• Authors:
    • Garcia, J.
    • Drijber, R.
    • Franti, T.
    • Mamo, M.
    • Wortmann, C.
    • Quincke, J.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Continuous no-till (NT) has numerous benefits, including improved soil aggregate stability in the surface soil and increased rate of water infiltration, but accumulation of soil P at the soil surface with NT can increase P concentration in runoff. We hypothesized that occasional one-time tillage of NT land, conducted once in 10 or more years, can reduce P runoff and improve crop yields without reducing soil aggregation or increasing runoff. Research was conducted in long-term NT fields under rainfed corn [ Zea mays (L.)] or sorghum [ Sorghum bicolor (L.) Moench.] rotated with soybeans [ Glycine max (L.) Merr.] at two locations in eastern Nebraska. Tillage treatments were applied in the spring or fall and included continuous NT, tandem disk (disk), chisel with 10-cm-wide twisted shanks, moldboard plow (MP), and mini-moldboard plow (miniMP). Subplots had either 0 or 87.4 kg P ha -1 applied as composted feedlot manure before tillage. Yield and yield components were measured for 2 and 3 yr after the spring and fall one-time tillage, respectively. In Year 2 or 3 after tillage, soil sorptivity, field-saturated infiltration rate, runoff volume, runoff P loss, and soil aggregate stability were determined. Yield was not affected by the tillage * compost interaction, but was increased by compost application at one location and sorghum yield was affected by tillage treatments at the second location. Grain yield was never significantly more or less with one-time tillage as compared with NT. Soil aggregate stability was not affected by tillage treatments. Sorptivity and infiltration were increased with MP tillage compared with NT at one location but reduced at the other. One-time MP tillage reduced dissolved P loss at both locations and total phosphorus (TP) loss at one location. The benefit of one-time MP tillage in terms of reduced dissolved reactive P loss in runoff was positive with no negative effect on soil aggregate stability but no gain in yield.
  • Authors:
    • Rice, C. W.
    • Boyles, S. B.
    • Williams, J. R.
    • Pendell, D. L.
    • Nelson, R. G.
  • Source: Review of Agricultural Economics
  • Volume: 29
  • Issue: 2
  • Year: 2007
  • Summary: This study examines the economic potential of using either no-tillage or conventional tillage with either commercial nitrogen or cattle manure to sequester soil in continuous corn production. This research uses stochastic efficiency with respect to a function to determine the preferred production systems under various risk preferences and utility-weighted certainty equivalent risk premiums to determine the carbon credit values needed to motivate adoption of systems, which sequester higher levels of carbon. The results indicate that no-tillage and cattle manure increase carbon sequestration. Carbon credits or government program incentives are not required to entice risk-averse managers to use no-tillage, but are required to encourage manure use as a means of sequestering additional carbon even at historically high nitrogen prices. New environmental rules for confined animal feeding operations may increase the demand for land to apply manure as a primary nutrient source and participation in the Environmental Quality Incentives Program, Conservation Security Program, and a carbon credit market to obtain payments to offset some or all of the costs of manure application.
  • Authors:
    • Griffin, T. S.
    • Larkin, R. P.
