• Authors:
    • Fitt, B. D. L.
    • Stevens, M.
    • Townsend, J. A.
    • West, J. S.
  • Source: European Journal of Plant Pathology
  • Volume: 133
  • Issue: 1
  • Year: 2012
  • Summary: This review describes environmental factors that influence severity of crop disease epidemics, especially in the UK and north-west Europe, in order to assess the effects of climate change on crop growth and yield and severity of disease epidemics. While work on some diseases, such as phoma stem canker of oilseed rape and fusarium ear blight of wheat, that combine crop growth, disease development and climate change models is described in detail, climate-change projections and predictions of the resulting biotic responses to them are complex to predict and detailed models linking climate, crop growth and disease development are not available for many crop-pathogen systems. This review uses a novel approach of comparing pathogen biology according to 'ecotype' (a categorization based on aspects such as epidemic type, dissemination method and infection biology), guided by detailed disease progress models where available to identify potential future research priorities for disease control. Consequences of projected climate change are assessed for factors driving elements of disease cycles of fungal pathogens (nine important pathogens are assessed in detail), viruses, bacteria and phytoplasmas. Other diseases classified according to 'ecotypes' were reviewed and likely changes in their severity used to guide comparable diseases about which less information is available. Both direct and indirect effects of climate change are discussed, with an emphasis on examples from the UK, and considered in the context of other factors that influence diseases and particularly emergence of new diseases, such as changes to farm practices and introductions of exotic material and effects of other environment changes such as elevated CO2. Good crop disease control will contribute to climate change mitigation by decreasing greenhouse gas emissions from agriculture while sustaining production. Strategies for adaptation to climate change are needed to maintain disease control and crop yields in north-west Europe.
  • Authors:
    • Coleman, K.
    • Dailey, A. G.
    • Glendining, M. J.
    • Goulding, K. W. T.
    • Whitmore, A. P.
    • Powlson, D. S.
  • Source: Sustainability
  • Volume: 4
  • Issue: 10
  • Year: 2012
  • Summary: Given that we must farm land in order to eat, the total environmental burden imposed by farming a crop, such as winter wheat in the UK, appears to be close to the minimum given current production techniques. The value of the services other than food production, such as flood water buffering, pollination, carbon storage and so on, that land can provide is relatively large compared with the value in reducing environmental burdens from pesticide use, nutrient pollution and greenhouse gas emissions that might arise by farming less intensively. More land will need to be brought into cultivation in order to provide the same amount of food if the intensity of farming is reduced and the resultant loss of ecosystem services (ES) outweighs the reduction in other burdens. Nevertheless, losses of nutrients, especially nitrogen (N), from agriculture are a serious concern and the current cost of the environmental footprint of agriculture is significant compared with the value of the food it produces. This article examines nutrient burdens and analyses the means by which the total environmental burden might be reduced relative to productivity. These include increasing the efficiency of farming, removing constraints to yield, and establishing multiple uses for land at the same time as farming. It concludes that agronomic measures which improve nutrient capture and which obtain more yield per unit area are valuable means to avoid degradation of environmental quality because both nutrient pollution and land consumption can be avoided.
  • Authors:
    • Six, J.
    • Tian,Jing
    • Kuzyakov, Y.
    • Lee, J.
    • Chen, H.
    • Christie, P.
    • Li, X.
    • Zhang, F.
    • Fan, M.
    • Yan, Y.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 150
  • Year: 2012
  • Summary: The conversion from cereal fields to vegetable production in the last three decades represents a significant shift in land use in China. Here, we studied the effects of conversion form cereal fields to vegetable production in north China on soil organic carbon (SOC) and total nitrogen (TN) in both bulk soil and soil aggregates. We used two approaches: (1) measurements of paired soil samples from wheat (Triticum aestivum L) - maize (Zea mays L) fields and adjacent greenhouses vegetable fields in three vegetable production areas representing various management intensities in terms of C and N inputs and frequency of tillage: (2) fractionating soil to distinguish intra-aggregate particulate organic matter (iPOM) and organo-mineral complexes (silt + clay). Our results indicated that converting cereal fields to greenhouse vegetable production with intermediate and high management intensity led to increases in SOC and TN and decreases in C:N ratios in the top soil. The accumulation rates of C and N in the surface soil (0-30 cm) were estimated to be 1.37 Mg C ha(-1) yr(-1) and 0.21 Mg N ha(-1) yr(-1) over an average period of 8 years after cereal fields to greenhouse vegetable production conversion. At the soil aggregate level, only the coarse (>250 mu m) and fine (53-250 mu m) iPOM fraction contributed to the increases in soil C (e.g., 49% and 51% of total C increases, respectively), while the coarse and fine iPOM, and silt + clay fraction accounted for 22%, 30% and 48%, respectively, of total N increases. This illustrates how the addition of readily available C (manure) and N (manure and inorganic N) leads to a temporary stabilization of C in relatively labile SOM fractions, but to a preferential stabilization of N in organo-mineral SOM fractions. In conclusion, the conversion to highly intensive vegetable systems in China leads to marked differences in C and N stabilization dynamics.
