• Authors:
    • Vanotti, M. B.
    • Matheny, T. A.
    • Stone, K. C.
    • Hunt, P. G.
    • Szogi, A. A.
    • Busscher, W. J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 22
  • Year: 2011
  • Summary: The wastewater from swine production facilities has been typically managed by treatment in anaerobic lagoons followed by land application. However, there have been considerable advances in superior treatment technologies. Wastewater from one of these technologies was effective for subsurface drip irrigation of bermudagrass. The objectives of this experiment were to assess accumulation of soil nitrogen and carbon along with grain yield, dry-matter accumulation, and plant nitrogen accumulation of soybean [ Glycine max (L) Merr., cv.] and wheat [ Triticum aestivum (L), cv.] when supplementally irrigated with treated swine effluent via subsurface drip irrigation (SDI). The soil series was Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults). Its low unsaturated hydraulic conductivity of 0.00170.0023 mm h -1 caused problems with water movement to either the soil surface or laterally to adjoining soybean and wheat roots. This condition contributed to complete crop failure in soybean in 2 years and generally poor yields of wheat. In a good rainfall year, the soybean yield was somewhat satisfactory and benefited from the supplemental irrigation. In that year, nonirrigated and irrigated soybean mean yields were 1.55 versus 1.98 Mg ha -1, respectively. The mean yield of wheat was only 1.06 Mg ha -1, and it was not affected by irrigation. The means for soil nitrogen and carbon in the 0- to 15-cm depth were 414 and 5,679 mg kg -1, respectively, and they were not affected by the water treatments. Thus, neither soil conditions nor soybean/wheat production were greatly enhanced by the SDI system.
  • Authors:
    • Walter-Shea, E. A.
    • Singh, R. K.
    • Irmak, A.
    • Verma, S. B.
    • Suyker, A. E.
  • Source: Transactions of the American Society of Agricultural and Biological Engineers and Papers in Natural Resources. Paper 334.
  • Volume: 54
  • Issue: 1
  • Year: 2011
  • Summary: We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (R n) ratio (G/R n) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/R n ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/R n ratio decreased with crop growth and development. The G/R n ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of R n for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m -2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.
  • Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
    • Jabro, J. D.
    • Evans, R. G.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 18
  • Year: 2011
  • Summary: We evaluated the effect of no tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density (BD), gravimetric moisture content (MC), and saturated hydraulic conductivity (Ks) during the fallow phase of a spring wheat-fallow rotation. The study was conducted on two soils mapped as Williams loam at the Froid and Sidney sites. Soil measurements were made on 19 May, 23 June, and 4 August 2005 at the Froid site and on 6 June and 8 July 2005 at the Sidney site. Tillage had no effect on either soil properties except on the PR at Sidney. However, soil PR, MC, and BD varied significantly with depth regardless of tillage and location. Further, soil PR and MC varied with the date of sampling at both locations, and PR generally increased with decreased MC at all soil depths. Soil Ks was slightly influenced by tillage at both locations.
  • Authors:
    • Esker, P. D.
    • Jirak-Peterson, J. C.
  • Source: Plant Disease
  • Volume: 95
  • Issue: 5
  • Year: 2011
  • Summary: Corn anthracnose (Colletotrichum graminicola) is an important disease of field coni (Zea mays). Two phases, leaf blight and stalk rot, can reduce yield through either premature leaf senescence or reduced grain harvest due to stalk lodging. Corn residue is an important source of primary inoculum and is increased through cultural practices such as no-tillage and continuous corn cropping, which are common practices in Wisconsin. Field studies conducted at the Arlington Agricultural Research Station (ARS) and the West Madison ARS showed that the incidence and severity of anthracnose leaf blight were higher in continuous-corn crop rotations than in soybean corn rotations (91% higher incidence, 24 to 78% higher severity). Anthracnose stalk rot was marginally affected by tillage in 2008 (P = 0.09), with higher incidence in chisel-plowed treatments. There was a positive association between spring residue cover and anthracnose leaf blight but no association was found between residue and stalk rot. No association was found between anthracnose leaf blight and stalk rot. There was a negative association between anthracnose leaf blight and yield but not between anthracnose stalk rot and yield. Managing residue levels through crop rotation would help to reduce anthracnose leaf blight but further work is needed to elucidate factors that lead to stalk lodging prior to harvest.
  • Authors:
    • Verma, S. B.
    • Vanegas, D. X.
    • Xiao, X. M.
    • Kalfas, J. L.
