• Authors:
    • Ngouajio, M.
    • Wang, G.
  • Source: Hortscience
  • Volume: 43
  • Issue: 6
  • Year: 2008
  • Summary: The effects of two cover crops [cereal rye ( Secale cereale L.) and oat ( Avena sativa L.)], four tillage systems [no tillage (NT), strip tillage (ST), conventional tillage with cover crops incorporated (CTC), and conventional tillage without cover crop (CTN)], and three pre-emergence herbicide rates (full rate, half rate, and no herbicide) on pickling cucumber ( Cucumis sativus L.) growth and production, weed populations, and the incidence of pythium fruit rot were studied. Weed infestations, cucumber establishment, and cucumber leaf chlorophyll content were similar between the rye and oat treatments. However, the oat treatment had higher cucumber fruit number and weight and a lower percentage of cucumber fruit infected with Pythium spp. compared with the rye treatment. The NT and CTC systems reduced cucumber stand and leaf chlorophyll content, but had equivalent cucumber fruit number and weight compared with CTN. The NT and ST had lower weed biomass and weed density than CTN and CTC. The NT also reduced the percentage of cucumber fruit affected with pythium compared with CTN and CTC. Reducing the pre-emergence herbicide rate by half did not affect weed control or cucumber fruit yield compared with the full rate. However, weeds escaping herbicide application were larger in the half-rate treatment. The experiments indicate that with the integration of cover crops and conservation tillage, it is possible to maintain cucumber yield while reducing both herbicide inputs (by 50%) and the incidence of fruit rot caused by Pythium spp. (by 32% to 60%).
  • Authors:
    • Leser, J. F.
    • Wheeler, T. A.
    • Keeling, J. W.
    • Mullinix, B.
  • Source: JOURNAL OF NEMATOLOGY
  • Volume: 40
  • Issue: 2
  • Year: 2008
  • Summary: Terminated small grain cover crops are valuable in light textured soils to reduce wind and rain erosion and for protection of young cotton seedlings. A three-year study was conducted to determine the impact of terminated small grain winter cover crops, which are hosts for Meloidogyne incognita, on cotton yield, root galling and nematode midseason population density. The small plot test consisted of the cover treatment as the main plots (winter fallow, oats, rye and wheat) and rate of aldicarb applied in-furrow at-plant (0, 0.59 and 0.84 kg a.i./ha) as subplots in a split-plot design with eight replications, arranged in a randomized complete block design. Roots of 10 cotton plants per plot were examined at approximately 35 days after planting. Root galling was affected by aldicarb rate (9.1, 3.8 and 3.4 galls/root system for 0, 0.59 and 0.84 kg aldicarb/ha), but not by cover crop. Soil samples were collected in mid-July and assayed for nematodes. The winter fallow plots had a lower density of M. incognita second-stage juveniles (J2) (transformed to Log 10 (J2+1)/500 cm 3 soil) than any of the cover crops (0.88, 1.58, 1.67 and 1.75 Log 10(J2+1)/500 cm 3 soil for winter fallow, oats, rye and wheat, respectively). There were also fewer M. incognita eggs at midseason in the winter fallow (3,512, 7,953, 8,262 and 11,392 eggs/500 cm 3 soil for winter fallow, oats, rye and wheat, respectively). Yield (kg lint per ha) was increased by application of aldicarb (1,544, 1,710 and 1,697 for 0, 0.59 and 0.84 kg aldicarb/ha), but not by any cover crop treatments. These results were consistent over three years. The soil temperature at 15 cm depth, from when soils reached 18°C to termination of the grass cover crop, averaged 9,588, 7,274 and 1,639 centigrade hours (with a minimum threshold of 10°C), in 2005, 2006 and 2007, respectively. Under these conditions, potential reproduction of M. incognita on the cover crop did not result in a yield penalty.
  • Authors:
    • Rossi, R.
    • Harsh, J.
    • Huggins, D.
    • Koenig, R.
    • Brown, T.
