• Authors:
    • Strickland, T. C.
    • Bosch, D. D.
    • Webster, T. M.
    • Truman, C. C.
    • Potter, T. L.
  • Source: Journal of Agricultural and Food Chemistry
  • Volume: 59
  • Issue: 14
  • Year: 2011
  • Summary: Intensive glyphosate use has contributed to the evolution and occurrence of glyphosate-resistant weeds that threaten production of many crops. Sustained use of this highly valued herbicide requires rotation and/or substitution of herbicides with different modes of action. Cotton growers have shown considerable interest in the protoporphyrinogen oxidase inhibitor, fomesafen. Following registration for cotton in 2008, use has increased rapidly. Environmental fate data in major use areas are needed to appropriately evaluate risks. Field-based rainfall simulation was used to evaluate fomesafen runoff potential with and without irrigation incorporation in a conventional tillage system (CT) and when conservation tillage (CsT) was practiced with and without cover crop residue rolling. Without irrigation incorporation, relatively high runoff, about 5% of applied, was measured from the CT system, indicating that this compound may present a runoff risk. Runoff was reduced by >50% when the herbicide was irrigation incorporated after application or when used with a CsT system. Data indicate that these practices should be implemented whenever possible to reduce fomesafen runoff risk. Results also raised concerns about leaching and potential groundwater contamination and crop injury due to rapid washoff from cover crop residues in CsT systems. Further work is needed to address these concerns.
  • Authors:
    • Passos, A. M. A. dos
    • Albuquerque, A. de
    • Resende, P. M. de
    • Baliza, D. P.
    • Reis, W. P.
    • Botrel, E. P.
  • Source: Revista de Agricultura
  • Volume: 86
  • Issue: 1
  • Year: 2011
  • Summary: The objective of this work was to compare the potential of the irrigated wheat under no tillage and conventional cropping systems, as well as to evaluate the performance of fifteen wheat cultivars in the two cropping systems, in succession to soybean crop, in the South of Minas Gerais. The experiment was carried out in the Federal University of Lavras (UFLA), in Lavras, MG, in the years of 2006/07 and 2007/08, in a split-block-designed scheme in a randomized complete block design, with three replications. The cropping systems (conventional and no-tillage) were installed in the rows and, in the columns, the fifteen wheat cultivars were distributed. The wheat yield and others agronomic characteristics were evaluated. The no-tillage provided an average increase of 25% in the organic matter levels in the topsoil layer in relation to previous levels and to conventional cropping system. The cultivars tested, independent of the agricultural year, significantly altered the grain yields and the agronomic characteristics. The high yield presented by the cultivars evaluated in this study indicates the high potential of the irrigated wheat cropped in succession to soybean crops, under similar climatic and soil conditions used in this study.
  • Authors:
    • Mauli, M. M.
    • de Lima, G. P.
    • Pereira Nóbrega, L. H.
    • Rosa, D. M.
  • Source: Semina: Ciências Agrárias (Londrina)
  • Volume: 32
  • Issue: 4
  • Year: 2011
  • Summary: The no-tillage system management is considered as an agricultural system very close to sustainability, since it causes less impact to the environment. The crops rotation, when well managed, includes the use of green manure; and leguminous are included in this system as they bring a number of benefits. This context, the study aimed tested leguminous as cover plants on soil with a no-tillage system regarding the growth, yield and maize seeds quality. This decision-making looks for alternatives that contribute for the agroecosystem sustainability, since they allow rational adoption of green manure in production units. The experiment was carried out in the field with leguminous species dwarf mucuna beans, dwarf pigeon pea and stylosanthes, sown in October 2007, in 4 x 5 m plots, with five replications. At 90 days after the cover crops sowing, the leguminous plants were grazed and corn plants were sown 15 days after grazing on waste. The plants heights were determined during the culture development. At the laboratory, after harvest, the productivity and physiological quality of seeds were determined. The experimental design was completely randomized and the averages were compared by the Scott-Knott test at 5% of significance. At 60 days after the maize crop sowing, the treatments with dwarf mucuna beans and dwarf pigeon pea showed higher heights. The other analyzed parameters did not differ among themselves, showing that the treatments not interfere on the maize crop. Actually, it is an alternative to the integrated management of species concerning the summer green manure and crop rotation in no-tillage system.
  • Authors:
    • Armengot, L.
    • Berner, A.
    • Sans, F. X.
    • Maeder, P.
  • Source: Weed Research
  • Volume: 51
  • Issue: 4
  • Year: 2011
  • Summary: Conservation tillage could provide environmental benefits to organic farming. However, potential weed problems often tend to discourage farmers from adopting it. The effects of tillage (reduced vs. conventional), fertilisation (slurry vs. manure compost) and the application of biodynamic preparations (with and without) on crop yield and on weed cover, diversity and biological attributes were investigated in a cropping sequence of wheat, sunflower and spelt. Total weed cover and perennial cover in reduced tillage treatments were two to three times greater than in conventional treatments. Monocotyledon cover in reduced tillage was three times that in conventional tillage in spelt, whereas the dicotyledon Stellaria media dominated in sunflower. Weed diversity was similar across treatments, regardless of cereal crop, whereas lower diversity values were observed with reduced tillage in sunflower, because of the dominance of S. media. There was virtually no effect of fertilisation and biodynamic preparations on weed parameters. Although wheat and spelt yield decreased in reduced tillage plots (14% and 8% respectively), the sunflower grain yield was unaffected. Reduced tillage could thus be useful in organic cropping systems but would require proper management of perennial and monocotyledonous weeds, which are often problematic for annual crops.
