• Authors:
    • Sheaffer, C. C.
    • Fernandez, A. L.
    • Wyse, D. L.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Field pea ( Pisum sativum L.) and lentil ( Lens culinaris Medik.) have potential as grain-producing legumes in organic rotations, but their yield is limited by weed competition. Intercropping can control weeds and increase total grain productivity per land area compared to sole cropping. A field experiment was conducted to investigate the effect of intercropping on field pea and lentil yields. Intercrop treatments were spring wheat ( Triticum aestivum L.), oat ( Avena sativa L.), and radish ( Raphanus sativus L.), which were harvested for grain; and winter rye ( Secale cereale L.) and rapid-cycling brassica ( Brassica campestris L.), which were not harvested. Intercropped lentil yields and total (lentil plus intercrop) yields were lower than or equal to weeded and unweeded sole cropped lentils in 5 of 6 site-years. Intercropped pea yields and total (pea plus intercrop) yields were lower than or equal to weeded and unweeded sole cropped pea in all site-years. Unharvested intercrops showed variable effectiveness at suppressing weeds. In lentil, winter rye intercropping reduced weed biomass compared to the unweeded control in 4 site-years, and rapid-cycling brassica reduced weed biomass in 2 site-years. In pea, winter rye, and rapid-cycling brassica treatments reduced weed biomass in all site-years. However, reductions in weed biomass were not associated with increases in grain yield. Estimated net returns to intercropping were variable, but generally similar for sole crops and intercrops on average. We did not observe consistent agronomic or economic advantages to the use of intercrops with field pea and lentil in the Minnesota environments studied.
  • Authors:
    • Gao XiaoPeng
    • Asgedom,H.
    • Tenuta,M.
    • Flaten,D. N.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: The effects of band placement of enhanced efficiency fertilizers (EEF) on nitrous oxide (N 2O) emissions are uncertain. Placement and EEF on N 2O emissions from spring wheat ( Triticum aestivum L.) at two locations in Manitoba, in 2011 and 2012 were examined. Treatments were a no N control and 80 kg N ha -1 at planting of five combinations of placement and granular N source: broadcast-incorporated urea (Urea I) and, subsurface side-banded urea (Urea S; each row side-banded), midrow-banded urea (Urea M; placement between every other set of rows), midrow-banded environmentally smart nitrogen (ESN, Agrium, Inc.) (ESN M), and midrow-banded SuperU (Koch Industries Inc.) (SuperU M). Planting in 2011 was delayed 40 d compared to 2012. Planting coincided with higher soil temperature and moisture resulting in three- to sevenfold more growing season N 2O emissions (SigmaN 2O) in 2011 than 2012. In 2011, SuperU M and ESN M reduced SigmaN 2O, emission factor (EF) scaled by N-applied EF, and yield-scaled N 2O emission intensity (EI) by 47, 67, and 55%, respectively, compared with Urea I. In 2011, increasing placement concentration of N in order broadcast-incorporation, side-banding, and midrow-banding tended to decrease SigmaN 2O, EF, and EI of granular urea, but not statistically significant. The SigmaN 2O and nitrate exposure (NE), were significantly correlated over the site-years, indicating N availability from treatments in part determined emissions. Grain yield and crop N uptake were unaffected by sources and placement. These results suggest for early season wet and warm conditions, EEF N sources can reduce emissions compared with granular urea. Further studies are required to clarify placement effects on N 2O emissions.
  • Authors:
    • Fransen, S.
    • Okwany, R. O.
    • Girma, K.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Managing the soil profile NO 3-N through crop selection and irrigation is an important consideration for the sustainable production of cellulosic biofuel feedstock crops. Data from two seasons were collected and analyzed from a 4-yr study conducted in Prosser, WA, to assess the effect of biofuel feedstock grasses and irrigation levels on soil profile NO 3-N. The experimental design was a split plot with three replications. The main plots had three irrigation levels (60, 80, and 100% evapotranspiration, ET), and the subplots contained three cultivars of switchgrass ( Panicum virgatum L.) and gamagrass ( Tripsacum dactyloides L.) cultivars. Soil and root samples were collected in fall 2011 (Season1) and winter of 2012 (Season2). Soil profile NO 3-N concentrations were highest at the lowest irrigation levels. In Season1, the soil profile NO 3-N concentration averaged over depths was 1.7 mg kg -1 for the switchgrass cultivars and 5.6 mg kg -1 for gamagrass. In Season2, the concentrations were 1.4 and 2.2 mg kg -1 for the switchgrass cultivars and gamagrass, respectively. We found a significant correlation between switchgrass root mass and soil profile NO 3-N; r=0.63-Kanlow; r=0.58-Blackwell; and r=0.46-Shawnee. Our results suggest that soil profile NO 3-N was lower under the switchgrass cultivars than gamagrass. More root mass and NO 3-N were accumulated at lower irrigation levels. The results reported here can help in developing practical decision tools for managing fertilizer N in biomass biofuel crops.