  • Source: Crop Protection
  • Volume: 26
  • Issue: 7
  • Year: 2007
  • Summary: Brassica crops used in crop rotations and as green manures have been associated with reductions in soilborne pests and pathogens. These reductions have been attributed to the production of volatile sulfur compounds through a process known as biofumigation, and to changes in soil microbial community structure. In this study, selected Brassica crops, including canola, rapeseed, radish, turnip, yellow mustard, and Indian mustard, were evaluated for control of various soilborne potato pathogens and diseases in culture, in greenhouse trials, and in field trials on commercial potato farms. In in vitro assays, volatiles released from chopped leaf material of Brassica crops and barley inhibited growth of a variety of soilborne pathogens of potato, including Rhizoctonia solani, Phytophthora erythroseptica, Pythium ultimum, Sclerotinia sclerotiorum, and Fusarium sambucinam, with Indian mustard resulting in nearly complete inhibition (80-100%). All Brassica crops and barley reduced inoculum levels of R. solani (20-56% reduction) in greenhouse tests, and radish, rapeseed, and Indian mustard reduced subsequent potato seedling disease by 40-83%. In an on-farm field trial at a site with a substantial powdery scab problem, Indian mustard, rapeseed, canola, and ryegrass grown as green manure rotation crops reduced powdery scab in the subsequent potato crop by 15-40%, and canola and rapeseed reduced black scurf by 70-80% relative to a standard oats rotation. At another field site where common scab was the primary disease problem, an Indian mustard green manure reduced common scab by 25%, and rapeseed, yellow mustard, and 'Lemtal' ryegrass also reduced black scurf relative to a standard ryegrass rotation. Disease reductions were not always associated with higher glucosinolate-producing crops, and were also observed with non- Brassica crops (barley and ryegrass), indicating other mechanisms and interactions are important, particularly for control of R. solani. Overall, Indian mustard was most effective for reducing powdery scab and common scab diseases, whereas rapeseed and canola were most effective in reducing Rhizoctonia diseases. These results indicate that Brassica crops have potential for use as green manures for the control of multiple soilborne disease problems.
  • Authors:
    • Burmester, C.
    • Reeves, D. W.
    • Motta, A. C. V.
    • Feng, Y.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 38
  • Issue: 19-20
  • Year: 2007
  • Summary: The impact of conservation tillage, crop rotation, and cover cropping on soil-quality indicators was evaluated in a long-term experiment for cotton. Compared to conventional-tillage cotton, other treatments had 3.4 to 7.7 Mg ha(-1) more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0- to 3- and 3- to 6-cm depths, respectively. Tillage had a strongth influence on POMc within the 0- to 3-cm depth, but cropping intensity and cover crop did not affect POW A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg(-1) within depth of 0-3 and 12-24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no-tillage cotton double-cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.
  • Authors:
    • McGawley, E. C.
    • Pontif, M. J.
  • Source: Nematropica
  • Volume: 37
  • Issue: 2
  • Year: 2007
  • Summary: Reniform nematodes that parasitize cotton and soybean can also reproduce on a wide spectrum of weed species, thereby maintaining nematode populations during the off-season. Microplot studies were conducted to evaluate the effects of three endemic weed species, morningglory ( Ipomoea lacunosa), hemp sesbania ( Sesbania exaltata), and johnsongrass ( Sorghum halepense), on reproduction of the reniform nematode, Rotylenchulus reniformison cotton (LA. 887) and soybean (Pioneer 96B21). Over two years of microplot trials, the co-culture of cotton with any of the three weed species suppressed numbers of reniform nematode juveniles in soil significantly. When grown singly, reproductive values of R. reniformis after 60 days on cotton averaged 69.0, while those for morningglory, hemp sesbania, and johnsongrass averaged 42.0, 23.5, and 18.0, respectively. Reproductive values on cotton co-cultured with morningglory averaged 38.5. Those for the cotton-hemp sesbania and cotton-johnsongrass combinations averaged 23.5 and 26.0, respectively. Nematode reproduction on soybean alone, and co-cultured with each of the three weeds, reduced reproduction of reniform nematode only in the presence of johnsongrass in two trials. Data from two subsequent 45-day duration greenhouse experiments conducted with cotton and leachates from each of the three weed species support the hypothesis that suppression of reniform nematode reproduction likely resulted from the secretion of allelopathic compounds by weed roots.
  • Authors:
    • Osborne, S. L.
    • Riedell, W. E.
    • Pikul, J. L. Jr.
