• Authors:
    • Martin, E. C.
    • Subramani, J.
  • Source: Applied Engineering in Agriculture
  • Volume: 28
  • Issue: 1
  • Year: 2012
  • Summary: In 2001, the Arizona Department of Water Resources implemented an agricultural Best Management Practice (BMP) program. The program was designed to encourage the use of BMPs in irrigation with the goal of increasing the efficient use of water resources on the farm. Several BMPs were identified through meetings with stakeholders, researchers, and scientists. One of the BMPs identified was alternate furrow irrigation. This three-year study was designed to determine the impact of alternate furrow irrigation on surface irrigation water applications and cotton yield. There were two treatments, every furrow (EF) and every other furrow (EOF). Lint yields were 1794 and 1694 kg/ha in 2006; 1795 and 1902 kg/ha in 2007; and 1365 and 1237 kg/ha in 2008 for the EF and EOF treatments, respectively. Seasonal irrigation water applications were 187.7 and 162.3 cm in 2006; 151.4 and 137.2 cm in 2007; and 184.1 and 132.6 cm in 2008 for EF and EOF treatments, respectively. The results indicate that an average of 30.5 cm of water can be saved by the implementation of an alternate furrow irrigation scheme without significantly reducing lint yield.
  • Authors:
    • Albrigo, L. G.
    • Syvertsen, J. P.
    • Melgar, J. C.
  • Source: Acta Horticulturae
  • Issue: 928
  • Year: 2012
  • Summary: The loss of leaves, branches and flowers along with bark scuffing and root exposure that can occur during mechanical harvesting (MH) has not reduced long term yields of healthy trees. Nonetheless, such visible injuries have limited the widespread adoption of mechanical harvesting in Florida's citrus industry. There was little measurable physiological stress from MH in healthy, well-managed trees as leaf water relations, CO 2 assimilation and final yield were not affected. The abscission compound CMNP, can effectively reduce fruit detachment force and result in fewer visible injuries. Late season MH of 'Valencia' sweet orange remains a major problem when young fruitlets for next crop become large enough to be harvested prematurely. We determined if winter drought stress from January to March could delay flowering and fruitlet development so they would be too small to be susceptible mechanical harvesting. Drought stress during winter delayed flowering 2-3 weeks, reduced flowering and vegetative growth but did not reduce new fruit set relative to irrigated trees. Fruit growth after the delayed bloom caught up with the irrigated treatments so final yield and fruit quality were not affected. During mechanical harvesting, previously drought stressed trees had a higher fruit removal efficiency and less loss of the smaller young fruit than continuously irrigated trees for up to three months. Thus, winter time drought stress can be an effective practice to delay flowering and to avoid young fruit loss during late season mechanical harvesting of 'Valencia' oranges. Fruitlet oleocellosis in late season mechanical harvested trees did not increase fruitlet drop nor alter internal fruit quality.
  • Authors:
    • Bjorneberg, D. L.
    • King, B. A.
    • Tarkalson, D. D.
    • Taberna, J. P.
  • Source: Potato Research
  • Volume: 55
  • Issue: 1
  • Year: 2012
  • Summary: Research studies have evaluated the production of potatoes ( Solanum tuberosum L.) grown in conventional and bed planting configurations. However, intercepted photosynthetically active radiation (PAR) from these planting configurations has not been quantified. A study conducted in 2008 and 2009 quantified and compared the intercepted PAR from three planting configurations (four row conventional ridged-row [4RC], five row bed [5RB], and seven row bed [7RB]), and from different plant spacings of cvs Russet Burbank, Russet Norkotah, and Ranger Russet potatoes under sprinkler irrigation. A second study was conducted in 2007 to evaluate the relationship between PAR and leaf area of Russet Norkotah and Russet Burbank for the three planting configurations. These studies were conducted at the USDA-ARS Northwest Irrigation & Soils Research Lab in Kimberly, ID, on a Portneuf silt loam (coarse-silty mixed mesic Durixerollic Calciorthid). The canopy of Russet Norkotah and Ranger Russet potatoes grown in 5RB and 7RB planting configurations intercepted more PAR during the early vegetative and tuber initiation growth stages compared to the 4RC planting configuration at equal populations in 2008 and 2009 at all measurement dates. The canopy of Russet Burbank intercepted more PAR during the early growth stage in 2008 when planted in the bed planting configurations compared to the 4RC planting configuration, but not on the July 17, 2008 and July 9, 2009 dates. The canopy cover of Russet Burbank potatoes planted in the 4RC planting configuration tended to catch up with the bed planting configurations quicker than the other two cultivars. In general, the quantity of PAR intercepted as affected by planting configuration did not influence total tuber yield and other measured production variables. Cumulative PAR interception 0-72 days after planting (DAP) was increased 35%, 38%, and 32% for the 5RB and 65%, 69%, 23% for the 7RB relative to the 4RC planting configuration for Ranger Russet, Ranger Norkotah, and Russet Burbank, respectively. Cumulative PAR interception for the season was increased 15%, 16%, and 4% for the 5RB and 23%, 23%, 5% for the 7RB relative to the 4RC planting configuration for Ranger Russet, Ranger Norkotah, and Russet Burbank, respectively. The relationship between intercepted PAR and leaf area for Russet Norkotah during the early vegetative and tuber initiation growth stages was significantly different between the three planting configurations, with intercepted PAR at a given leaf area in the order of 7RB>5RB>4RC. For Russet Burbank, the relationship was significantly different for the 5RB and 7RB compared to 4RC planting configuration only, with intercepted PAR at a given leaf area in the order of 7RB=5RB>4RC.