  • Authors:
    • Gizaw, Mesgana
    • Gan, Thian Yew
    • Kuo, Chun-Chao
  • Source: Article
  • Volume: 130
  • Issue: 2
  • Year: 2015
  • Summary: Under the effect of climate change, warming likely means that there will be more water vapour in the atmosphere and extreme storms are expected to occur more frequently and with greater severity, resulting in municipal Intensity-Duration-Frequency (IDF) curves with higher intensities and shorter return periods. A regional climate model, MM5 (the Pennsylvania State University / National Center for Atmospheric Research numerical model), was set up in a one-way, three-domain nested framework to simulate future summer (May to August) precipitation of central Alberta. MM5 is forced with climate data of four Global Climate Models, CGCM3, ECHAM5, CCSM3, and MIROC3.2, for the baseline 1971-2000 and 2011-2100 based on the Special Report on Emissions Scenarios A2, A1B, and B1 of Intergovernmental Panel on Climate Change. Due to the bias of MM5's simulations, a quantile-quantile bias correction method and a regional frequency analysis is applied to derive projected grid-based IDF curves for central Alberta. In addition, future trends of air temperature and precipitable water, which affect storm pattern and intensity, are investigated. Future IDF curves show a wide range of increased intensities especially for storms of short durations (a parts per thousand currency sign1-h). Conversely, future IDF curves are expected to shift upward because of increased air temperature and precipitable water which are projected to be about 2.9 A degrees C and 29 % in average by 2071-2100, respectively. Our results imply that the impact of climate change could increase the future risk of flooding in central Alberta.
  • Authors:
    • Johnson-Maynard, J. L.
    • Lentz, R. D.
    • Brown, B.
    • Lehrsch, G. A.
    • Leytem, A. B.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: To grow sugarbeet ( Beta vulgaris L.) profitably, producers must effectively manage added N, whether from inorganic or organic sources. Our objective was to determine if equivalent sugarbeet root and sucrose yields could be achieved when substituting dairy cattle ( Bos spp.) manure, either composted or stockpiled, for conventional N (urea) fertilizer. First-year treatments at Site A (Parma, ID) included a control (no N), urea (202 kg N ha -1), compost (218 and 435 kg estimated available N ha -1), and manure (140 and 280 kg available N ha -1). Site B (Kimberly, ID) treatments were a control, urea (82 kg N ha -1), compost (81 and 183 kg available N ha -1), and manure (173 and 340 kg available N ha -1). Compost and manure were incorporated into two silt loams, a Greenleaf (fine-silty, mixed superactive mesic Xeric Calciargid) at Parma in fall 2002 and 2003 and a Portneuf (coarse-silty, mixed superactive, mesic Durinodic Xeric Haplocalcid) at Kimberly in fall 2002. Sugarbeet was planted the following spring. Sucrose yield averaged across years and organic N rates at Site A was 12.24 Mg ha -1 for urea, 11.88 Mg ha -1 for compost, and 11.20 Mg ha -1 for manure, all statistically equivalent. Doubling the organic N rates at Site A increased the yield of roots up to 26% and sucrose up to 21%. Applying organic amendments in place of urea affected neither root nor sucrose yields but, at one location, decreased sugarbeet quality, though without hindering sucrose recovery. Sugarbeet producers can use compost or manure to satisfy crop N needs without sacrificing sucrose yield.
  • Authors:
    • Prokopy,Linda Stalker
    • Carlton,J. Stuart
    • Arbuckle,J. Gordon, Jr.
    • Haigh,Tonya
    • Lemos,Maria Carmen
    • Mase,Amber Saylor
    • Babin,Nicholas
    • Dunn,Mike
    • Andresen,Jeff
    • Angel,Jim
    • Hart,Chad
    • Power,Rebecca
  • Source: Climatic Change
  • Volume: 130
  • Issue: 2
  • Year: 2015
  • Summary: The U.S. Cooperative Extension Service was created 100 years ago to serve as a boundary or interface organization between science generated at the nation's land grant universities and rural communities. Production agriculture in the US is becoming increasingly complex and challenging in the face of a rapidly changing climate and the need to balance growing crop productivity with environmental protection. Simultaneously, extension budgets are diminishing and extension personnel are stretched thin with numerous, diverse stakeholders and decreasing budgets. Evidence from surveys of farmers suggests that they are more likely to go to private retailers and consultants for information than extension. This paper explores the role that extension can play in facilitating climate change adaptation in agriculture using data from a survey of agricultural advisors in Indiana, Iowa, Michigan and Nebraska and a survey of extension educators in the 12 state North Central Region. Evidence from these surveys shows that a majority of extension educators believe that climate change is happening and that they should help farmers prepare. It also shows that private agricultural advisors trust extension as a source of information about climate change. This suggests that extension needs to continue to foster its relationship with private information providers because working through them will be the best way to ultimately reach farmers with climate change information. However extension educators must be better informed and trained about climate change; university specialists and researchers can play a critical role in this training process.