  • Source: Recent Research Developments in Soil Science
  • Volume: 2
  • Year: 2007
  • Summary: Maize (Zea mays L.) grown in rotation with high residue crops generally has lower grain yield under no-till than under tilled soil management in the northern US maize belt. Hence, the research objectives were to further characterize soil physical properties, maize grain yield, and seed composition under tilled and no-till soil management following soybean ( Glycine max L.) or winter wheat ( Triticum aestivum L). The two year field study was conducted on a Barnes sandy clay loam soil (fine-loamy, mixed, superactive, frigid Calcic Hapludoll) in eastern South Dakota USA. Research plots were managed under no-till starting in 1996. Tillage treatments (fall chisel plow prior to winter wheat, fall chisel plow plus spring disk-harrow prior to maize and soybean, or no-till) were started in 2001. Tillage and previous crop treatments were arranged in a completely randomized block design with 4 replications. Soil temperatures (30 cm depth) in tilled plots after winter wheat were warmer than no-till plots in June and again in August of the 2004 growing season. In 2003, soil temperatures were very similar across tillage treatments. Soil bulk density (0 to 10 cm depth) and soil penetration resistance (0 to 7 cm depth) were much greater under no-till soil management than under tilled conditions when measured in mid-June (V6 leaf development stage). While tillage treatment affected maize seed oil concentration (4.0% in tilled, 4.3% in no-till), there were no significant previous crop or interaction effects on seed oil or protein concentration. In the warmer and drier year (2003), maize grain yield under tilled conditions was 8.2 Mg ha -1 compared with 8.7 Mg ha -1 under no-till. In the cooler and wetter year (2004), yields were 9.4 Mg ha -1 under tilled soil management and 7.4 Mg ha -1 under no-till. The no-till soil management treatment following winter wheat had 27% lower maize grain yield than the tilled treatments and the no-till following soybeans. We conclude that greater bulk density and penetration resistance levels under no-till soil management, along with cool soil conditions that typically occur in the spring in the northern US maize belt, reduced maize yield under no-till management in soils with moderately low to low internal drainage.
  • Authors:
    • Kumar, S.
    • Bishnoi, U. R.
    • Cebert, E.
  • Source: American-Eurasian Journal of Sustainable Agriculture
  • Volume: 1
  • Issue: 1
  • Year: 2007
  • Summary: In southeastern USA, winter wheat as a double crop has proved to be economically profitable and beneficial for soil management to the farmers. Winter rape ( Brassica napus) also has similar potential but its suitability as a double crop and in rotation with summer crops has not been evaluated. Therefore, performance of winter rape in rotation and as a double crop with soyabean, maize, sorghum, and cotton were evaluated for two years. Results showed that the effect of rotation on plant density during both years was significant. Rotational effects on number of pods per plant were non-significant than rape grown as fallow in 2003 but not in 2004. Rape grown after soyabean produced significantly higher seed yield in 2003 (2739 kg ha -1) and 2004 (3129 kg ha -1) than after other crops except maize (2938 kg ha -1) and fallow (2876 kg ha -1). Planting rape after fallow gave significantly the lowest economic returns during both years. Rape gave significantly higher economic returns when planted after maize ($1237) and cotton ($1169) than soyabean-rape and sorghum-rape and fallow-rape rotations in 2003. Similarly, cotton-rape ($1442) and soyabean-rape ($1393) gave significantly higher economic returns per hectare than maize-rape, sorghum-rape, and fallow-rape cropping systems.
  • Authors:
    • Schomberg, H. H.
    • Franzluebbers, A. J.
    • Endale, D. M.