  • Source: Soil Science Society of America Journal
  • Volume: 72
  • Issue: 3
  • Year: 2008
  • Summary: Soil acidification threatens dryland crop production in the inland Pacific Northwest. Our objective was to assess the efficacy of lime to lower soil acidity, alter Al chemistry, and increase crop yield in a direct-sown system in Washington, USA. Treatments of subsurface banded fertilizer (120-168 kg N ha -1 year -1) alone or with subsurface banded lime (224 kg ha -1 year -1), or a one-time broadcast application of lime (7000 kg ha -1) or elemental S (1000 kg ha -1) were initiated in spring 2002. Grain yield was measured annually from 2002 to 2005 in a spring barley ( Hordeum vulgare)-spring wheat ( Triticum aestivum)-winter wheat rotation. Soil was sampled in spring 2004 to assess pH and model Al speciation. Low pH was evident at the depth of fertilizer placement (5-10 cm). Broadcast lime increased pH in the surface 15 cm, although reductions in Al 3+ activity ((Al 3+)) occurred only in the 0- to 5-cm layer. Relative to banded N, there was no increase in pH at the 5- to 10-cm depth where banded lime was placed. At the 0- to 5-cm depth, lower pHs were observed with broadcast S (4.6) compared with the banded N control (5.1) or banded lime (5.0). There was no effect of treatment on yield. Modelling suggests that soluble Al is dominated by organic matter-Al complexes (fulvic acid, FA; FA 2Al + and FA 2AlOH 0). Solid- and solution-phase organic complexes may control (Al 3+) at pH
  • Authors:
    • Rhinhart, K.
    • Kling, J.
    • Hayes, P.
    • Corey, A.
    • Budde, A.
    • Petrie, S.
    • Castro, A.
  • Source: Crop Management
  • Issue: November
  • Year: 2008
  • Summary: Winter malting barley ( Hordeum vulgare L.) is a potential alternative crop for the dryland region of the Pacific Northwest. Nitrogen fertilization can increase grain yield but may also increase lodging and grain protein and reduce test weight. The objectives of this research were to determine the effect of N application rate and timing on grain yield and quality of winter feed and malting barley varieties. Field trials were conducted at Pendleton, OR (17 inches annual precipitation) and Moro, OR (12 inches annual precipitation). Nitrogen was applied at 0, 50, 100, or 150 lb N per acre in the fall and at 0 or 50 lb N per acre in the spring at Pendleton and at 0, 30, 60, or 90 lb N per acre in the fall and at 0 or 30 lb N per acre in the spring at Moro. Nitrogen fertilization increased grain yields at Pendleton to a maximum of 5,800 lb/acre in 2001 and 5,200 lb/acre in 2002 and at Moro to a maximum of 3,000 lb/acre. Nitrogen fertilization increased grain protein and reduced test weights. Yields of the advanced lines of malting barley were about 90% of the yields of feed type barley varieties. Spring N applications did not increase grain yield or protein more than fall N applications.
  • Authors:
    • Hons, F.
    • Wright, A.
    • Dou, F.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 39
  • Issue: 5/6
  • Year: 2008
  • Summary: Distribution of dissolved (DOC) and soil organic carbon (SOC) with depth may indicate soil and crop-management effects on subsurface soil C sequestration. The objectives of this study were to investigate impacts of conventional tillage (CT), no tillage (NT), and cropping sequence on the depth distribution of DOC, SOC, and total nitrogen (N) for a silty clay loam soil after 20 years of continuous sorghum cropping. Conventional tillage consisted of disking, chiseling, ridging, and residue incorporation into soil, while residues remained on the soil surface for NT. Soil was sampled from six depth intervals ranging from 0 to 105 cm. Tillage effects on DOC and total N were primarily observed at 0-5 cm, whereas cropping sequence effects were observed to 55 cm. Soil organic carbon (C) was higher under NT than CT at 0-5 cm but higher under CT for subsurface soils. Dissolved organic C, SOC, and total N were 37, 36, and 66%, respectively, greater under NT than CT at 0-5 cm, and 171, 659, and 837% greater at 0-5 than 80-105 cm. The DOC decreased with each depth increment and averaged 18% higher under a sorghum-wheat-soybean rotation than a continuous sorghum monoculture. Both SOC and total N were higher for sorghum-wheat-soybean than continuous sorghum from 0-55 cm. Conventional tillage increased SOC and DOC in subsurface soils for intensive crop rotations, indicating that assessment of C in subsurface soils may be important for determining effects of tillage practices and crop rotations on soil C sequestration.
