• Authors:
    • Spiridon, C.
    • Rotarescu, M.
    • Raranciuc, S.
    • Guran, M.
    • Popov, C.
    • Vasilescu, S.
    • Gogu, F.
  • Source: Probleme de Protectia Plantelor
  • Volume: 34
  • Issue: 1/2
  • Year: 2006
  • Summary: This paper summarizes the harmful pests and pathogens infecting cereals and legumes (grown for grain, industrial purposes and fodder production) in Romania in 2005. The soil and seed pathogens include: Tilletia spp. and Fusarium spp. in wheat; Ustilago nuda [ U. segetum var. nuda] and Pyrenophora graminea in barley; Pythium spp. and Fusarium spp. in maize; Sclerotinia sclerotiorum, Botrytis cinerea, Plasmopara helianthi [ Plasmopara halstedii] and Orobanche cumana in sunflower; and Fusarium spp. and Pythium spp. in pea, bean and soyabean. Foliar and ear diseases include: Erysiphe spp., Septoria spp., Pyrenophora graminea, Puccinia spp. and Fusarium spp. in wheat and barley; U. maydis [ U. zeae], Helminthosporium turcicum [ Setosphaeria turcica], Fusarium spp. and Nigrospora oryzae [ Khuskia oryzae] in maize; Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria spp. and Phomopsis spp. in sunflower; and Erysiphe spp. and Septoria spp. in rape. Soil pests included: Zabrus tenebrioides and Agriotes spp. in spiked cereals; Tanymecus dilaticollis and Agriotes spp. in maize and sunflower; Delia platura in beans; Phyllotreta atra in rape and mustard; Aphthona euphorbiae in linseed; and Sitona spp. and Agriotes spp. in lucerne and clover. Pests that attack aerial parts and seeds include: Eurygaster integriceps, Lema melanopa [ Oulema melanopus] and Anisoplia spp. in wheat, barley and oats; Ostrinia nubilalis and Diabrotica virgifera virgifera in maize; Thrips linarius in linseed; Athalia rosae, Meligethes aeneus and Brevicoryne brassicae in rape and mustard; Hypera variabilis [ H. postica], Semiothisa clathrata, Bruchophagus roddi and Subcoccinella vigintiquattuorpunctata in lucerne and clover.
  • Authors:
    • Garbuio, F. J.
    • Barth, G.
    • Caires, E. F.
  • Source: Soil & Tillage Research
  • Volume: 89
  • Issue: 1
  • Year: 2006
  • Summary: Brazil has extensive pasturelands that could be used, in part, for grain production. A no-till system was established on pastureland to obtain a suitable method for liming upon conversion from pasture to a no-till cropping system. The study was conducted during the period from 1998 to 2003, in Parana State (Brazil), on a clayey, kaolinitic, thermic Rhodic Hapludox. Soil chemical properties and grain production were evaluated after application of dolomitic lime. The experimental treatments were: control (no lime), split application of lime on the surface (three yearly applications of 1.5 t ha -1), surface lime (4.5 t ha -1), and incorporated lime (4.5 t ha -1). The lime rate was calculated to raise the base saturation in the topsoil (0-0.20 m) to 70%. The cropping sequence was: soyabean ( Glycine max L. Merril), barley ( Hordeum distichum L.), soyabean, wheat ( Triticum aestivum L.), soyabean, corn ( Zea mays L.), and soyabean. When surface-applied, liming neutralized acidity and increased exchangeable Ca 2++Mg 2+ to a depth of 0.10 m, and to a depth of 0.20 m, when incorporated. Split application of lime on the surface resulted in a slower neutralization reaction only in the first year after liming. Soil pH increased with liming and resulted in a decline of exchangeable Al 3+ and an increase in base saturation. At 0-0.05 m depth, lime incorporation resulted in lower levels of soil organic matter than surface application. It took 4-5 years after lime incorporation for soil organic matter to return to its baseline value. Liming increased grain yield in only one crop of soyabean, and only when lime was surface-applied at the full rate. However, cumulative grain yield was higher with liming than in the control treatment (no lime), regardless of the application method. Surface application of lime, at either full or split rates, was the best alternative to neutralize soil acidity when establishing a no-till system on pastureland because, in addition to conserving soil structure, it provided a greater economic return.
  • Authors:
    • Raundal, P. U.
    • Kambale, A. B.
    • Chaudhari, P. M.
