 levels), cropping methodology (3), and crop species (10). Intensive cropping (two or more crops per year, typically vegetables), moderate (annuals in monoculture: wheat, maize, potato, melons), and extensive (orchards, lily [Lilium brownii] fields, fallow) were the intensity classes; and open field, greenhouse field, and sand-covered field (10-20 cm added on top of the topsoil) were the three methodologies. SOC concentration, pH, electrical conductivity, and soil bulk density were measured, and SOC mass (gm(-2) 0-20 cm depth) was calculated. SOC concentration was high in cauliflower, wheat, leaf vegetables, and fruit vegetables; moderate in potato, fallow (3-5 years), tree orchards, and melons; while low in lily and maize fields, and differences in SOC mass followed the same pattern. SOC concentration and mass were lowest in the extensive fields while moderate and intensive fields showed higher values. Soil bulk density in open fields was significantly lower than those in greenhouse and sand-covered fields. The climate-induced soil activity factor r(e_clim) was calculated, compared with European conditions, and was fairly similar to those in central Sweden. Other factors behind the measured results, such as the influence of initial SOC content, manure addition, crops, etc., are discussed.
  • Authors:
    • Hoeppner, F.
    • Fuss, R.
    • Wolf, U.
    • Flessa, H.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 100
  • Issue: 1
  • Year: 2014
  • Summary: Fertilization with biogas residues from the digestion of energy crops is of growing importance. Digestate from silage maize (Zea mays L.) is a new fertilizer with a high potential for ammonia (NH3) and nitrous oxide (N2O) emission. The aim of this study was to determine the effect of different maize fertilization systems [180 kg N ha(-1) in form of calcium nitrate (MIN), biogas digestate from maize (DIG) and biogas digestate from maize mixed with the nitrification inhibitor Piadin (DIG + NI)] on the emission of NH3 and N2O from a sandy soil and to assess the total greenhouse gas emission of these fertilization systems. The study is based on a randomized field plot experiment in central Germany and an experimental period of a full year. Annual N2O-N emission was generally low [0.21 (MIN) to 0.37 (DIG) kg N ha(-1)] without differences between treatments. The application of Piadin reduced N2O emissions by 37 and 62 % during the weeks following digestate application but the annual N2O emission was not affected by the fertilization treatment. NH3 emission was only significant for treatments fertilized with digestate. It was not affected by Piadin and accounted for 27 % (+NI) and 29 % of the applied ammonium. Total greenhouse gas emission was dominated by NH3 losses (reducing the fertilizer value and inducing indirect N2O emissions) for the treatments fertilized with maize digestate. The most important greenhouse gas emission source of the MIN treatment were emissions from fertilizer production. Our results show the high potential of digestate from maize as a new source of NH3 emission. Mitigation measures are essential to save the value of this new fertilizer type and to reduce atmospheric and environmental pollution by direct emission of NH3 and indirect emission of greenhouse gases.