  • Authors:
    • Chen, C.
    • Yang, M.
    • Zhu, L.
  • Source: Journal of Agricultural Science
  • Volume: 4
  • Issue: 9
  • Year: 2012
  • Summary: Carbon sequestration in cropland soils which could be achieved through improved management practices (IPMs) represents an important opportunity to offset a portion of greenhouse gas emissions. North China is the main wheat and maize production region where many IMPs have been widely used during the last several decades, but the effect size and duration of IMPs on soil organic carbon (SOC) sequestration in wheat-maize double cropping system in this region is scarcely studied. In this study, a meta-analysis was conducted to compare the effect size and duration of four IMPs on SOC sequestration in wheat-maize double cropping system in north China. A total of 29 long-term experiments, consisting of 119 paired treatments were compiled in this analysis. The results indicated that the four IMPs of organic manure application (OM), organic manure combined with chemical fertilizer application (MF), straw return (SR) and reduced or no tillage (RNT) all had significant effects on SOC sequestration in the study area. On average, the IMPs of OM, MF, SR and RNT enhanced SOC density by 260, 328, 278 and 134 kg ha -1 yr -1, respectively. The effect duration of OM, MF, SR and RNT on SOC sequestration were about 48, 26, 22 and 18 years, respectively. Accumulation enhancements of SOC for OM, MF, SR and RNT over SOC sequestration period were about 34.7%, 36.1%, 22.0% and 12.7%, respectively. OM and MF could be the appropriate practices on SOC sequestration in wheat-maize double cropping system in the research area.
  • Authors:
    • Daughtry, C. S. T.
    • Vigil, M.
    • Evans, R.
    • Aguilar, J.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: Crop residue is important for erosion control, soil water storage, filling gaps in various agroecosystem-based modeling, and sink for atmospheric carbon. The use of remote sensing technology provides a fast, objective, and efficient tool for measuring and managing this resource. The challenge is to distinguish the crop residue from the soil and effectively estimate the residue cover across a variety of landscapes. The objective of this study is to assess a select Landsat Thematic Mapper (TM) and hyperspectral-based indices in estimating crop residue cover and amount for both standing and laid flat, and between two winter wheat ( Triticum aestivum L.) harvest managements (i.e., stripper-header and conventional header) and fallow following proso-millet ( Panicum miliaceum L.) plots. The primary plots were located in Colorado with additional plots in eastern Montana, Oregon, and Washington states. Data collected include hyperspectral scans, crop residue amount (by weight) and residue cover (by photo-grid). Mean analyses, correlation tests, and spectral signature comparison show that the relative position of the crop residues affected the values of some remote sensing indices more than harvest management. Geographical location did not seem to influence the results. There was not enough evidence to support the use of these indices to accurately estimate the amount of residue. Hyperspectral data may deliver better estimates, but in its absence, the use of two or more of these datasets might improve the estimation of residue cover. This information will be useful in guiding analysis of remotely sensed data and in planning data acquisition programs for crop residue, which are essentially nonexistent at present.
  • Authors:
    • Leithold, G.
    • Hoyer, U.
    • Brock, C.
    • Hulsbergen, K. J.
  • Source: Nutrient Cycling in Agroecosystems Pages:
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: With this paper we present a simple model for the assessment of management impact in arable farming systems on soil organic matter (SOM) levels. The humus balance model (HU-MOD) is designed for application by farmers and extension workers in practice as a tool for management support. To enable practice applicability, HU-MOD bypasses the need for data on soil parameters and can be run with simple management data. HU-MOD is based on a simplified model on carbon and nitrogen pools and fluxes in the soil-plant system. The model proved to be an applicable simple tool for the comparison of management systems in arable farming with regard to the impact on SOM levels. Even though an absolute quantification of SOM level changes is not possible due to the methodical approach bypassing the need for any data on soil parameters, the model may be used to assess a positive or negative impact of a management system or management period compared to a reference and thus may be used to assess the impact of management changes, or to analyse a specific impact for different management periods on a defined spatial unit.
  • Authors:
    • Takebe, M.
    • Karasawa, T.