    • Chitodkar, S. S.
  • Source: International Journal of Agricultural Sciences
  • Volume: 2
  • Issue: 2
  • Year: 2006
  • Summary: A study was conducted in Maharashtra, India during 2002, 2003 and 2004 under rainfed conditions to evaluate the effect of intercropping with pigeon pea (cv. BSMR-78), sorghum (cv. CHS-14) and cotton (cv. Y-1) on the productivity of soyabean (cultivars JS-335 and MACS-124). The spacings were 30 * 10, 65 * 20, 45 * 15 and 45 * 22.5 cm for soyabean, pigeon pea, sorghum and cotton, respectively, under soyabean intercropping, at 3:1 row proportion. Soyabean + pigeon pea produced the highest soyabean equivalent yield (24.06 q/ha), gross monetary returns (Rs. 30 322/ha), net monetary returns (Rs. 20 010/ha), land equivalent ratio (1.38) and benefit:cost ratio (2.92).
  • Authors:
    • Cavigelli, M. A.
    • Szlavecz, K.
    • Clark, S.
    • Purrington, F.
  • Source: Environmental Entomology
  • Volume: 35
  • Issue: 5
  • Year: 2006
  • Summary: Ground beetle assemblages were compared in organic, no-till, and chisel-till cropping systems of the USDA Farming Systems Project in Maryland. The cropping systems consisted of 3-yr rotations of corn ( Zea mays L.), soybean ( Glycine max L. Merr.), and wheat ( Triticum aestivum L.) that were planted to corn and soybean during the 2 yr of field sampling (2001-2002). Each year, ground beetles were sampled using pitfall traps during three 9- to 14-d periods corresponding to spring, summer, and fall. A total of 2,313 specimens, representing 31 species, were collected over the 2 yr of sampling. The eight most common species represented 87% of the total specimens collected and included Scarites quadriceps Chaudoir, Elaphropus anceps (LeConte), Bembidion rapidum (LeConte), Harpalus pensylvanicus (DeGeer), Poecilus chalcites (Say), Clivina impressefrons LeConte, Agonum punctiforme (Say), and Amara aenea (DeGeer). Canonical variates analysis based on the 10 most abundant species showed that the carabid assemblages in the three cropping systems were distinguishable from each other. The organic system was found to be more different from the no-till and chisel-till systems than these two systems were from each other. In 2002, ground beetle relative abundance, measured species richness, and species diversity were greater in the organic than in the chisel-till system. Similar trends were found in 2001, but no significant differences were found in these measurements. Relatively few differences were found between the no-till and chisel-till systems. The estimated species richness of ground beetles based on several common estimators did not show differences among the three cropping systems. The potential use of ground beetles as ecological indicators is discussed.
  • Authors:
    • Cook, R. J.
  • Source: PNAS, Proceedings of the National Academy of Sciences
  • Volume: 103
  • Issue: 49
  • Year: 2006
  • Summary: The defining features of any cropping system are (i) the crop rotation and (ii) the kind or intensity of tillage. The trend worldwide starting in the late 20th century has been (i) to specialize competitively in the production of two, three, a single, or closely related crops such as different market classes of wheat and barley, and (ii) to use direct seeding, also known as no-till, to cut costs and save soil, time, and fuel. The availability of glyphosate- and insect-resistant varieties of soybeans, corn, cotton, and canola has helped greatly to address weed and insect pest pressures favored by direct seeding these crops. However, little has been done through genetics and breeding to address diseases caused by residue- and soil-inhabiting pathogens that remain major obstacles to wider adoption of these potentially more productive and sustainable systems. Instead, the gains have been due largely to innovations in management, including enhancement of root defence by antibiotic-producing rhizosphere-inhabiting bacteria inhibitory to root pathogens. Historically, new varieties have facilitated wider adoption of new management, and changes in management have facilitated wider adoption of new varieties. Although actual yields may be lower in direct-seed compared with conventional cropping systems, largely due to diseases, the yield potential is higher because of more available water and increases in soil organic matter. Achieving the full production potential of these more-sustainable cropping systems must now await the development of varieties adapted to or resistant to the hazards shown to account for the yield depressions associated with direct seeding.
  • Authors:
    • Vyn, T.
    • Janovicek, K.
    • Deen, B.
    • Lapen, D.
