• Authors:
    • Resop, J. P.
    • Sicher, R.
    • Barnaby, J.
    • Fleisher, D. H.
    • Timlin, D. J.
    • Reddy, V. R.
  • Source: AGRONOMY JOURNAL
  • Volume: 106
  • Issue: 6
  • Year: 2014
  • Summary: Elevated carbon dioxide (CO 2) influences photosynthesis ( AN), transpiration (ET), and water use efficiency (WUE) for well-watered potato ( Solanum tuberosum L.). Little is known regarding effects of short-term drought and CO 2. Two experiments, differing in the quantity of solar radiation, were conducted in soil-plant-atmosphere-research chambers. Plants were grown at ambient (aCO 2) or twice-ambient CO 2 (eCO 2) and received one of three irrigation treatments: no water stress (C), short-term (11-16 d) water-withholding during vegetative and post-tuber initiation stages (VR), or post-tuber initiation (R) only. Canopy conductance to CO 2 transfer (tau) and water vapor ( Gv), light use efficiency (alpha), daily AN, and ET decreased at the onset of each drought and were correlated with volumetric water content. The rate of decrease was similar for R and VR. Gv declined more sharply than AN, resulting in higher WUE. Seasonal AN declined with the pattern of C > R > VR and was higher for eCO 2 C and R treatments. Seasonal WUE was higher for eCO 2 at all irrigation treatments. Total dry matter, harvest index, and leaf area were reduced ( p<0.05) for droughted treatments and total dry matter and harvest index were also higher for eCO 2 VR pots. Relative responses to drought and CO 2 were similar among experiments, with greater magnitude of response under high solar radiation. Findings were similar to those reported under longer-term water-withholding studies, suggesting that interactions between CO 2 and drought on carbon assimilation and water use are conserved across production zones with varying radiation and rainfall patterns.
  • Authors:
    • Inubushi, K.
    • Norton, J.
    • Hala, Y.
    • Hiola, S.
    • Jumadi, O.
  • Source: SOIL SCIENCE AND PLANT NUTRITION
  • Volume: 60
  • Issue: 5
  • Year: 2014
  • Summary: Azolla microphylla Kaulf. (Azolla) biomass was composted to create a high nitrogen (N) organic matter amendment (Azolla compost). We examined the effect of this Azolla compost on carbon (C) and N mineralization and the production of biogenic gases, nitrous oxide (N2O) and carbon dioxide (CO2), in a soil incubation experiment. A pot experiment with upland kangkong (Ipomoea aquatica Forsk.) examined plant growth in silt loam soil treated with three levels of Azolla compost. The results showed that N2O production from soil increased with urea amendment, but not with Azolla compost treatments. The Azolla-amended soil showed enhanced CO2 production throughout the 4-week incubation. The Azolla-treated soils showed a 98% lower global warming potential compared to urea treatment over the 4-week incubation. However, Azolla-amended soil had higher nitrate (NO3-) levels compared to urea-fertilized soil at 1 week of incubation, and these were maintained until the fourth week. Soils amended with Azolla compost showed lower ammonium nitrogen (NH4-N) levels than those in the urea-fertilized soils. The height and dry weight of upland kangkong fertilized with Azolla compost were similar to plants receiving urea fertilization. Therefore, the use of Azolla compost as a substitute for urea fertilizer would be beneficial for reducing the production of N2O while maintaining plant growth.
  • Authors:
    • de Cortazar-Atauri,I. G.
    • Huard, F.
    • Bourgeois, G.
    • Caubel, J.
    • Launay, M.
    • Bancal, M. O.
    • Brisson, N.
  • Source: AGRICULTURE ECOSYSTEMS & ENVIRONMENT
  • Volume: 197
  • Year: 2014
  • Summary: Since weather has a major influence on the occurrence and development of crop diseases, valuable insight toward future agricultural planning emerges with assessment tools to evaluate fungal disease pressure and crop regional suitability under projected future climatic conditions. The aim of this study was to develop two climatic indicators, the average infection efficiency (AIE) and the number of infection days (NID), to quantify the potential effects of weather on the intensity and occurrence of pathogen infection. First, a simple and continuous infection function accounting for daily temperature and leaf wetness duration variations was implemented. The function was then parameterized from published data sets for five major contrasting fungal diseases affecting crops in Northern France: phoma of oilseed rape, late blight of potato, downy mildew of grape, leaf rust of wheat and net blotch of barley. Finally, AIE and NID were calculated for the recent past (1970-2000) and the future A1B climate scenario (2070-2100). An overall decrease in the risk of infection was shown for potato late blight and downy mildew of grapevine for all months during the period when the host plant is susceptible to infection. There were greater differences for the other three diseases, depending on the balance between warmer temperatures and lower humidity. The future climate would result in a later onset of disease and higher infection pressure in late autumn. In spring, for brown rust of wheat and net blotch of barley, the climatic risk for infection is expected to occur earlier but would result in lower infection pressure in May. These findings highlighted the need to use an infra-annual (monthly or seasonally) scale to achieve a relevant analysis of the impact of climate change on the infection risk. The described indicators can easily be adapted to other pathogens and may be useful for agricultural planning at the regional scale and in the medium term, when decision support tools are required to anticipate future trends and the associated risks of crop diseases.
