• Authors:
    • Petrie, S.
    • Rhinhart, K.
    • Machado, S.
  • Source: Journal of Environmental Quality
  • Volume: 35
  • Issue: 4
  • Year: 2006
  • Summary: Soil organic carbon (SOC) has beneficial effects on soil quality and productivity. Cropping systems that maintain and/or improve levels of SOC may lead to sustainable crop production. This study evaluated the effects of long-term cropping systems on C sequestration. Soil samples were taken at 0- to 10-, 10- to 20-, 20- to 30-, and 30- to 40-cm soil depth profiles from grass pasture (GP), conventional tillage (CT) winter wheat (Triticum aestivum L.)-fallow (CTWF), and fertilized and unfertilized plots of continuous winter wheat (WW), spring wheat (SW), and spring barley (Hordeum vulgare L.) (SB) monocultures under CT and no-till (NT). The samples were analyzed for soil organic matter (SOM) and SOC was derived. Ages of experiments ranged from 6 to 73 yr. Compared to 1931 SOC levels (initial year), CTWF reduced SOC by 9 to 12 Mg ha-1 in the 0- to 30-cm zone. Grass pasture increased SOC by 6 Mg ha-1 in the 0- to 10-cm zone but decreased SOC by 3 Mg ha-1 in the 20- to 30-cm zone. Continuous CT monocultures depleted SOC in the top 0- to 10-cm zone and the bottom 20- to 40-cm zone but maintained SOC levels close to 1931 SOC levels in the 10- to 20-cm layer. Continuous NT monocultures accumulated more SOC in the 0- to 10-cm zone than in deeper zones. Total SOC (0- to 40-cm zone) was highest under GP and continuous cropping and lowest under CTWF. Fertilizer increased total SOC only under CTWW and CTSB by 13 and 7 Mg ha-1 in 13 yr, respectively. Practicing NT for only 6 yr had started to reverse the effect of 73 yr of CTWF. Compared to CTWF, NTWW and NTSW sequestered C at rates of 2.6 and 1.7 Mg ha-1 yr-1, respectively, in the 0- to 40-cm zone. This study showed that the potential to sequester C can be enhanced by increasing cropping frequency and eliminating tillage.
  • Authors:
    • Chhabra, B. S.
    • Wang, Z. H.
    • Lemke, R.
    • Malhi, S. S.
  • Source: Soil & Tillage Research
  • Volume: 90
  • Issue: 1-2
  • Year: 2006
  • Summary: Management practices that simultaneously improve soil properties and yield are crucial to sustain high crop production and minimize detrimental impact on the environment. The objective of this study was to determine the influence of tillage and crop residue management on crop yield, N uptake and C removal in crop, soil organic C and N, inorganic N and aggregation, and nitrous oxide (N2O) emissions on a Gray Luvisol (Boralf) soil near Star City, Saskatchewan, Canada. The 4-year (1998-2001) field experiment was conducted with two tillage systems: no tillage (NT), and conventional tillage (CT); two levels of straw: straw retained (S), and straw removed (NS); and four rates of fertilizer N: 0, 40, 80, and 120 kg N ha-1, except no N to pea phase of the rotation. The plots were seeded to barley (Hordeum vulgare L.) in 1998, pea (Pisum sativum L.) in 1999, wheat (Triticum aestivum L.) in 2000 and canola (Brassica napus L.) in 2001. Tillage and straw treatments generally had no effect on crop yield during the first three years. But in 2001, NT produced 55, 32, and 20% greater canola seed, straw and chaff than CT, respectively, whereas straw retention increased seed and straw yield by 33 and 19% compared to straw removal. Seed, straw and chaff yield of canola increased with N rate up to 40 kg N ha-1, and root mass (0-15 cm depth) with N rate to 80 kg N ha-1. Amount of N uptake and C removed in wheat and canola generally increased with N rate, but tillage and straw management had no consistent effect. After four crop seasons, total organic C (TOC) and N (TN), light fraction organic matter (LFOM), C (LFC), and N (LFN) were generally greater with S than NS treatments. Tillage did not affect TOC and TN in soil, but LFOM, LFC, and LFN were greater or tended to be greater under NT than CT. There was no effect of tillage, straw and N fertilization on NH4-N in soil, but CT and S tended to have higher NO3-N concentration in 0-15 cm soil than NT and NS, respectively. Concentration of NO3-N increased substantially with N rate >=80 kg ha-1. The NT + S treatment had the lowest proportion (34%) of wind-erodible (12.7 mm) dry aggregates, compared to highest (50%) and lowest (18%) proportion of corresponding aggregates in CT + NS, indicating less potential for soil erosion when tillage was omitted and crop residues were retained. Amount of N lost as N2O was higher from N-fertilized than from zero-N plots, and it was substantially higher from N-applied CT plots than from N-applied NT plots. Retaining crop residues along with no-tillage improved soil properties and may also be better for the environment.