  • Source: ADVANCES IN GEOECOLOGY
  • Volume: 38
  • Year: 2006
  • Summary: In corn/soybean/wheat rotations in Ontario, Canada, tillage is often conducted intermittently to remediate compaction, address residues, incorporate nutrients or to level the surface. To determine the impact of intermittent tillage on no-till soil structure and crop yield, a 10-year study was initiated in 1995 at the Woodstock Research Station, University of Guelph. Specific objectives were (1) to compare the yield potential of corn, soyabean and wheat under short term and long-term no-till, and (2) to determine the best time to conduct intermittent tillage in a corn/soybean/wheat rotation. Tillage increased corn, soyabean and wheat yields in comparison to both short-term and long-term no-till. No-till soyabean yields did not improve with increasing years under no-till. Corn yields were reduced under first year no-till, but by the second year of no-till, corn yields were equal to long term no-till yields. In a corn/soybean/wheat rotation occasional tillage should be conducted in advance of corn.
  • Authors:
    • Mohamed, A. E. M.
    • Arab, Y. A.
    • El-Shehaby, A. I.
  • Source: Egyptian Journal of Agricultural Research
  • Volume: 84
  • Issue: 1
  • Year: 2006
  • Summary: Growing some summer crops - preceding garlic - in heavily infested potted soil significantly reduced white rot disease (Sclerotium cepivorum) of garlic. Reductions in disease incidence obtained with sugarcane, roquette [ Eruca vesicaria] and sorghum as intercrops were 80.0, 73.3 and 66.7% of the control treatment, respectively. Reductions in disease incidence obtained with maize, squash, pepper, soyabean, cotton, sesame, cowpea and roselle ranged between 53.3 and 40.0%. Cauliflower, lucerne, broad bean, nigella, Egyptian clover, coriander and roquette grown in pots, as winter crops preceding garlic, exhibited 46.7-26.7% reduction in white rot disease. Intercropping cauliflower, coriander and roquette with garlic reduced the disease by 46.0-53.8%. Seedling root exudates of cauliflower, coriander and sorghum significantly reduced mycelial growth of S. cepivorum on PDA plates more than did radish and sugarcane. Cauliflower exhibited the highest reduction in mycelial growth, followed by sorghum and coriander. Ascending rates of cauliflower root exudates resulted in a higher reduction in fungus growth. Counts of fungi were significantly higher in soil of sorghum and roquette compared with sugarcane and coriander, while coriander rhizosphere yielded the highest density of fungi. Actinomycetes were detected in the rhizosphere at a highest count with coriander but were completely absent in the soil. Bacteria, in contrast, existed only in the soil where actinomycetes were completely absent. The highest count of bacteria was detected in sorghum soil. Actinomycetes inhabited soil only while bacteria and fungi existed in soil and rhizosphere of cauliflower, radish and garlic intercropped with the two crops. Cauliflower significantly increased counts of fungi and bacteria in rhizosphere when intercropped with garlic compared with those detected with garlic alone. Some recommendations are made.
  • Authors:
    • Yang, H. S.
    • Amos, B.
    • Burba, G. G.
    • Suyker, A. E.
    • Arkebauer, T. J.
    • Knops, J. M.
    • Walters, D. T.
    • Cassman, K. G.
    • Dobermann, A.
    • Verma, S. B.
    • Ginting, D.
    • Hubbard, K. G.
    • Gitelson, A. A.
    • Walter-Shea, E. A.