  • Authors:
    • Messiga, A. J.
    • Burton, D. L.
    • Hammermeister, A.
    • Lynch, D. H.
    • Sharifi, M.
  • Source: NUTRIENT CYCLING IN AGROECOSYSTEMS
  • Volume: 100
  • Issue: 2
  • Year: 2014
  • Summary: The effects of green manure, crop sequence and off-farm composts on selected soil quality parameters were assessed in a three-year organic potato (Solanum tuberosum L.) rotation in Eastern Canada. Three crop sequences varying in preceding green manure [red clover (RCl) + RCl, and beans/buckwheat or carrots + oats/peas/vetch mixture (OPV)] as main plots and four fertility treatments applied in the potato phase only [control; inorganic fertilizer; municipal solid waste compost (MSW); composted paper mill biosolid (PMB)] as subplots were compared. In 2008 and 2010, changes in selected soil quality parameters (0-15 cm) were assessed prior to planting of potatoes and at potato tuber initiation stage. Potentially mineralizable nitrogen (N) and the acid phosphatase enzyme activity average values across years were greater following RCl (1.51 abs and 622 kg ha(-1)) compared with OPV (1.32 abs and 414 kg ha(-1)) at potato planting. Soil NO3-N average value was greater following RCl compared with OPV (63 vs. 52 kg ha(-1)) at tuber initiation. For the other measured parameters, OPV and RCl were similar. The soil organic carbon (C) and particulate organic matter-C were greater under PMB and MSW (31.1 and 7.57 kg ha(-1)) compared with fertilizer treatment (27.9 and 6.05 kg ha(-1)). The microbial biomass C and microbial biomass quotient were greater under MSW (216 kg ha(-1) and 0.73 %) than PMB and fertilizer (147 kg ha(-1) and 0.50 %) across crop rotations. Annual legume green manures and off-farm composts can be used to satisfy potato N requirement and maintains soil quality in organic potato rotations.
  • Authors:
    • Garrett, K. A.
    • Hijmans, R. J.
    • Forbes, G. A.
    • Sparks, A. H.
  • Source: GLOBAL CHANGE BIOLOGY
  • Volume: 20
  • Issue: 12
  • Year: 2014
  • Summary: Weather affects the severity of many plant diseases, and climate change is likely to alter the patterns of crop disease severity. Evaluating possible future patterns can help focus crop breeding and disease management research. We examined the global effect of climate change on potato late blight, the disease that caused the Irish potato famine and still is a common potato disease around the world. We used a metamodel and considered three global climate models for the A2 greenhouse gas emission scenario for three 20-year time-slices: 2000-2019, 2040-2059 and 2080-2099. In addition to global analyses, five regions were evaluated where potato is an important crop: the Andean Highlands, Indo-Gangetic Plain and Himalayan Highlands, Southeast Asian Highlands, Ethiopian Highlands, and Lake Kivu Highlands in Sub-Saharan Africa. We found that the average global risk of potato late blight increases initially, when compared with historic climate data, and then declines as planting dates shift to cooler seasons. Risk in the agro-ecosystems analyzed, varied from a large increase in risk in the Lake Kivu Highlands in Rwanda to decreases in the Southeast Asian Highlands of Indonesia.
  • Authors:
    • Vallejo, A.
    • van Groenigen, J. W.
    • Garcia-Torres, L.
    • Sanchez-Martin, L.
    • Abalos, D.
  • Source: SCIENCE OF THE TOTAL ENVIRONMENT
  • Volume: 490
  • Year: 2014
  • Summary: Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH4+ and NO3-) regulating the emissions of greenhouse gases (i.e. N2O, CO2 and CH4) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N2O, NO, CH4 and CO2 were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N2O and NO emissions by a factor of 2.4 and 2.9, respectively (P < 0.005). Daily irrigation reduced NO emissions by 42% (P < 0.005) but increased CO2 emissions by 21% (P < 0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N2O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO3--based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation. (C) 2014 Elsevier B.V. All rights reserved.
  • Authors:
    • Capriel, P.
  • Source: European Journal of Soil Science
  • Volume: 64
  • Issue: 4
  • Year: 2013
  • Summary: In the last 60 years traditional agriculture in industrialized European countries, which had initially been dependent on available natural resources, has shifted towards a massive intensification of nutrient turnover because of cheap energy and low-cost synthetic fertilizers. At the same time farm structure has undergone profound changes, resulting in an increase in the number of specialized farms to the detriment of traditional non-specialized ones. All these trends have had a significant impact on agricultural management. The intensification of agricultural management together with climate change could affect the quantity and quality of soil organic matter (SOM). That could imply decreasing soil fertility, reduced harvest yields, increasing nutrient losses and additional greenhouse gas emission. In order to measure the long-term development of SOM in agricultural soils a monitoring programme was initiated in Bavaria in 1986. The measurements are based on 92 representative plots located on cropland and 21 plots located on managed permanent grassland. Between 1986 and 2007 the monitoring plots have been sampled four times. The monitoring results suggest a decrease of soil organic carbon content, total nitrogen content and C:N ratio in cropland as well as in grassland in Bavaria between 1986 and 2007. Crops and organic fertilizers are together with the initial SOM content the main causes of the observed changes in SOM quantity and quality. A climatic effect could be neither proved nor excluded. The results in Bavaria are consistent with the reported changes in organic carbon of agricultural soils in Austria, Belgium, France, the Netherlands and England. In Bavaria we should expect declining SOM stocks, particularly soil organic carbon, in agricultural soils if the supply of organic matter remains constant or even decreases.
