• Authors:
    • Janzen, H. H.
    • Ellert, B. H.
    • McKenzie, R. H.
    • Bremer, E.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 4
  • Year: 2011
  • Summary: Agroecosystems provide a range of benefits that are strongly influenced by cropping practice. Crop productivity and C, N, and greenhouse gas (GHG) balances were evaluated in an 18-yr cropping system study on an Aridic Haplustoll in the northern Great Plains. Application of synthetic fertilizers consistently increased crop yield and soil organic carbon (SOC), with greatest impact in perennial grass and continuous wheat ( Triticum aestivum L.) rotations and least impact in rotations with fallow or annual legumes. Based on N balance, N inputs other than fertilizer were 16 to 30 kg N ha -1 yr -1 in rotations without legumes and 62 kg N ha -1 yr -1 in a legume-wheat (LW) rotation, while losses of synthetic fertilizer N were 32% in annual crop rotations and 3% in perennial grass. Due to large gains in SOC, perennial grass reduced atmospheric GHG by 20 to 29 Mg CO 2 equivalent (eq.) ha -1 during the 18 yr of this study. For annual crop rotations, seed yield ranged from 1.2 to 2.5 Mg ha -1 yr -1, protein yield from 0.20 to 0.41 Mg ha -1 yr -1, and GHG intensity from 0 to 0.5 Mg CO 2 eq. Mg -1 seed. Fertilized continuous wheat had the highest crop productivity and lowest net GHG intensity, while an annual LW rotation had the highest protein productivity and among the lowest GHG intensities (0.2 Mg CO 2 eq. Mg -1 seed). Further evaluation at broader temporal and spatial scales is necessary to account for future changes in SOC and differences in use of crop products.
  • Authors:
    • VandenBygaart, A. J.
    • Zentner, R. P.
    • Lemke, R.
    • May, W. E.
    • Holzapfel, C. B.
    • Campbell, C. A.
    • Lafond, G. P.
  • Source: Canadian Journal of Plant Science
  • Volume: 91
  • Issue: 3
  • Year: 2011
  • Summary: We analyzed the agronomic data from a 50-yr crop rotation experiment being conducted on a fine-textured, thin Black Chernozem at Indian Head, Saskatchewan in Canada. Our objective was to determine how a change from conventional-till to no-till, together with an increase in N fertilizer rates recommended by the Saskatchewan Soil Testing Laboratory has affected wheat yields and N and P balance in the systems over the past 20 yr. The treatments assessed were fertilized (N-P) and unfertilized fallow-wheat ( Triticum aestivum L.) (F-W), F-W-W, and continuous wheat (ContW), and unfertilized legume green manure (LGM)-W-W and F-W-W-brome ( Bromus inermis Leyss.)/alfalfa ( Medicago sativa L.) hay (H)-H-H. On average, N applied to wheat grown on fallow was 6 kg ha -1 yr -1 from 1957 to 1989 and 57 kg ha -1 yr -1 from 1990 to 2007; for wheat grown on stubble, the N rates were 21 kg ha -1 yr -1 from 1957 to 1977 and 85 kg ha -1 yr -1 thereafter. Crops received P at 10 kg ha -1 yr -1. On average, fertilizer increased wheat yield of fallow-wheat by 31%; the hay system increased fallow-wheat yield by 26% compared with unfertilized fallow-wheat in F-W-W, and the LGM system increased it by 14%. Effects were greater on stubble crop than on fallow crop, with fertilizer increasing the yield of wheat grown on stubble in the monoculture system by 114%, the hay system increasing it by 83% and the LGM system increasing it by 37%. The legume-containing rotations increased yields by increasing the N supplying capacity of the soil with the hay system being more effective than the LGM because legumes occurred more frequently in the hay rotation (3 in 6 yr vs. 2 in 6 yr). The benefit of the legume-containing systems on wheat yield may have been restricted because this unfertilized system steadily depleted available soil P. Average annualized wheat production in F-W, F-W-W and ContW rotations was unaffected by cropping frequency for the unfertilized systems, but it was directly proportional to cropping frequency for the fertilized systems. Annualized wheat production for the LGM-W-W rotation was 18% greater than for unfertilized F-W-W, but 41% less than for the fertilized F-W-W. Annualized wheat production in the hay-containing rotation was 32% less than in the unfertilized F-W-W rotation because of the less frequent presence of wheat in the hay system. Greater rates of N fertilizer in the later years increased yields and grain N content; this resulted in less residual NO 3-N in the soil compared with previous years with lower fertilizer N. Thus, we expect there will be less likelihood of NO 3 leaching under fallow-containing systems under no-till when updated fertilizer recommendations are used compared with previous results under conventional tillage with lower rates of N applications.