  • Source: Plant and Soil
  • Volume: 353
  • Issue: 1-2
  • Year: 2012
  • Summary: Aims A field experiment was conducted where maintenance of indigenous arbuscular mycorrhizal (AM) fungal populations was attempted using AM host cover crops arranged temporally or spatially during growth of nonmycorrhizal crops. Methods To arrange AM hosts temporally, sunflower or oat was grown as a cover crop after non-host cropping (cabbage) or fallowing. In order to arrange AM hosts spatially, red clover, white clover or vetch was intercropped during growth of non-host cabbage. Results The AM colonization and growth of maize with previously introduced sunflower or oat were much greater than those without introduction of cover crops or those with introduction of non-host cover crops. The AM colonization and yield of winter wheat grown after cabbage with AM host intercropping were greater than those after cabbage only cropping, suggesting that arrangement of AM hosts between cabbage rows is effective for maintaining the AM fungal population in soil during non-host cropping. Conclusions Mycorrhizal hosts cropped after or during non-host cropping is an effective means to increase indigenous AM fungal populations. The results show that AM colonization, P uptake and productivity of crops after cultivation of nonmycorrhizal crops can be improved by arranging AM hosts temporally or spatially as cover crops.
  • Authors:
    • Baetens, J. M.
    • Vandepitte, J.
    • Audenaert, K.
    • Waegeman, W.
    • Landschoot, S.
    • De Baets, B.
    • Haesaert, G.
  • Source: Journal of Plant Pathology
  • Volume: 94
  • Issue: 1
  • Year: 2012
  • Summary: Models for predicting Fusarium head blight (FHB) and deoxynivalenol (DON) content in wheat provide farmers with a tool for preventing yield loss and mycotoxin contamination. Due to the complex nature of FHB, these models typically take only a subset of explanatory variables as inputs, such as weather conditions during anthesis and, to a lesser extent, field-specific variables and crop characteristics. We present a thorough statistical analysis of a broad spectrum of variables that affect FHB and DON content, using an unique database of field observations covering nine years. This study unveils new variables that play an important role in FHB incidence and DON content. Evidence is brought forward demonstrating the effect of species interactions on DON content and the effect of weather conditions during the vegetative growth stage. Indeed, temperature from November till May was positively correlated with FHB and DON content, whereas relative humidity was negatively correlated with DON content in November and December. In a broader view of the divergent results obtained regarding FHB and DON content in wheat crops, this study underscores that the prediction of FHB and DON content should be seen as two distinct goals.
  • Authors:
    • Al-Amoud, A. I.
    • Alabdulkader, A. M.
    • Awad, F. S.
  • Source: Agricultural Economics – Czech
  • Volume: 58
  • Issue: 2
  • Year: 2012
  • Summary: A mathematical sector model has been formulated to optimize the cropping pattern in Saudi Arabia aiming at maximizing the net annual return of the agricultural sector in the country and ensuring the efficient allocation of the scarce water resources and arable land among the competing crops. The results showed the potential for Saudi Arabia to optimize its cropping pattern and to generate an estimated net return equivalent to about 2.42 billion US$ per year. The optimized cropping pattern in Saudi Arabia has been coupled with about 53% saving in water use and about 48% reduction in the arable land use compared to the base-year cropping pattern. Comparable weights was given to different crop groups by allocating about 48.4%, 35.4%, 13.1%, and 3.2% to grow cereals, fruits, forages, and vegetables, respectively. These findings are in line with the national strategy to rationalize the cultivation of water-intensive crops in favour of highly water-efficient crops.
  • Authors:
    • Taha, A. S.
    • Muneer, S. E.
    • Alzahrani, K. H.
    • Baig, M. B.
  • Source: JAPS, Journal of Animal and Plant Sciences
  • Volume: 22
  • Issue: 1
  • Year: 2012
  • Summary: Fresh water is one of the most important and scarcest natural resources around the globe. In Saudi Arabia fresh water shortage for different uses represents one of the main challenges hindering development efforts in the country. As such there is a need to pursue a water demand management policy which should include any measure or initiative that will result in reduction of water usage and/or water demand. This study is intended to explore the potential of proper cropping pattern as a water demand management tool to enhance water and food security in Saudi Arabia. Secondary data were obtained from the ministry of Agriculture and Ministry of Electricity and Water. The analyses revealed that existing cropping pattern did not benefit from the relative advantage of different regions in producing different crops. Thus, there is a great potential for enhancing food and water security in Saudi Arabia through altering existing cropping pattern by encouraging production of different crops in the regions that have clear relative advantage in their production i.e. give the highest productivity. For example production of cereals could be concentrated in Jouf and Tabuk areas, while vegetables production in the eastern region and Asser area.