  • Source: Agricultural and Forest Meteorology
  • Volume: 131
  • Issue: 1-2
  • Year: 2005
  • Summary: Carbon dioxide exchange was quantified in maize ( Zea mays)-soybean ( Glycine max) agroecosystems employing year-round tower eddy covariance flux systems and measurements of soil C stocks, CO 2 fluxes from the soil surface, plant biomass, and litter decomposition. Measurements were made in 3 cropping systems: (a) irrigated continuous maize; (b) irrigated maize-soybean rotation; and (c) rainfed maize-soybean rotation during 2001-2004. The study was conducted at the University of Nebraska Agricultural Research and Development Centre near Mead, Nebraska, USA. Because of a variable cropping history, all 3 sites were uniformly tilled by disking prior to initiation of the study. Since then, all sites are under no-till, and crop and soil management follow best management practices prescribed for production-scale systems. Cumulative daily gain of C by the crops (from planting to physiological maturity), determined from the measured eddy covariance CO 2 fluxes and estimated heterotrophic respiration, compared well with the measured total above and belowground biomass. Two contrasting features of maize and soyabean CO 2 exchange are notable. The value of integrated gross primary productivity (GPP) for both irrigated and rainfed maize over the growing season was substantially larger (ca. 2:1 ratio) than that for soyabean. Also, soyabean lost a larger portion (0.80-0.85) of GPP as ecosystem respiration (due, in part, to the large amount of maize residue from the previous year), as compared to maize (0.55-0.65). Therefore, the seasonally integrated net ecosystem production (NEP) in maize was larger by a 4:1 ratio (approximately), as compared to soyabean. Enhanced soil moisture conditions in the irrigated maize and soyabean fields caused an increase in ecosystem respiration, thus eliminating any advantage of increased GPP and giving about the same values for the growing season NEP as the rainfed fields. On an annual basis, the NEP of irrigated continuous maize was 517, 424, and 381 g C m -2 year -1, respectively, during the 3 years of our study. In rainfed maize, the annual NEP was 510 and 397 g C m -2 year -1 in years 1 and 3, respectively. The annual NEP in the irrigated and rainfed soyabean fields were in the range of -18 to -48 g C m -2. Accounting for the grain C removed during harvest and the CO 2 released from irrigation water, our tower eddy covariance flux data over the first 3 years suggest that, at this time: (a) the rainfed maize-soybean rotation system is C neutral; (b) the irrigated continuous maize is nearly C neutral or a slight source of C; and (c) the irrigated maize-soybean rotation is a moderate source of C. Direct measurement of soil C stocks could not detect a statistically significant change in soil organic carbon during the first 3 years of no-till farming in these 3 cropping systems.
  • Authors:
    • Hons, F.
    • Wright, A.
  • Source: Biology and Fertility of Soils
  • Volume: 41
  • Issue: 2
  • Year: 2005
  • Summary: Management practices, such as no tillage (NT) and intensive cropping, have potential to increase C and N sequestration in agricultural soils. The objectives of this study were to investigate the impacts of conventional tillage (CT), NT, and cropping intensity on soil organic C (SOC) and N (SON) sequestration and on distribution within aggregate-size fractions in a central Texas soil after 20 years of treatment imposition. Tillage regime and cropping sequence significantly impacted both SOC and SON sequestration. At 0-5 cm, NT increased SOC storage compared to CT by 33% and 97% and SON storage by 25% and 117% for a sorghum/wheat/soybean (SWS) rotation and a continuous sorghum monoculture, respectively. Total SOC and SON storage at both 0-5 and 5-15 cm was greater for SWS than continuous sorghum regardless of tillage regime. The majority of SOC and SON storage at 0-5 cm was observed in 250-m to 2-mm aggregates, and at 5-15 cm, in the >2-mm and 250-m to 2-mm fractions. Averaged across cropping sequences at 0-5 cm, NT increased SOC storage compared to CT by 212%, 96%, 0%, and 31%, and SON storage by 122%, 92%, 0%, and 37% in >2-mm, 250-m to 2-mm, 53- to 250-m, and
  • Authors:
    • Hons, F.
    • Wright, A.
  • Source: Soil Science Society of America Journal
  • Volume: 69
  • Issue: 1
  • Year: 2005
  • Summary: No-tillage (NT) has the potential to enhance C and N sequestration in agricultural soils of the southern USA, but results may vary with crop species. The objectives of this study were to investigate the impacts of NT, conventional tillage (CT), and crop species on soil organic carbon (SOC) and nitrogen (SON) sequestration and distribution within aggregate-size fractions in a central Texas soil after 20 yr of management. No-tillage increased SOC over CT at the 0- to 5-cm depth by 97, 47, and 72%, and SON by 117, 56, and 44% for continuous grain sorghum [ Sorghum bicolor (L.) Moench], wheat ( Triticum aestivum L.), and soyabean [ Glycine max (L.) Merr.], respectively. Crop species had significant impacts on SOC and SON sequestration. On average, the wheat monoculture had greater SOC (9.23 Mg C ha -1) at the 0- to 5-cm depth than sorghum (6.75 Mg C ha -1) and soyabean (7.05 Mg C ha -1). No-tillage increased the proportion of >2-mm and 250-m to 2-mm macroaggregate fractions in soil compared with CT. At the 0- to 5-cm depth, NT increased SOC compared with CT by 158% in macroaggregate fractions, but only 40% in 2-mm, 250-m to 2-mm, 53- to 250-m, and