    • Suyker, A. E.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO 2 between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation Photosynthesis Model (VPM) and satellite images from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate seasonal dynamics and interannual variation of GPP during 2001-2005 at five maize cropland sites located in Nebraska and Minnesota of the U.S.A. These sites have different crop rotation systems (continuously maize vs. maize and soybean rotated annually) and different water management practices (irrigation vs. rain-fed). The VPM is based on the concept of light absorption by chlorophyll and is driven by the Enhanced Vegetation Index (EVI) and the Land Surface Water Index (LSWI), photosynthetically active radiation (PAR), and air temperature. The seasonal dynamics of GPP predicted by the VPM agreed well with GPP estimates from eddy covariance flux tower data over the period of 2001-2005. These simulation results clearly demonstrate the potential of the VPM to scale-up GPP estimation of maize cropland, which is relevant to food, biofuel, and feedstock production, as well as food and energy security.
  • Authors:
    • Halloran, J. M.
    • Olanya, O. M.
    • Griffin, T. S.
    • Honeycutt, C. W.
    • Larkin, R. P.
    • He, Z.
  • Source: Phytopathology
  • Volume: 101
  • Issue: 1
  • Year: 2011
  • Summary: Four different potato cropping systems, designed to address specific management goals of soil conservation, soil improvement, disease suppression, and a status quo standard rotation control, were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. The status quo system (SQ) consisted of barley under-seeded with red clover followed by potato (2-year). The soil-conserving system (SC) featured an additional year of forage grass and reduced tillage (3-year, barley/timothy-timothy-potato). The soil-improving system (SI) added yearly compost amendments to the SC rotation, and the disease-suppressive system (DS) featured diverse crops with known disease-suppressive capability (3-year, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared with a continuous potato control (PP) and evaluated under both irrigated and nonirrigated conditions. Data collected over three potato seasons following full rotation cycles demonstrated that all rotations reduced stem canker (10 to 50%) relative to PP. The SQ, SC, and DS systems reduced black scurf (18 to 58%) relative to PP; ST reduced scurf under nonirri2ated but not irrigated conditions; and scurf was lower in DS than all other systems. The SQ. SC, and DS systems also reduced common scab (15 to 45%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab but also resulted in higher yields for most rotations. SI produced the highest yields under nonirrigated conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and fatty acid methyl-ester (FAME) profiles. SI tended to increase soil moisture, microbial populations, and activity, as well result in higher proportions of monounsaturated FAMEs and the FAME biomarker for mycorrhizae (16:1 omega 6c) relative to most other rotations. DS resulted in moderate microbial populations and activity but higher substrate richness and diversity in substrate utilization profiles. DS also resulted in relatively higher proportions of FAME biomarkers for fungi (18:2 omega 6c), actinomycetes, and gram-positive bacteria than most other systems, whereas PP resulted in the lowest microbial populations and activity; substrate richness and diversity; proportions of monounsaturated and polyunsaturated FAME classes; and fungal, mycorrhizae, and actinomycete FAME biomarkers of all cropping systems. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches will need to balance these factors to achieve sustainable production and disease management.
  • Authors:
    • Brandenburg, R. L.
    • Shew, B. B.
    • Wilkerson, G. G.
    • Jordan, D. L.
    • Lassiter, B. R.
  • Source: Weed Technology
  • Volume: 25
  • Issue: 4
  • Year: 2011
  • Summary: Experiments were conducted in North Carolina during 2005, 2006, and 2007 to determine peanut and weed response when peanut was planted in strip tillage after desiccation of cereal rye, Italian ryegrass, oats, triticale, wheat, and native vegetation by glyphosate and paraquat before planting with three in-season herbicide programs. Control of common ragweed and yellow nutsedge did not differ among cover crop treatments when compared within a specific herbicide program. Applying dimethenamid or S-metolachlor plus diclosulam PRE followed by imazapic POST was more effective than a chloroacetamide herbicide PRE followed by acifluorfen, bentazon, and paraquat POST. Incidence of spotted wilt in peanut (caused by a Tospovirus) did not differ when comparing cover crop treatments, regardless of herbicide program. Peanut yield increased in all 3 yr when herbicides were applied POST, compared with clethodim only. Peanut yield was not affected by cover crop treatment. Response to cover crop treatments was comparable, suggesting that growers can select cereal rye, Italian ryegrass, oats, or triticale as an alternative to wheat as a cover crop in peanut systems without experiencing differences associated with in-season weed management.
  • Authors:
    • Mengel, D. B.
    • Olson, B. L.
    • Martin, K. L.
    • Diaz, D. A. R.
    • Liesch, A. M.