  • Authors:
    • Wise, J. C.
    • van Timmeren, S.
    • Isaacs, R.
  • Source: Pest Management Science
  • Volume: 68
  • Issue: 4
  • Year: 2012
  • Summary: BACKGROUND: Soil application of systemic neonicotinoid insecticides can provide opportunities for long-term control of insect pests in vineyards, with minimal risk of pesticide drift or worker exposure. This study compared the effectiveness of neonicotinoid insecticides applied via irrigation injection on key early-season and mid-season insect pests of vineyards in the eastern United States. RESULTS: On vines trained to grow on drip irrigation, early-season application of imidacloprid, clothianidin, thiamethoxam and dinotefuran provided high levels of control against the potato leafhopper, Empoasca fabae. Protection of vines against Japanese beetle, Popillia japonica, and grape berry moth, Paralobesia viteana, was also observed after mid-season applications. Efficacy was poor in commercial vineyards when treatments were applied to the soil before irrigation or rain, indicating that vines must be grown with an irrigation system for efficient uptake of the insecticide. CONCLUSIONS: In drip-irrigated vineyards, soil-applied neonicotinoids can be used to provide long residual control of either early-season or mid- to late-season foliage pests of vineyards. This approach can reduce the dependence on foliar-applied insecticides, with associated benefits for non-target exposure to workers and natural enemies.
  • Authors:
    • Mullinix, B. G.,Jr.
    • Keeling, J. W.
    • Bordovsky, J. P.
    • Wheeler, T. A.
    • Woodward, J. E.
  • Source: Plant Disease
  • Volume: 96
  • Issue: 7
  • Year: 2012
  • Summary: A field experiment was conducted under center-pivot irrigation in four wedges, with one wedge in continuous cotton (CC) and three wedges in a rotation (ROT) with 2 years cotton and 1 year in sorghum. Three irrigation rates (base = 1.0B, 1.5B, and 0.5B) were applied during 2007 to 2009 on a susceptible (ST) and partially resistant (PR) cultivar. Nitrogen applied during the season was proportional to irrigation rate. In the ROT wedges, 0.5B, 1.0B, and 1.5B irrigation and nitrogen rates averaged 1, 3, and 9% incidence of wilt, respectively. Disease incidence in the CC wedge averaged 6, 18, and 34% wilt incidence for 0.5B, 1.0B, and 1.5B irrigation and nitrogen rates. In the ROT wedges, the ST cultivar returned $143/ha more than the PR cultivars at the 0.5B irrigation and nitrogen rate whereas, at the 1.0B and 1.5B rates, the PR cultivars averaged $121 and $350/ha more than the ST cultivar. There was no significant irrigation and nitrogen or cultivar effect in the CC wedge on net value; however, trends were similar to the ROT wedge. Overall, ROT returned $285/ha more than CC, PR cultivars returned $123/ha more than the ST cultivar, and 1.0B returned $271 and $296/ha more than 0.5B and 1.5B rates, respectively. Microsclerotia density of V. dahliae averaged 2/cm(3) of soil in the ROT wedges and 23/cm(3) of soil in the CC wedge. Crop rotation, avoiding excessive irrigation, and using a partially resistant cultivar all reduced incidence of Verticillium wilt and improved net returns.
  • Authors:
    • Rosen, C. J.
    • Bierman, P. M.
    • Venterea, R. T.
    • Lamb, J. A.