  • 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:
    • Healy, K.
    • Reichstein, I.
    • Murray, B.
  • Source: 9th International Working Conference on Stored Product Protection -- New Chemicals and Food Residues PS3-2-6324
  • Year: 2006
  • Summary: The National Residue Survey (NRS) is an operational unit of the Australian Government Department of Agriculture, Fisheries and Forestry. NRS has managed and operated residue testing programs (including meat products and grains) for over 40 years. The NRS Grains Residue Testing Program is fully industry funded via a 0.015% ad valorem levy on grain growers. This Residue Testing Program complements that undertaken by grain marketers/handlers from grower receivals to bulk storage. Noting that NRS does not have a regulatory role, the Grains Program is viewed as providing independent verification of the residue status of Australian grain at the point of out-turn for export and for receival at grain processors such as flour mills. The Grains Program covers wheat, barley, oat, sorghum, canola, field pea, chickpea and lupin. By 2007, it is expected to extend to all tradeable grains including lentil, soybean, maize, triticale, sunflower, mung bean and faba/broad bean. Each year, the Grains Program is independently reviewed and a prospective monitoring plan circulated to the Grains Council of Australia and State affiliates, and peak grain industry bodies for endorsement. The Grains Program monitoring plan specifies that approximately 5,500 grain samples are collected per annum from export shipments and containers, flour mills, feedmills, feedlots and maltsters. About 4,000 samples are collected from export shipments where every hatch of every ship from every Australian grain export terminal is sampled during loading. The monitoring plan stipulates that samples be sent to an accredited proficiency-tested laboratory and residue testing results reported to the grain marketer/handler within 14 days of sample collection. Grain samples are subjected to a chemical screen covering a range of insecticides, fungicides and environmental contaminants. These residue testing results are reported against Australian MRLs established by Food Standards Australia and New Zealand.
  • Authors:
    • Wojciak, H.
    • Adamiak, J.
    • Rychcik, B.
  • Source: Plant, Soil and Environment
  • Volume: 52
  • Issue: Special Issue
  • Year: 2006
  • Summary: A field experiment was conducted during 1992-2004 on Luvisols (formed from silty light loam) at the Experimental Station at Bacyny to investigate the response of the most important plants cultivated in Poland to monocultural cultivation. Twelve plant species were cultivated in crop rotations: (A) potato-oats-flax-winter rye-faba bean-winter triticale; (B) sugarbeet-maize-spring barley-pea-winter rape-winter wheat, and (C) each of the species in monocultures. The organic matter content in the soil plough layer (0-250 mm) in 1992, 1998 and 2004 is presented. Fractionation of humus was carried out with the Duchaufour and Jacquin method. Under the conditions of the crop rotations, organic matter content slightly increased; similar tendencies were observed in most monoculture fields. The lowest content of organic C was recorded under the conditions of continuous cultivation of pea, maize and faba bean. Humins and humus compounds (extraction II and III) had a dominant share among the determined fractions. Humic acids prevailed over fulvic acids in the crop rotation cultivations and in the most monoculture fields. However, the prevalence of fulvic acids was found under the conditions of continuous cultivation of sugarbeet, potato and winter rye.
  • Authors:
    • Harker, K. N.