  • Authors:
    • Sweeney, D.
    • Kelley, K.
  • Source: Crop Management
  • Issue: November
  • Year: 2008
  • Summary: Field studies were conducted from 1999 through 2004 in southeastern Kansas to evaluate the influence of tillage method [conventional (CT) and no-till (NT)], row spacing-population system (7.5-, 15-, and 30-inch rows planted at 225,000, 175,000, and 125,000 seeds/acre, respectively), and glyphosate application timing on soybean [ Glycine max (L.) Merr.] yield, weed control, and net economic returns. Herbicide treatments were: (i) preplant residual (pendimethalin) followed by glyphosate at 3 weeks after planting (WAP); (ii) glyphosate at 3 WAP; (iii) sequential glyphosate at 3 and 5 WAP; and (iv) glyphosate at 8 WAP. Soybean followed grain sorghum [ Sorghum bicolor (L.) Moench] in a 2-year rotation. Tillage method influenced yield very little. Narrower row spacing (7.5- and 15-inch) increased soybean yields 2 to 4 bu/acre in high-yielding environments compared to 30-inch rows and also provided greater weed control. Glyphosate applied sequentially (3 and 5 WAP) provided the highest weed control, but a single glyphosate application 3 WAP often produced the greatest net return, regardless of tillage or row spacing system. The results suggest that the adoption of NT planting will likely increase soybean net returns to a greater extent than reducing row spacing in the eastern Great Plains.
  • Authors:
    • Pierzynski, G.
    • Tuppad, P.
    • Janssen, K.
    • Mankin, K.
    • Maski, D.
  • Source: Journal of Soil and Water Conservation
  • Volume: 63
  • Issue: 4
  • Year: 2008
  • Summary: Cropland best management practice recommendations often combine improvements to both tillage and fertilizer application practices to reduce sediment losses with surface runoff. This study evaluated the impact of conventional-till and no-till management practices with surface or deep-banded fertilizer application in sorghum-soybean rotation on runoff and sediment-yield predictions using the Soil and Water Assessment Tool (SWAT) model. The model was calibrated using USDA Natural Resources Conservation Service runoff curve number for antecedent moisture condition II (CN II), saturated hydraulic conductivity, and available water capacity parameters for runoff and USLE cropping factor ( Cmin.) for sediment-yield predictions for three field plots (0.39 to 1.46 ha [0.96 to 3.6 ac]) with different combinations of practices and validated for three field plots (0.40 to 0.56 ha [1.0 to 1.4 ac]) over a period of 2000 to 2004. Surface runoff calibration required CN II values greater than the recommended baseline values. No-till treatments required slightly greater curve number values than the till treatment, and this difference was similar to that associated with increasing the soil hydrologic group by one classification. Generally the model underpredicted the sediment yield for all management practices. Baseline Cmin values were adequate for treatments with soil disturbance, either by tillage or fertilizer deep-banding, but best-fit Cmin values for field conditions without soil disturbance (no-till with surface-broadcast fertilizer) were 2.5 to 3 times greater than baseline values. These results indicate current model limitations in modeling undisturbed (no-till) field management conditions, and caution that models calibrated for fields or watersheds predominated by tilled soil conditions may not function equally well in testing management scenarios without tillage.
  • Authors:
    • Whitmore, J.
    • Chen, X.
    • Jackson, E.
    • Erickson, C.
    • Windes, J.
    • Wesenberg, D.
    • Evans, C.
    • Obert, D.