  • Authors:
    • van Evert, F. K.
    • de Ruijter, F. J.
    • Haverkort, A. J.
    • Conijn, J. G.
    • Rutgers, B.
  • Source: Potato Research
  • Volume: 56
  • Issue: 4
  • Year: 2013
  • Summary: Potato and its derivatives increasingly become globally traded products. Commercial companies more and more want to quantify the environmental footprints such as the efficiency of the use of land and water, greenhouse gas emissions, and the risks of eutrophication and contamination of the environment with pesticides. From various sources, global maps with grid cells of circa 8,600 ha (near the equator) were drawn representing potato-harvested area, potato fresh tuber yield (land use efficiency), slopes (risks of erosion), precipitation deficit (risks of depletion of fresh water resources through irrigation), and average daily maximum temperature throughout the season (risks of occurrence of pest epidemics and emission of pesticides). Hotspots for erosion are the slopes of the mountains in the Andes, African Rift, Southern China and volcanic areas in southern China, and the island countries in Southeast Asia. Fresh water availability may become limited in the East of North America, northern India, and China. Risks of insects are increased in continental hot summer climates and short spring crops with high temperatures towards harvest. Late blight is a threat in all humid areas such as maritime Europe, equatorial tropical highlands, and the humid western Pacific Ring. The examples discussed in this paper can be elaborated for more soil and weather-related factors such as acidity and salinity and heat waves or torrential rains. Sustainable long-term and long-range sourcing is deliberated as well as repercussions of trends such as globalization and climate change; the latter being relative favorable for the root and tuber crop potato compared to grain crops.
  • Authors:
    • Chow, T. L.
    • Damboise, J.
    • Lantz, V. A.
    • Olale, E.
    • Ochuodho, T. O.
    • Meng, F.
    • Daigle, J. L.
    • Li, S.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 68
  • Issue: 5
  • Year: 2013
  • Summary: We investigated the effects of soil and water conservation practices on mean and variance of potato (Solanum tuberosum L.) yield across 267 fields in northwestern New Brunswick, Canada, from 1988 to 2010. A stochastic production function method was used to account for seven soil and water conservation practices in addition to farm inputs, potato varieties, technological change, site characteristics, and seasonal climate effects. Overall, soil and water conservation structures had mixed effects on potato yield.While spring tillage and terracing increased mean potato yield, grassed waterways, drainage, chisel plowing, and other practices had the opposite effect. Rock management did not impact mean potato yield. Most practices did not impact yield variance. While soil and water conservation practices can be effective farm management tools for maintaining soil fertility and enhancing potato yields, there are no one-size-fits-all prescriptions to enhance yield.
  • Authors:
    • Zhao, J.-S.
    • Hu, R.-G.
    • Iqbal, J.
    • Lin, S.
  • Source: Pedosphere
  • Volume: 23
  • Issue: 5
  • Year: 2013
  • Summary: To compare the CH4 oxidation potential among different land uses and seasons, and to observe its response to monsoon precipitation pattern and carbon and nitrogen parameters, a one-year study was conducted for different land uses (vegetable field, tilled and non-tilled orchard, upland crops and pine forest) in central subtropical China. Results showed significant differences in CH4 oxidation potential among different land uses (ranging from -3.08 to 0.36 kg CH4 ha(-1) year(-1)). Upland with corn-peanut-sweet potato rotation showed the highest CH4 emission, while pine forest showed the highest CH4 oxidation potential among all land uses. Non-tilled citrus orchard (-0.72 +/- 0.08 kg CH4 ha(-1) year(-1)) absorbed two times more CH4 than tilled citrus orchard.(-0.38 +/- 0.06 kg CH4 ha(-1) year(-1)). Irrespective of different vegetation, inorganic N fertilizer application significantly influenced CH4 fluxes across the sites (R-2 = 0.86, P = 0.002). Water-filled pore space, soil microbial biomass carbon, and dissolved nitrogen showed significant effects across different land uses (31% to 38% of variability) in one linear regression model. However, their cumulative interaction was significant for pine forest only, which might be attributed to undisturbed microbial communities legitimately responding to other variables, leading to net CH4 oxidation in the soil. These results suggested that i) natural soil condition tended to create win-win situation for CH4 oxidation, and agricultural activities could disrupt the oxidation potentials of the soils; and ii) specific management practices including but not limiting to efficient fertilizer application and utilization, water use efficiency, and less soil disruption might be required to increase the CH4 uptake from the soil.