  • Source: Agricultural Systems
  • Volume: 109
  • Year: 2012
  • Summary: A survey was conducted in the spring of 2010 to characterize the use of nitrogen (N) fertilizer on corn ( Zea mays L.) by Minnesota farmers in the 2009 growing season. Detailed information on synthetic N fertilizer management practices was collected from interviews with 1496 farmers distributed across all of the corn growing regions in the state. The total amount of corn they grew represented 6.8% of the ha of corn harvested in Minnesota in 2009. This report summarizes data on: (1) N fertilizer rates, (2) major N sources (excluding manures), (3) application timing of the major N source, (4) use of nitrification inhibitors, additives, and specialty N fertilizer formulations, (5) fertilizer placement and incorporation practices, (6) use of starter fertilizer, split and sidedress applications, and other N sources such as ammonium phosphates, (7) N fertilization of irrigated corn, and (8) use of soil testing as a fertility management tool. Many of the survey results are reported as statewide averages, but where regional differences occurred the data are broken down and presented separately for different parts of the state. This survey provides the most comprehensive set of data on N fertilizer use on corn that has been collected in Minnesota. The information can be used to target research and education programs to improve N management for both production and environmental goals. The statewide average N fertilizer rate was 157 kg N ha -1. Variable rate application was used to apply N by 23% of farmers. About 59% of surveyed farmers applied the majority of their N fertilizer in the spring before planting, 32.5% made their main N application in the fall, and 9% sidedressed the majority of their N after corn emergence. Most farmers used anhydrous ammonia (46%) or urea (45%) as their major source of N fertilizer, while 6.5% used a liquid N formulation as their primary N source. Soil testing was used as a fertility management tool on 84% of the surveyed fields in the last 5 years. Overall results indicate that N fertilizer use by Minnesota corn farmers is generally consistent with University of Minnesota Extension N management guidelines. Fertilizer N use could probably be improved by taking adequate N credit for previous soybean crops. In the South Central region of the state, fertilizer N recovery could potentially be improved by increased use of nitrification inhibitors with fall-applied anhydrous ammonia or by delaying anhydrous ammonia application until spring.
  • Authors:
    • Vimont, D. J.
    • Vavrus, S.
    • Notaro, M.
    • Lorenz, D.
    • Williams, J. W.
    • Veloz, S.
  • Source: CLIMATIC CHANGE
  • Volume: 112
  • Issue: 3-4
  • Year: 2012
  • Summary: There is a deep disconnect between scientific and public concern about climate change. One reason is that global climate change is a fairly abstract concept with little perceived relevance, so a key challenge is to translate climate-change projections into locally concrete examples of potential impacts. Here we use climate analog analyses as an alternative method for identifying and communicating climate-change impacts. Our analysis uses multiple downscaled general circulation models for the state of Wisconsin, at 0.1 decimal degree resolution, and identifies contemporary locations in North America that are the most similar to the projected future climates for Wisconsin. We assess the uncertainties inherent in climate-change projections among greenhouse gas emission scenarios, time windows (mid-21st century vs. late 21st-century) and different combinations of climate variables. For all future scenarios and simulations, contemporary climatic analogs within North America were found for Wisconsin's future climate. Closest analogs are primarily 200-500 km to the south-southwest of their Wisconsin reference location. Temperature has the largest effect on choice of climatic analog, but precipitation is the greatest source of uncertainty. Under the higher-end emission scenarios, the contemporary climatic analogs for Wisconsin's end-21st-century climates are almost entirely outside the state. Climate-analog analyses offer a place-based means of assessing climate impacts that is complementary to the species-based approaches of species distributional models, and carries no assumptions about the characterization and conservatism of species niches. The analog method is simple and flexible, and can be readily extended to other regions and other environmental variables.
  • Authors:
    • Higginbotham, R. W.
    • Jones, S. S.
    • Carter, A. H.