  • Source: Journal of Plant Registrations
  • Volume: 2
  • Issue: 2
  • Year: 2008
  • Summary: 'Lenetah' (Reg. No. CV-338, PI 652440) two-rowed spring feed barley ( Hordeum vulgare L.) was developed by the Agricultural Research Service, Aberdeen, ID, in cooperation with the Idaho Agricultural Experimental Station and released in December 2007. Lenetah was selected from the cross 94Ab12981/91Ab3148. 94Ab12981 has the pedigree 85Ab2323/'Camas'. 85Ab2323 has the pedigree 79Ab19042/'Crystal'. 79Ab19042 is a selection from the cross 'Klages'/'Hector'. Camas is a selection from the cross ND5976/ND7159. ND5976 has the pedigree 'Maris Concord'/Klages//ND2679-4 and ND7159 has the pedigree Klages/ND1244/3/ND2685/ND1156//Hector. 91Ab3148 has the pedigree 'Gallatin'/'Targhee'//'Bowman'. Lenetah was selected as an F 5:6 line in 2001 and given the experimental designation 01Ab11107. It was released due to its superior yield and test weight compared to 'Baronesse', the most widely grown feed barley in Idaho and Montana. The yield advantage over Baronesse is especially pronounced in northern Idaho and eastern Washington and under dryland conditions.
  • Authors:
    • Stevens, W.
    • Jabro, J.
    • Sainju, U.
  • Source: Journal of Environmental Quality
  • Volume: 37
  • Issue: 1
  • Year: 2008
  • Summary: Management practices can influence soil CO 2 emission and C content in cropland, which can effect global warming. We examined the effects of combinations of irrigation, tillage, cropping systems, and N fertilization on soil CO 2 flux, temperature, water, and C content at the 0- to 20-cm depth from May to November 2005 at two sites in the northern Great Plains. Treatments were two irrigation systems (irrigated vs. non-irrigated) and six management practices that contained tilled and no-tilled malt barley ( Hordeum vulgaris L.) with 0 to 134 kg N ha -1, no-tilled pea ( Pisum sativum L.), and a conservation reserve program (CRP) planting applied in Lihen sandy loam (sandy, mixed, frigid, Entic Haplustolls) in western North Dakota. In eastern Montana, treatments were no-tilled malt barley with 78 kg N ha -1, no-tilled rye ( Secale cereale L.), no-tilled Austrian winter pea, no-tilled fallow, and tilled fallow applied in dryland Williams loam (fine-loamy, mixed Typic Argiborolls). Irrigation increased CO 2 flux by 13% compared with non-irrigation by increasing soil water content in North Dakota. Tillage increased CO 2 flux by 62 to 118% compared with no-tillage at both places. The flux was 1.5- to 2.5-fold greater with tilled than with non-tilled treatments following heavy rain or irrigation in North Dakota and 1.5- to 2.0-fold greater with crops than with fallow following substantial rain in Montana. Nitrogen fertilization increased CO 2 flux by 14% compared with no N fertilization in North Dakota and cropping increased the flux by 79% compared with fallow in no-till and 0 kg N ha -1 in Montana. The CO 2 flux in undisturbed CRP was similar to that in no-tilled crops. Although soil C content was not altered, management practices influenced CO 2 flux within a short period due to changes in soil temperature, water, and nutrient contents. Regardless of irrigation, CO 2 flux can be reduced from croplands to a level similar to that in CRP planting using no-tilled crops with or without N fertilization compared with other management practices.
  • Authors:
    • Lawrence, R.
    • Jones, C.
    • Weist, D.
    • Schulthess, U.
    • Christensen, N.
  • Source: Proceedings of the 9th International Conference on Precision Agriculture, Denver, Colorado, USA, 20-23 July, 2008
  • Year: 2008
  • Summary: RapidEye's five satellites to be launched in the summer of 2008 will make it possible to regularly monitor the N-status of crops from space. The sensors on board of each satellite are equipped with five broad bands: blue, green, red, rededge, and NIR. This opens new avenues for red-edge based algorithms to predict the N-status of cereals. In a study conducted in Montana in 2007, we obtained the best results to predict tissue N content (TNC) of irrigated spring wheat and barley, as well as dryland barley from the following algorithm, based on light reflectance (R) of the canopy in the red, red-edge, and NIR bands: ( TNC= RNIR - Rred-edge )/( RNIR -s* Rred ) where s stands for slope of the soil line, i.e. the separately measured bare soil reflectance of the NIR band divided by the red band. Red-edge band based algorithms will open new avenues to optimize in-season N management of cereals, and for monitoring and verifying the efficacy of N fertilization.