• Authors:
    • Kumar, P.
    • Yadav, S. K.
    • Kumar, M.
    • Rinwa, R . S.
  • Source: Haryana Journal of Horticultural Sciences
  • Volume: 35
  • Issue: 3/4
  • Year: 2006
  • Summary: An experiment was conducted during 2003-04 and 2004-05 to study the nitrogen, phosphorus and potassium uptake by different cropping systems in semiarid tract of Haryana, India. The experiment comprised 7 cropping systems, viz., pearl millet-wheat, pearl millet-mustard, soyabean-wheat-cowpea, sorghum-wheat, pearl millet-potato-green gram, pearl millet-field pea-maize, and cotton-wheat. The uptake of nitrogen, phosphorus and potassium by the crops varied among different cropping systems. The nutrient uptake was higher in high yielding cropping systems. The nutrients uptake was highest in pearl millet-potato-green gram cropping system.
  • Authors:
    • Deen, W.
    • Janovicek, K.
    • Meyer-Aurich, A.
    • Weersink, A.
  • Source: Agronomy Journal
  • Volume: 98
  • Issue: 5
  • Year: 2006
  • Summary: The objective of our research was to identify economically efficient corn (Zea mays L.) based tillage-rotation combinations using a 20-yr data set from a long-term experiment in Ontario, Canada. Seven rotations in two tillage systems (moldboard and chisel plow) were analyzed. We found multiple benefits associated with diversifying rotations in both tillage systems The integration of soybean [Glycine mar (L.) Merr.] or soybean and wheat (Triticum aestivum L.) resulted in 7 to 11% higher corn yields in the chisel tillage system. In the plow tillage system corn yield in rotation with soybean and wheat increased by 5%, when wheat was underseeded with red clover (Trifolium pratense L.). These diversified rotations resulted in an increase in yearly net returns of $51 to $64 in the moldboard tillage system and $96 to $108 in the chisel tillage system. The diversification of rotations reduces variance of net return and thus makes the rotations attractive to risk averse producers. Furthermore diversified rotations showed less response to price changes. Diversified rotations evaluated in this study also proved to be less affected by increasing energy costs. Red clover seeded into wheat resulted in 5% higher yields for the following corn crop in the moldboard system. Rotations that included red clover cover lowered production risk but did not have higher net returns than comparable rotations without red clover. However, the potential for red clover to reduce N fertilization requirements for the following corn, was not considered in this study. Yield penalties due to chisel plowing with financial consequences were only observed in continuous corn. In all other rotations the effect of tillage was negligible. An increase in energy costs forces farmers to switch to crops with lower inputs rather than switch to reduced tillage.
  • Authors:
    • Kevan, P. G.
    • Belaoussoff, S.
    • Clements, D. R.
    • Murphy, S. D.
    • Swanton, C. J.
  • Source: Weed Science
  • Volume: 54
  • Issue: 1
  • Year: 2006
  • Summary: In a 6-yr study on four farms (36 fields) in Ontario, Canada, we tested the effects of tillage (moldboard, chisel plow, no tillage) and crop rotations (continuous corn, corn-soybean, corn-soybean-winter wheat) on emerged and seedbank weed species diversity and density Aside from the imposed experimental treatments, all other management was generally consistent among farms. Tillage had the largest effect on weed diversity and density. No tillage promoted the highest weed species diversity, chisel plow was intermediate, and moldboard plow resulted in the lowest species diversity. These results are consistent with ecological succession theory. The increase in weed species diversity resulted from 20 species being associated with no tillage systems, 15 of which were winter annuals, biennials, or perennials. Emerged weed density was affected only by tillage. Over 6 yr, seedbank declined in no-tillage systems from 41,000 to 8,000 seeds m(-3). Crop yields were not affected by tillage or crop rotation. In practical terms, reduced tillage in combination with a good crop rotation may reduce weed density and expenditures on weed management.
  • Authors:
    • Tolbert, V. R.
    • Mays, D. A.
    • Nyakatawa, E. Z.
    • Green, T. H.
    • Bingham, L.