  • Authors:
    • Reibe,K.
    • Gotz,K. P.
    • Ross,C. L.
    • Doring,T. F.
    • Ellmer,F.
    • Ruess,L.
  • Source: Soil Biology & Biochemistry
  • Volume: 83
  • Year: 2015
  • Summary: The effects of biochar (maize biochar - MBC, wood biochar - WBC) and unfermented or fermented hydrochar (HTC) on the euedaphic Collembola Protaphorura fimata and on spring wheat were investigated in greenhouse experiments. The impact of char type, amount of fermented HTC, and MBC-Collembola interactions were assessed. Generally, shoot and root biomass as well as abundance of P. fimata were not affected by the different chars. However, with increasing amounts of fermented HTC the abundance of P. fimata declined, whereas shoot biomass of wheat increased. Moreover, MBC altered root morphology and resulted in thicker roots with higher volume. The latter was not apparent when Collembola were present.
  • Authors:
    • Weber-Blaschke, G.
    • Lampert, P.
    • Soode, E.
    • Richter, K.
  • Source: Agriculture Article
  • Volume: 87
  • Year: 2015
  • Summary: Global climate change problem can be linked to production efficiency and everyday consumption patterns by calculating the greenhouse gas emissions resulting from each product. This is usually referred to as product carbon footprint (PCF). Only limited information is available about the PCF of German horticultural products. We measured the cradle-to-grave PCF of German strawberries, asparagus, roses and orchids in different production systems and compared it to the PCF of the same products grown in other countries. For the production and customer stage we collected primary data, for the comparison with products in other countries we used literature data. The results showed that the average consumer stage constitutes 3-71% of the PCF, the best case consumer scenario 1-39% and the worst case 60-99%. The consumer shopping trip was a hotspot in all analysed systems where a private car was used. Electricity for production, fuel use for soil management, and cooking and washing dishes were also among the most often identified hotspots. German open field strawberries perform better, German open field roses and asparagus are on the similar level with the same products produced abroad. However, asparagus transported by plane, and strawberries and roses grown in greenhouses have several times higher PCF regardless of the producing country. Consumers as well as producers are responsible for reducing the climate impact of horticultural products. Shopping trip on foot or by bike and using renewable energy can reduce the PCF significantly. We recommend extending the analysis to the life cycle assessment or product environmental footprint to consider more indicators to identify which products are less harmful to the environment.
  • Authors:
    • Lobell, D.
    • Schlenker, W.
    • Roberts, M.
    • Urban, D.
  • Source: Journal
  • Volume: 130
  • Issue: 2
  • Year: 2015
  • Summary: Short durations of very high spring soil moisture can influence crop yields in many ways, including delaying planting and damaging young crops. The central United States has seen a significant upward trend in the frequency and intensity of extreme precipitation in the 20th century, potentially leading to more frequent occurrences of saturated or nearly saturated fields during the planting season, yet the impacts of these changes on crop yields are not known. Here we investigate the yield response to excess spring moisture for both maize and soybean in the U.S. states of Illinois, Iowa, and Indiana, and the impacts of historical trends for 1950-2011. We find that simple measures of extreme spring soil moisture, derived from fine-scale daily moisture data from the Variable Infiltration Capacity (VIC) hydrologic model, lead to significant improvements in statistical models of yields for both crops. Individual counties experience up to 10 % loss in years with extremely wet springs. However, losses due to historical trends in excess spring moisture measures have generally been small, with 1-3 % yield loss over the 62 year study period.
  • Authors:
    • Coulter, J. A.
    • Venterea, R. T.
  • Source: Agronomy Journal
  • Volume: 107
  • Issue: 1
  • Year: 2015
  • Summary: Modification of N fertilizer application timing within the growing season has the potential to reduce soil nitrous oxide (N 2O) emissions but limited data are available to assess its effects. We compared cumulative growing season nitrous oxide emissions (cN 2O) following urea applied to corn ( Zea mays L.) in a single application (SA) at planting or in three split applications (SpA) over the growing season. For both SA and SpA, granular urea was broadcast and incorporated at six fertilizer N rates in the corn phase of a corn-soybean [ Glycine max (L.) Merr.] rotation and in a continuous corn system over two growing seasons. Daily N 2O flux was measured using chambers on 35 dates in 2012 and 40 dates in 2013 and soil nitrate-N concentration was measured weekly. Split application did not affect grain yield and did not reduce cN 2O. Across N rates and rotations, cN 2O was 55% greater with SpA compared with SA in 2012. Increased cN 2O with SpA in 2012 likely resulted from a prolonged dry period before the second split application followed by large rainfall events following the third split application. Across years and rotations, SpA increased cN 2O by 57% compared with SA when the maximum N rate was applied. Exponential relationships between cN 2O and fertilizer N rate explained 62 to 74% of the variance in area-based cN 2O and 54% of the variance in yield-based cN 2O. Applying urea to coincide with periods of high crop N demand does not necessarily reduce and may increase N 2O emissions.