    • Beckie, H. J.
    • Blackshaw, R. E.
    • Upadhyay, B. M.
    • Smith, E. G.
    • Clayton, G. W.
  • Source: Canadian Journal of Plant Science
  • Volume: 86
  • Issue: 4
  • Year: 2006
  • Summary: Integrated weed management (IWM) systems that combine seeding date, seeding rate, herbicide rate, and timing of nitrogen (N) fertilizer application were assessed for their economic performance in the Dark Brown and Black soil zones. A barley-field pea IWM system in the Black soil zone at Lacombe, Alberta, and a wheat-canola IWM system in the Dark Brown soil zone at Lethbridge, Alberta, and Scott, Saskatchewan, were used to assess contributions of seeding date (April or May), seeding rate (recommended or 150% of recommended), fertilizer timing (fall or spring), and in-crop herbicide rate (50% or 100% of recommended). The factorial set of treatments was applied in 4 consecutive years at each site. For barley-field pea production, the highest contribution margin (CM) (returns over variable production costs) was earned with 50% of the recommended herbicide rate, spring application of N fertilizer, seeding barley later at the high seeding rate, and seeding field pea early at the recommended seeding rate. This IWM system had a CM benefit of at least $51 ha(-1) compared with current common practices. The wheat-canola system results were site specific. At Lethbridge, it was more profitable to use 50% of recommended herbicide rates and to seed both crops early, with an early seeding date being very important for canola. The CM of this IWM system was $48 ha(-1) higher than current common practices. At Scott, the wheat-canola system was more profitable with spring fertilizer application, 50% of the recommended herbicide rate, and an early seeding date for canola. The best IWM system had a CM $15 to $75 ha-1 higher, depending on the year, than common practices. Our results confirmed the economic merits of using IWM practices for cereal-oilseed and cereal-pulse cropping systems in these regions of western Canada.
  • Authors:
    • Di, H. J.
    • Stewart, A.
    • Condron, L. M.
    • Stark, C.
    • O'Callaghan, M.
  • Source: New Zealand Journal of Crop and Horticultural Science
  • Volume: 34
  • Issue: 3
  • Year: 2006
  • Summary: Farming practices can have significant effects on important soil processes, including nitrogen (N) dynamics and nitrate leaching. A lysimeter experiment was conducted to determine differences in N leaching resulting from past and current crop management practices. Intact monolith lysimeters (50cm diam. x 70cm deep) were taken from sites of the same soil type that had either been under long-term organic or conventional crop management. These were then managed according to established organic and conventional practices over 2% years using the same crop rotation (barley (Hordeum vulgare L.), maize (Zea mays L.), rape (Brassica napus L. ssp. oleifera) plus a lupin green manure (Lupinus angustifolius L.)) and two fertiliser regimes, resulting in four treatments based on soil management history and current fertilisation strategy. Dry matter yield of each crop was determined after harvest and leachates were collected after significant rainfall events and analysed for total mineral N concentrations. Mineral fertilisation had a clear positive effect on yields of the first crop, whereas there were no considerable differences between treatments for the last crop owing to a significant positive effect of green manure incorporation on yields. Although there was a trend of lower mineral N leaching from organically fertilised soils (organic management: 24.2 kg N ha(-1); conventional management: 28.6), differences in N losses were not statistically significant between treatments. This shows that under the experimental conditions, leaching losses and crop yields were more strongly influenced by crop rotation and green manuring than by the presence or absence of mineral fertilisation. Overall, the study highlights the benefits of including a green manure in the crop rotation of any farming system.
  • Authors:
    • Duchovskiene, L.
    • Starkute, R.
    • Zalatorius, V.