    • Roozeboom, K. L.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Soybean [ Glycine max (L.) Merr.] production has increased by more than 55,000 ha in the last 25 yr in the western third of Kansas, a region with soils that can be prone to Fe chlorosis. The objective of this study was to evaluate the relative effectiveness of varietal selection, seed-applied Fe fertilizer, and foliar Fe application to reduce the incidence of Fe chlorosis under irrigated soybean production. Seven locations with a history of Fe deficiency in soybeans were selected. The study consisted of a factorial design with three foliar treatments (two chelated Fe fertilizer forms and no foliar), two seed-applied Fe fertilizer treatments (with and without chelated Fe fertilizer), and two different varieties (a nontolerant and tolerant commercial variety). Plant population, chlorophyll meter (CM) readings (V3 and V6 growth stage), plant height at maturity, and grain yield were measured. Foliar Fe application did not affect any plant parameter except for CM reading and grain yield at one location. However, the use of seed-applied chelated Fe fertilizer significantly increased CM readings at the V3 and V6 growth stages, plant height at maturity, and grain yield across all locations. Given soil conditions conducive to the development of severe iron chlorosis, seed-applied chelated Fe fertilizer increased yields by approximately 55% for both varieties. Chlorosis quantified as CM readings at V3 to V6 growth stage may not be correlated to the yield potential of a variety in all environments. This suggests that producers should choose the best varieties primarily based on yield potential if supplemental seed-applied Fe fertilizer will be used.
  • Authors:
    • Nzokou, P.
    • Wilson, A. R.
    • Lin, Y.
  • Source: HortScience
  • Volume: 46
  • Issue: 3
  • Year: 2011
  • Summary: High rates of inorganic fertilizers are used in conventional intensive production systems such as Abies fraseri (fraser fir) cropping systems for Christmas trees. Groundcovers can be used as green mulches, help reduce the use of farm chemicals, and provide several environmental benefits. We investigated the performance of a low-input cropping system by combining two legume cover crops [Dutch white clover (Trifolium repens) and alfalfa (Medicago sativa)] in combination with low rates of inorganic fertilizers as a step toward a more sustainable production system. The randomized block design comprised one cover crop and one of three applications of reduced rate inorganic fertilizer (75%, 50%, and 25% of the recommended rate). A conventional system using herbicides for weed control and the 100% rate of inorganic fertilizer was used as a control. Parameters measured included tree morphology, foliar nitrogen concentration, soil mineral nitrogen, and nitrate-N leaching below the root zone. A significant positive growth response (height and diameter) was obtained in all alfalfa-based cropping systems. This was accompanied by foliar nutrient concentrations similar to conventional plots and a reduction in nitrate-N leaching. However, in white clover-based cropping systems, the growth response was reduced (both height and diameter), suggesting competition for soil resources. In addition, the total nitrate-N leaching was higher in this system, suggesting an imbalance between mineral nitrogen availability and use in white clover-based cropping systems. We conclude that if the potential competition between cover crops and trees can be properly managed, legume cover crops can be effectively used to make intensive production tree-based systems more sustainable. Further studies related to mineralization and macronutrient flows are needed before any definite recommendation can be made about the use of these systems in large-scale production systems.
  • Authors:
    • Galusha, T. D.
    • Jackson, D. S.
    • Mason, S. C.
    • Griess, J. K.
    • Pedersen, J. F.
    • Yaseen, M.
  • Source: Crop Science
  • Volume: 51
  • Issue: 4
  • Year: 2011
  • Summary: Grain processors would benefit from information about the production environment and the influences of the sorghum [ Sorghum bicolor (L.) Moench] hybrid on food-grade flour properties. The objective of this study was to determine the effects of environment and hybrid on rapid-visco-analysis (RVA) flour properties of commercially available food-grade sorghum. A randomized complete block experiment was planted in 12 environments, which included the 2004 and 2005 growing seasons and irrigated and dryland water regimes in eastern, central, and west central Nebraska, and a dryland, low-N environment in eastern Nebraska. The environment accounted for 71-85% of the total variation in RVA parameters, while the hybrid accounted for 11-23% and the environment-by-hybrid interaction, 1-3%. Unfortunately, the results of this experiment suggest that it is difficult to predict the effect that environment will have on resulting sorghum-flour parameters. Although of secondary importance in terms of total variation in sorghum-flour RVA properties, the choice of hybrid predictably and significantly contributes to sorghum-starch viscosity properties. Food-grade hybrids were grouped based on viscosity properties into those best suited for dry-mill and alkaline-cooked products (Asgrow Orbit; Sorghum Partners NK1486) and those best suited for porridge, consumable alcohol, and ethanol production (Kelly Green Seeds KG6902; NC+ Hybrids 7W92; Asgrow Eclipse; and Fontanelle W-1000). These results were consistent with those previously reported for grain density.