  • Source: Sustainability
  • Volume: 3
  • Issue: 8
  • Year: 2011
  • Summary: In Washington, over fifty percent of the wheat produced under rainfed conditions receives less than 300 mm of annual precipitation. Hence, a winter wheat-summer fallow cropping system has been adopted to obtain adequate moisture for winter wheat production. Current tilled fallow systems are exposed to significant soil degradation from wind and water erosion. As a result, late-planted no-till fallow systems are being evaluated to mitigate erosion concerns. The objective of this study was to evaluate current cultivars under late-planted no-till fallow systems to identify whether current breeding schemes in tilled fallow systems could select productive cultivars in late-planted no-till fallow systems. Thirty cultivars were planted in a split-plot design with fallow type as the main plot and genotype as the sub-plot. Fallow types evaluated were a tilled fallow system and a late planted no-till fallow system. Data were collected on heading date, plant height, grain volume weight, grain yield, and grain protein content. Analysis of variance was conducted on data across locations. Results were significant for all traits except for grain protein content. The late-planted no-till fallow system headed 16 days later was 5 cm shorter, yielded 36% less, and had a grain volume weight 3% less than the tilled fallow system. The lower yield and grain volume weight potential is hypothesized to be due to the 16 day delay in heading date leading to warmer temperatures during grain fill and a shorter duration. In order to breed wheat to be highly productive under a late-planted no-till fallow system, directly selecting in this system for early spring growth and earlier heading dates will be essential.
  • Authors:
    • Kondratieff, B. C.
    • Booher, M. R.
    • Goldhamer, D. A.
    • Hurisso, T. T.
    • Davis, J. G.
    • Brummer, J. E.
    • Stromberger, M. E.
    • Stonaker, F. H.
  • Source: Applied Soil Ecology
  • Volume: 48
  • Issue: 2
  • Year: 2011
  • Summary: We evaluated the effects of soil amendments on earthworm communities in organic annual forage and perennial pasture systems in northern Colorado. In the annual forage study (1) an annual warm season grass teff ( Eragrostis tef) and (2) bare fallow were main plot treatments and received one of three soil amendments: (1) composted dairy manure (CDM), (2) raw dairy manure (RDM), and (3) no amendment as control. For the perennial pasture study, CDM was topdressed onto a grass mixture consisting of orchardgrass, smooth and meadow bromegrass at rates ranging from 0 to 44.8 Mg ha -1. At both sites, earthworm and soil samples were collected in July 2009. The earthworms identified from both systems were composed of endogeic species Aporrectodea rosea (Savigny), A. tuberculata (Eisen), and A. turgida (Eisen), the first being found only in the perennial pasture. In the annual forage study, earthworm total abundance did not differ between teff and bare fallow treatments. However, within bare fallow treatment, earthworm total abundance was significantly affected by soil amendment, with CDM averaging approximately 1.4 and 5.4 times greater earthworm total abundance than RDM and the control, respectively. Earthworm total abundance was found to be positively correlated with soil Cu ( R=0.51, P=0.03) and K ( R=0.58, P=0.01). In the perennial pasture, earthworm total abundance tended to increase with an increase in the CDM rate to 33.6 Mg ha -1. However, no further increase was observed when the CDM rate was increased to 44.8 Mg ha -1. At this site, earthworm total abundance was negatively correlated with EC ( R=-0.37, P=0.02). Our results suggest that high quality (low C/N ratio) dairy manure is important for maintaining a high earthworm population. Larger CDM application rates appear to discourage earthworm populations probably due to salinity stress. Further study is necessary to elucidate the exact effects of manure quality and quantity on earthworm populations in annual forages and perennial pastures.
  • Authors:
    • Beasley, J. P.,Jr.
    • Tubbs, R. S.
    • Lee, R. D.
    • Grey, T. L.
    • Jackson, J. L.
  • Source: Peanut Science
  • Volume: 38
  • Issue: 1
  • Year: 2011
  • Summary: Most peanut ( Arahcis hypogaea L.) production occurs under highly intensive conventional tillage systems. With recent volatility in input prices, reducing tillage trips is a viable way of reducing production costs. However, growers can experience yield loss when switching from conventional tillage to strip-tillage in peanut on certain soil types due to the lack of an elevated bed at harvest time. Studies were conducted to compare standard strip-till with strip-till on two-row raised beds as well as rip and beds prepared in the fall. Comparisons were made on a coarse textured soil at Tifton, GA and a fine textured soil at Plains, GA. The three bed types, with and without wheat cover, were evaluated over two years at both locations. No effects of cover or interactions with bed type were present. At Plains, the rip and bed and raised bed reduced digging losses by 62 and 47%, respectively. Soil compaction within the harvest depth was reduced by 3.3 and 4.7 times by the raised bed and rip and bed, respectively compared to flat strip-till. The rip and bed increased peanut yield by 465 kg ha -1 over flat bed. At Tifton, no significant differences in yield or digging losses occurred between tillage methods. Soil compaction in the harvest depth was reduced by 1.9 and 2.5 times by raised bed and rip and bed, respectively on this coarse soil type. Reduced compaction and digging losses along with increased yield suggest bedding is more important on finer textured soils.