  • Authors:
    • Campos-Magana, S. G.
    • Cadena-Zapata, M.
  • Source: Campos-Magana, SG
  • Volume: 42
  • Issue: 4
  • Year: 2011
  • Summary: A five year field experiment was conducted to assess the interaction between soil tillage levels, maize-sorghum-legume rotation and two levels of chemical fertilization at the rain feed tropical region of southeast Mexico. The purpose of this research work was to asses this interaction over the variation of some soil quality indices and the effect on the productivity of the soil-grain yield. The treatments for soil tillage were zero till and the intensive traditional soil tillage of the region. Crop rotations employed were five years maize (mmmmm), five years sorghum (sssss), two rotations; (smsms) and (msmsm) and two intercropping of legumes (f)-cereals, (fsfsf) and (fmsmf). Ninety two and 136 units of nitrogen were the two levels of fertilization and were applied only to the cereals. The evaluated soil index in the first and fifth year were organic matter (mo), water infiltration rate (ir), aggregate stability (as), ph, biomass microbiana (mb), nitrogen soluble nitrogen, soil density (sd), soil depth (sd), electrical conductivity (ec) and availability of nutrients. In general terms, the best grain yield for both sorghum and maize were obtained with the no till treatment although no big differences were observed between them. The five year sorghum mean yield under no till with fertilization levels 1 and 2 were 3.6 and 4.5 Mg/ha, whereas, with conventional tillage these were just 3.1 and 4.1 Mg/ha, respectively. The grain yield of maize with level 2 of nitrogen, with zero and traditional till were 5.1 and 4.6 Mg/ha; however, with nitrogen level 1 there were no apparent advantages of the first treatment (3.8 Mg/ha in both cases). The type of crop rotation and soil tillage level mainly affected the chemical soil index at 0 to 5 cm depth. However, no effect occurred with the way of handling crop residues and with the levels of chemical fertilization. The main values of electrical conductivity were attributed to an increase in the solubility of some elements. It was also observed that, under no till, there was an increase of the levels of soluble carbon.
  • Authors:
    • Poswal, R. S.
    • Yadav, A.
    • Gupta, R. K.
    • Gill, S. C.
    • Chhokar, R. S.
    • Kumar, V.
    • Sharma, R. K.
    • Kumar, A.
    • Mehta, A.
    • Kleemann, S. G. L.
    • Cummins, J. A.
    • Coventry, D. R.
  • Source: Field Crops Research
  • Volume: 123
  • Issue: 3
  • Year: 2011
  • Summary: This article reports on field experiments with 4 different rotations that are commonly used throughout Haryana in NW India (rice-wheat, cotton-wheat, pearl millet-wheat, cluster bean-wheat), where we assess wheat yield and chapatti quality measures with different crop establishment methods and input of micronutrients. In a series of experiments conducted on farmers' fields in 2007-2008 and 2008-2009 winter seasons, the addition of micronutrients and sulphur to wheat crops was used alongside the use of a common farmer practice, the use of farmyard manure (FM) and best practice inputs of N-fertilizer (150 kg N ha -1), P-fertilizer (26 kg P ha -1) and K-fertilizer (33 kg K ha -1). The application of FM with the recommended NPK treatment produced 9-13% more grain yield in the rice-wheat rotation when compared with the recommended NPK only treatment. Given that the farm sites used here had low levels of soil P, this may suggest that the recommended rate of 26 kg P ha -1 for the rice-wheat rotation is too low. The addition of FM did not improve any grain quality outcomes at any of the sites. There were no yield responses with S application with any of the rotations but the S input resulted in more wheat protein from all sites (average 8%). The addition of S also gave similar increases in grain hardness and the chapatti score. The inclusion of micronutrients (boron, copper, iron, zinc and manganese) with the recommended NPK treatment did not increase the grain yield at any of the sites when compared with the recommended NPK treatment, and sometimes, but not consistently, gave small responses with protein, grain hardness and chapatti score. In concurrent experiments wheat growth and chapatti quality were compared in zero till and conventionally sown systems, and with and without S fertilizer amendment. Here too there were no grain yield responses to S, and the protein, grain hardness and chapatti score were increased with S addition. Grain yields with zero till and conventional wheat were similar in the rice-wheat system and zero till sowing resulted in small increases in yield at all of the non-rice sites. The grain from the zero till treatments had higher protein (1-3%), grain hardness (3-10%) and chapatti score from all 4 rotations. Zero till has substantial adoption in the rice-wheat districts of Haryana but little farmer awareness and adoption in the areas where the other rotations are used. The data given here show that with zero tillage and an integrated practice of nutrient management farmers in Haryana can maintain grain yields of wheat whilst improving quality outcomes.