  • Source: Straipsnis leidinyje: Sodininkystė ir daržininkystė
  • Volume: 25
  • Issue: 4
  • Year: 2006
  • Summary: In 2003-05 in Lithuanian Institute of Horticulture, in trial field for ecologically grown vegetables, plant availability for green manure and its influence on ecologically grown onions yield were evaluated. Investigated plants included: barley; barley with undersown clover; summer wheat, peas and oats; and rape. Control treatment was black fallow. The biomass of plants for green manure leaves in the soil was evaluated under different amounts of organic matter. The highest amount of green matter (43.2 t/ha) was from peas and oats; summer wheat showed 32.5 t/ha; barely with undersown clover, 30.2 t/ha; and the lowest was from barely and rape (24.5 and 27.0 t/ha, respectively). There were no significant differences in the number of Thrips tabaci between treatments. Green manure from peas and oats increase onion yield by 3.1%; green manure from summer wheat by 5.7%; and green manure from barely with undersown clover by 7.3%. The lowest impact for onion yield has had green manure from barely and rape. The highest number of weeds (191 unit/m 2) was found in onions grown after barely with undersown clover, while the lowest number of 29 unit/m 2 was in onions grown after peas and oats.
  • Authors:
    • Roostalu, H.
    • Astover, A.
    • Vasiliev, N.
    • Matveev, E.
  • Source: Agronomy Research
  • Volume: 4
  • Issue: 1
  • Year: 2006
  • Summary: For analysing agronomic efficiency and economic criteria, the results of variety comparison tests of cereals, performed in Estonia during twenty years, national statistics and the data of the survey of the Farm Accountancy Data Network (FADN) for 2000-2003 were summarised. Farms whose grain production contributed more than 75% to total output were selected for analysis. At present only -40-50% of the real yield potential of cereals is realised. In case of oilseed rape the utilisation of the yield potential is 60-65%. Among the cereals, the largest share is accounted for by barley with 25-43% and wheat with 15-29%. During four years (2000-2003), total inputs increased 21%. Total inputs were the highest in large farms. As an average for 2000-2003 FADN grain producers were profitable in all size groups but consideration of total labour costs indicates that small grain farms were unprofitable. Average farm family income was 1,376 EEK ha(-1). There is a non-linear relationship between farm size and economic indicators. Farm family income increases up to similar to 400 ha. The increase is most significant in the size range 40-200 ha where the increase in farm size by one hectare increases profit by 7.6 EEK ha(-1). Further increase will decelerate profit and the most efficient use of labour occurs in this size range as well. Cost benefit is the highest for farm size ranging from similar to 150 to 400 ha. Profit decreases with the increase in one annual work unit by 508 EEK ha(-1) and production becomes unprofitable in case a grain farm employs more than 2.6 workers per 100 ha.
  • Authors:
    • Bolland, M. D. A.
    • Brennan, R. F.
  • Source: Australian Journal of Experimental Agriculture
  • Volume: 46
  • Issue: 10
  • Year: 2006
  • Summary: Zinc (Zn) oxide is the most widely used fertiliser for the predominantly acidic to neutral soils of southwestern Australia. For these soils, the residual value of Zn oxide has been determined for wheat and lupin, but not for barley, oats, canola and triticale, which are also grown in the region. Just after termination of a long-term (17 year) field experiment that measured the residual value of Zn oxide for wheat, soil samples were collected from selected plots to use in 2 glasshouse experiments. The field experiment was on previously unfertilised, newly cleared duplex soil (sand with much lateritic ironstone gravel over clay) and before the experiment started DTPA extractable Zn for the top 10 cm of soil was 17 years for triticale. The 1.0 kg Zn/ha treatment remained fully effective for all crop species. As determined from projected estimates of the data, the time taken for Zn concentrations in young mature growth to reach critical values, the residual value of the 0.5 and 1.0 kg Zn/ ha treatments were least for wheat, barley and oats, were greater for lupin and canola, and greatest for triticale. There were a total of 7 wheat crops and 10 pasture years during the 17 years of the field experiment. For the 0.5 and 1.0 kg Zn/ha treatment applied in the field in 1983, 30 - 34% of the applied Zn was removed in grain of the 7 wheat crops grown before soil samples were collected to do the glasshouse experiments. The pasture was grazed by sheep and it was estimated that 16 - 24% of the Zn applied in 1983 may have been removed in wool and meat. Removal of Zn in grain and animal products therefore decreased the residual value of the Zn oxide fertiliser.