  • Source: Soil & Tillage Research
  • Volume: 96
  • Issue: 1/2
  • Year: 2007
  • Summary: The type of conservation-tillage management employed could impact surface-soil properties, which could subsequently affect relationships between soil and water quality, as well as with soil C sequestration and greenhouse gas emissions. We determined soil bulk density, organic C and N fractions, plant-available N, and extractable P on Typic Kanhapludults throughout a 7-year period, in which four long-term (>10 years), no-tillage (NT) water catchments (1.3-2.7 ha each) were divided into two treatments: (1) continuation of NT and (2) paraplowing (PP) in autumn (a form of non-inversion deep ripping) with NT planting. Both summer [cotton ( Gossypium hirsutum L.), maize ( Zea mays L.), sorghum ( Sorghum bicolor L. Moench), soybean ( Glycine max L. Merr.)] and winter [wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), rye ( Secale cereale L.), crimson clover ( Trifolium incarnatum L.)] crops were NT planted throughout the study under each management system. Soil bulk density was reduced with PP compared with NT by as much as 0.15 Mg m -3, but the extent of reduction was inversely related to the time lag between PP operation and sampling event. Soil organic C became significantly enriched with time during this study under NT (0.49 Mg C ha -1 year -1), but not under PP, in which poultry litter was applied equivalent to 5.7 Mg ha -1 year -1 to all water catchments. Soil maintained a highly stratified depth distribution of organic C and N fractions and extractable P under both NT and PP. Inability to perform the PP operation in the last year of this study resulted in rapid convergence of soil bulk density between tillage systems, suggesting that PP had
  • Authors:
    • Liebig, M. A.
    • Merrill, S. D.
    • Krupinsky, J. M.
    • Tanaka, D. L.
    • Hanson, J. D.
  • Source: Agronomy Journal
  • Volume: 99
  • Issue: 4
  • Year: 2007
  • Summary: Producers need to know how to sequence crops to develop sustainable dynamic cropping systems that take advantage of inherent internal resources, such as crop synergism, nutrient cycling, and soil water, and capitalize on external resources, such as weather, markets, and government programs. The objective of our research was to determine influences of previous crop and crop residues (crop sequence) on relative seed and residue yield and precipitation-use efficiency (PUE) for the no-till production of buckwheat ( Fagopyrum esculentum Moench), canola ( Brassica napus L.), chickpea ( Cicer arietinum L.), corn ( Zea mays L.), dry pea ( Pisum sativum L.), grain sorghum ( Sorghum bicolor L.), lentil ( Lens culinaris Medik.), proso millet ( Panicum miliaceum L.), sunflower ( Helianthus annus L.), and spring wheat ( Triticum aestivum L.) grown in the northern Great Plains. Relative seed yield in 2003 for eight of the 10 crops resulted in synergistic effects when the previous crop was dry pea or lentil, compared with each crop grown on its own residue. Buckwheat, corn, and sunflower residues were antagonistic to chickpea relative seed yield. In 2004, highest relative seed yield for eight of the 10 crops occurred when dry pea was the previous crop. Relative residue yield followed a pattern similar to relative seed yield. The PUE overall means fluctuated for seven of the 10 crops both years, but those of dry pea, sunflower, and spring wheat remained somewhat constant, suggesting these crops may have mechanisms for consistent PUE and were not as dependent on growing season precipitation distribution as the other seven crops. Sustainable cropping systems in the northern Great Plains will approach an optimal scheme of crop sequencing by taking advantage of synergisms and avoiding antagonisms that occur among crops and previous crop residues.
  • Authors:
    • Anderson, R. L.
  • Source: Weed Technology
  • Volume: 21
  • Issue: 2
  • Year: 2007
  • Summary: Weed management is evolving to include cultural tactics that reduce weed populations. This study near Brookings, SD, evaluated the effect of crop sequence and tillage on seedling emergence of common sunflower across years. In the third and fourth years of the study, seedling density was sevenfold greater after 2 yr of soyabean with tillage compared with a 2-yr sequence of canola and winter wheat with no-till. Apparently, canola and winter wheat enhanced the natural decline of common sunflower seed density in soil, leading to fewer seedlings in following years. In the first year of the study, tillage increased seedling emergence of common sunflower compared with no-till; seedlings rarely emerged in canola or winter wheat. Most seedlings of common sunflower emerged in May, with more than 90% of seedlings emerging between May 7 and June 4. Cool-season crops grown with no-till may affect weed seed survival in soil in the western Corn Belt.