  • Authors:
    • Diaz-Rossello, R.
    • Duran, H.
  • Source: Agrociencia
  • Volume: 15
  • Issue: 2
  • Year: 2011
  • Summary: Pastoral dairy farming systems in Uruguay exhibit an accelerated process of intensification with major changes in soil management during the last four decades. However, the production systems were always based on the same concept of sustainable rotations of annual forage crops and perennial grasses sown in association with legumes. The soil organic carbon (OC) in the plots of the Dairy Experimental Farm at La Estanzuela was monitored since 1974 up to 2010. Those records quantify the effect on OC dynamics of four production systems with different soil management carried out in long periods. This information is extremely relevant considering that survey studies showed that commercial dairy farming systems followed the same general pathway of technical changes. The extreme modification in tillage, animal stocking rate and feed imported to the farm determined two contrasting periods in the OC dynamics. Heavy losses of OC were estimated at an average of 0.89 Mg ha -1 year -1 during a first period of 17 years. This tendency was reversed for the following 18 years when OC increased at 0.94 Mg ha -1 year -1. Three major management factors are discussed to explain the fast build up of OC: the progressive tillage reduction, improvements in pasture and forage crop productivity and imported feed coming into the system. The large OC and N gains in semi-confinement paddocks are discussed as an opportunity to capitalize the high nutrient availability in the soil for crop production.
  • Authors:
    • dos Santos, N. Z.
    • Dieckow, J.
    • Bayer, C.
    • Molin, R.
    • Favaretto, N.
    • Pauletti, V.
    • Piva, J. T.
  • Source: Soil & Tillage Research
  • Volume: 111
  • Issue: 2
  • Year: 2011
  • Summary: To improve C sequestration in no-till soils requires further development of crop rotations with high phytomass-C additions. The objectives of this study were (i) to assess long-term (17 years) contributions of cover crop- or forage-based no-till rotations and their related shoot and root additions to the accumulation of C in bulk and in physical fractions of a subtropical Ferralsol (20-cm depth); and (ii) infer if these rotations promote C sequestration and reach an eventual C saturation level in the soil. A wheat (Triticum aestivum L., winter crop)-soybean (Glycine max (L.) Merr, summer crop) succession was the baseline system. The soil under alfalfa (Medicago sativa L, hay forage) intercropped every three years with maize (Zea mays L., summer crop) had the highest C accumulation (0.44 Mg C ha(-1) year(-1)). The bi-annual rotation of ryegrass (Lolium multiflorum Lam., hay winter forage)-maize-ryegrass-soybean had a soil C sequestration of 0.32 Mg C ha(-1) year(-1). Among the two bi-annual cover crop-based rotations, the vetch (Vicia villosa Roth, winter cover crop)-maize-wheat-soybean rotation added 7.58 Mg C ha(-1) year(-1) as shoot plus root and sequestered 0.28 Mg C ha(-1) year(-1). The counterpart grass-based rotation of oat (Avena strigosa Schreb., winter cover crop)-maize-wheat-soybean sequestered only 0.16 Mg C ha(-1) year(-1), although adding 13% more C (8.56 Mg ha(-1) year(-1)). The vetch legume-based rotation, with a relative conversion factor (RCF) of 0.147, was more efficient in converting biomass C into sequestered soil C than oat grass-based rotation (RCF = 0.057). Soil C stocks showed a close relationship (R(2) = 0.72-0.98, P < 0.10) with root C addition, a poor relationship with total C addition and no relationship with shoot C addition. This suggests a more effective role of root than shoot additions in C accumulation in this no-till soil. Most of the C accumulation took place in the mineral-associated organic matter (71-95%, in the 0-5 cm layer) compared to the particulate organic matter. The asymptotic relationship between root C addition and C stocks in bulk soil and in mineral-associated fraction supports the idea of C saturation. In conclusion, forages or legume cover crops contribute to C sequestration in no-till tropical Ferrasols, and most of this contribution is from roots and stored in the mineral-associated fraction. This combination of soil and rotations can reach an eventual soil C saturation.
  • Authors:
    • Fernandez, M. R.
    • Ulrich, D.