  • Source: Biomass and Bioenergy
  • Volume: 30
  • Issue: 7
  • Year: 2006
  • Summary: Renewable energy sources such as bioenergy crops have significant potential as alternatives to fossil fuels. Potential environmental problems arising from soil sediment and nutrient losses in runoff water from bioenergy crops need to be evaluated in order to determine the sustainability and overall feasibility of implementing bioenergy development strategies. This paper discusses runoff, sediment, N, and total P losses from agricultural land (continuous cotton (Gossypium hirsutum L.)) converted to short-rotation sweetgum (Liquidamber styraciflua L.) plantations with and without fescue (Festuca elatior L.) and switchgrass (Panicum virgatum L.) bioenergy crops, compared to corn (Zea mays L.), on a Decatur silt loam soil in north Alabama, from 1995 to 1999. Runoff volume was significantly correlated to total rainfall and sediment yield in each year, but treatment differences were not significant. Sweetgum plots produced the highest mean sediment yield of up to 800 kg ha(-1) compared to corn and switchgrass plots, which averaged less than 200 kg ha(-1). Runoff NH4+ N losses averaged over treatments and years for spring season (3.1 kg ha(-1)) were three to five times those for summer, fall, and winter seasons. Runoff NO3- N for no-till corn and switchgrass plots in spring and summer were five to ten times that for sweetgum plots. No-till corn and switchgrass treatments had 2.4 and 2.1 kg ha(-1) average runoff total P, respectively, which were two to three times that for sweetgum treatments. Growing sweetgum with a fescue cover crop provides significantly lower risk of water pollution from sediment, runoff NH4+ N, and NO3- N. (c) 2006 Published by Elsevier Ltd.
  • Authors:
    • Mallory-Smith, C.
    • William, R. D.
    • Peachey, B. E.
  • Source: Weed Technology
  • Volume: 20
  • Issue: 1
  • Year: 2006
  • Summary: The effects of spring tillage sequence on summer annual weed populations were evaluated over two cycles of a 3-year crop rotation of snap beans ( Phaseolus vulgaris), sweetcorn ( Zea mays), and winter wheat ( Triticum aestivum). Continuous no-till (N) planting of vegetable crops each spring (NNNN) reduced summer annual weed density by 63-86% compared with that of continuous conventional tillage (CCCC), depending upon the site and herbicide level. Hairy nightshade ( Solanum sarrachoides) populations were reduced by 88 to 96% when spring tillage was eliminated from the crop rotation. The effects of the NNNN spring tillage sequence on weed density were similar at two sites even though the crop rotations at the two sites began with different crops. The rotational tillage sequence of NCNC at the East site, in a crop rotation that began with maize, reduced summer annual weed density by 46-51% compared with that of continuous conventional tillage and planting (CCCC) at low and medium herbicide rates, respectively. In contrast, the tillage sequence of CNCN in the same crop rotation and at the same site increased weed density by 80% compared with that of CCCC at a low herbicide rate. The effects of the NCNC and CNCN rotational tillage sequences on weed density were reversed at the West site, and was probably caused by pairing sweetcorn with conventional tillage rather than no-tillage. The reduction in summer annual weed density caused by reduced spring tillage frequency did not significantly increase crop yields.
  • 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:
    • 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:
    • 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:
    • Rosenberg, N. J.
    • Izaurralde, R. C.
    • Thomson, A. M.
    • He, X. X.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 114
  • Issue: 2/4
  • Year: 2006
  • Summary: For thousands of years, the Huang-Hai Plain in northeast China has been one of the most productive agricultural regions of the country. The future of this region will be determined in large part by how global climatic changes impact regional conditions and by actions taken to mitigate or adapt to climate change impacts. One potential mitigation strategy is to promote management practices that have the potential to sequester carbon in the soils. The IPCC estimates that 40 Pg of C could be sequestered in cropland soils worldwide over the next several decades; however, changes in global climate may impact this potential. Here, we assess the potential for soil C sequestration with conversion of a conventional till (CT) continuous wheat system to a wheat-corn double cropping system and by implementing no till (NT) management for both continuous wheat and wheat-corn systems. To assess the influence of these management practices under a changing climate, we use two climate change scenarios (A2 and B2) at two time periods in the EPIC agro-ecosystem simulation model. The applied climate change scenarios are from the HadCM3 global climate model for the periods 2015-2045 and 2070-2099 which projects consistent increases in temperature and precipitation of greater than 5degreesC and up to 300 mm by 2099. An increase in the variability of temperature is also projected and is, accordingly, applied in the simulations. The EPIC model indicates that winter wheat yields would increase on average by 0.2 Mg ha -1 in the earlier period and by 0.8 Mg ha -1 in the later period due to warmer nighttime temperatures and higher precipitation. Simulated yields were not significantly affected by imposed changes in crop management. Simulated soil organic C content was higher under both NT management and double cropping than under CT continuous wheat. The simulated changes in management were a more important factor in SOC changes than the scenario of climate change. Soil C sequestration rates for continuous wheat systems were increased by an average of 0.4 Mg ha -1 year -1 by NT in the earlier period and by 0.2 Mg ha -1 year -1 in the later period. With wheat-corn double cropping, NT increased sequestration rates by 0.8 and 0.4 Mg ha -1 year -1 for the earlier and later periods, respectively. The total C offset due to a shift from CT to NT under continuous wheat over 16 million hectares in the Huang-Hai Plain is projected to reach 240 Tg C in the earlier period and 180 Tg C in the later period. Corresponding C offsets for wheat-corn cropping are 675-495 Tg C.
  • 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.