    • Brandt, S. A.
    • Zentner, R. P.
    • Wang, H.
    • Thomas, A. G.
    • Olfert, O.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: The impact of cropping system management on root and crown rot of spring wheat ( Triticum aestivum L.) was examined on a Dark Brown Chernozem (Typic Boroll) soil in the Canadian Prairies. This systems approach tried to reflect the most common practices of organic and conventional producers in this region. The study consisted of a factorial combination of three input levels (high, with tillage, fertilizer and pesticides; reduced [RED], with conservation tillage, targeted fertilizer and weed control; and organic [ORG] with tillage and N-fixing legumes); and three levels of cropping diversity (low diversity with wheat and summerfallow or legume green manure fallow; diversified using annual grain crops; and diversified using annual grain crops and perennial forages). All rotations were 6 yr long. Subcrown internodes and crowns/lower culms of wheat plants were scored for discoloration, and fungi in discolored tissue were identified and quantified. Overall, input level had a greater impact on disease levels and fungal frequency than cropping diversity. Discoloration severity was lowest in the RED systems, which was attributed to lower percentage isolation of Cochliobolus sativus, the most common pathogen. Fusarium species varied with input level. The pathogens F. avenaceum and F. culmorum were most associated with RED and/or least associated with ORG systems, whereas the weak pathogen/saprophyte F. equiseti was most associated with ORG systems. Thus, ORG management helped to reduce populations of F. avenaceum and F. culmorum, two of the most important Fusarium pathogens in the Canadian Prairies.
  • Authors:
    • Grebennikov, V.
    • Shipilov, I.
    • Kushch, E.
  • Source: Kormoproizvodstvo
  • Issue: 2
  • Year: 2011
  • Summary: Impacts of perennial legume-grass mixtures on regulation of soil fertility processes were studied in the Stavropol region, Russia in 2006-09. The mixtures consisted of wheat grass, sainfoin, melilot, alfalfa and bluegrass. Growth and development of roots, above-ground biomass and accumulation of organic compounds in soil were measured during the experiment. The total biomass yield of the 5-component mixture reached 9.62 t/ha at the end of the fourth year. Authors recommend this mixture for phytomelioration. The detailed data on yield dynamics of legume-grass mixtures are presented in 2 tables.
  • Authors:
    • Abusuwar, A.
    • Omer, E.
  • Source: Agriculture and Biology Journal of North America
  • Volume: 2
  • Issue: 1
  • Year: 2011
  • Summary: A field experiment was carried out for two consecutive seasons (2005/2006 and 2006/2007) in the Demonstration Farm of the Faculty of Agriculture at Shambat, University of Khartoum, Sudan, to study the effect of intercropping, phosphorus application and Rhizobium inoculation on the performance of some leguminous and cereal forage crops. The treatments used were pure stand, a mixture of Clitoria, lablab and Sudangrass, phosphorus fertilizer and Rhizobium inoculation. They were laid out in a completely randomized block design with three replications. Yield and quality were measured. Land equivalent ratio (LER) was calculated to evaluate intercropping versus monocropping. The results of the field experiment showed that, sole crop yield was higher than when grown in a mixture. The mixtures especially legume/legume combinations, gave more total forage yield than the sole crops. Nearly all the intercropping treatments had land equivalent ratio (LER) above one which indicated the advantage of intercropping over monocropping. Rhizobium inoculation and phosphorus application improved forage quality by increasing crude protein content. Intercropping and phosphorus fertilization decreased crude fiber percentage in the plant tissues.
  • Authors:
    • Ryan, J.
    • Yahyaoui, A.
    • Ahmed, S.
    • Pala, M.
  • Source: Arab Journal of Plant Protection
  • Volume: 29
  • Issue: 2
  • Year: 2011
  • Summary: Yield declines commonly observed under cereal monoculture are invariably attributed to disease buildup as well as nutrient and moisture depletions. While many long-term trials in the West Asia and North Africa region, especially in northern Syria rainfed cereal production belt, have assessed various cropping alternatives in comparison with fallow and continuous cereal cropping, few trials have involved measurement of fungal diseases. This paper reports observations made on the incidence of common root rot ( Cochliobolus sativus) from long-term trials at the International Center for Agriculture Research in the Dry Areas involving wheat and barley. With both cereals, crop rotation with legumes was shown to reduce the incidence of root rot. The results clearly indicated the need for a more comprehensive phytopathological assessment of the implications of continuous cereal cropping, especially considering the effects of residue management and nitrogen fertilization.