  • Authors:
    • Armstrong, S. D.
    • Hernandez-Ramirez, G.
    • Smith, D. R.
    • Bucholtz, D. L.
    • Stott, D. E.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 3
  • Year: 2011
  • Summary: Recent efforts have attempted to establish emission estimates for greenhouse gas (GHGs) from agricultural soils in the United States. This research project was conducted to assess the influence of cropping system management on non-CO(2) GHG emissions from an eastern Corn Belt Alfisol. Corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotation plots were established, as were plots in continuous management of native grasses or sorghum-sudan-grass [Sorghum bicolor (L.) Moench nothossp. drummondii (Steud.) de Wet ex Davidse]. Greenhouse gas fluxes were monitored throughout each growing season from 2004 through 2007. Fluxes of N(2)O were significantly correlated with soil temperature (P
  • Authors:
    • LaFond, G. P.
    • May, W. E.
    • Tenuta, M.
    • Entz, M. H.
    • Turmel, M. S.
  • Source: Canadian Journal of Plant Science
  • Volume: 91
  • Issue: 6
  • Year: 2011
  • Summary: Leguminous cover crops are becoming a popular way to increase the sustainability of agricultural systems. Previously, cover crops have been found to increase colonization by arbuscular mycorrhizal fungi (AM F) and phosphorus and micronutrient uptake. Long-term field studies were conducted to test the hypothesis that self-regenerating black medic (Medicago lupulina cv. George) cover crops increase AM F colonization and early nutrient uptake in flax (Linum usitatissimum). Field experiments were established in 2000 (Manitoba) and 2002 (Saskatchewan) using a flax wheat (Triticum aestivum) oat (Avena sativa) rotation. In a second experiment, intact soil cores were harvested from the plots in spring and tested for soil disturbance and cover crop effects under controlled environment conditions (CEC). Both seedling flax crops sampled from the field in 2005 and 2006 and flax growth in CEC showed high levels of AMF root colonization, but no significant influence of the cover crop on AM F colonization by arbuscules or hyphal structures was detected. The AMF enhancing practices used in the experiments (i.e., zero-tillage and inclusion of mycorrhizal crops) may have contributed to the lack of cover crop effect on AMF colonization. The cover crop had no effect on macro- or micronutrient uptake by flax except during drought conditions (Winnipeg 2006), where flax biomass was reduced by 38% and the total uptake of N, P, Zn and Cu was decreased by 34, 30, 31 and 35%, respectively, in the medic treatment.
  • Authors:
    • Pulrolnik, K.
    • Marchão, R. L.
    • Guimarães Junior, R.
    • Motta Macedo, M. C.
    • Martha Junior, G. B.
    • Vilela, L.
    • Maciel, G. A.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to analyze the benefits and the potential prospects of integrated crop-livestock systems in the process of crop and pasture intensification in the Cerrado, and to point out the main information gaps about the system. The main benefits of crop-livestock integration are: improved chemical, physical and biological properties of the soil; reduction of diseases, pests and weed outbreaks occurrence; higher crop and animal productivity; and risk reduction due to diversification of activities. However, the adoption of the crop-livestock system is still low, probably due to the greater complexity of the system. Concentrating efforts on the factors that limit the system's adoption is strategic for new studies. The search for better soil cover for the no tillage system, through forage grasses, can boost the adoption of integrated crop-livestock in the Cerrado. It is expected that the adoption of integrated crop-livestock systems improve the socioeconomic and environmental sustainability of the farm and of its region of influence.
  • Authors:
    • Gomez-Macpherson, H.
    • Mateos, L.
    • Boulal, H.
  • Source: Irrigation Science
  • Volume: 29
  • Issue: 5
  • Year: 2011
  • Summary: Zero tillage and controlled traffic have been proposed as means for more productive and sustainable irrigated farming. Both practices affect soil infiltration characteristics and, therefore, should have effects on sprinkler irrigation performance. This study compared water infiltration and runoff in three sprinkler irrigation tests performed on an alluvial loam soil at different times during a maize (Zea mays L.)-cotton (Gossypium hirstium L.) rotation under two soil managements: permanent beds with crop residue retention (PB: planting beds maintained unaltered from year to year) and conventional beds with residues incorporated with tillage (CB: disc and chisel ploughing followed by rotavator pass and bed forming every year). Traffic was controlled and two types of furrows were distinguished in both tillage systems: with (+T) and without (-T) wheel traffic. The irrigation tests were performed on maize at full cover, on bare soil just before cotton sowing and on cotton with 50% ground cover. Infiltration and runoff were affected notably by both traffic and soil management. The soil under PB infiltrated more water than under CB, and -T furrows more than +T furrows. Considering the combined treatments, -T furrows in the CB system infiltrated more water than +T furrows in the PB system. A sprinkler irrigation model for simulating water application and soil infiltration and runoff was formulated. The model was used to analyse irrigation performance under infiltration characteristic of the CB and PB systems in trafficked and non-trafficked furrows. Five irrigation performance indicators were used to assess the various combinations of tillage and traffic: Wilkox-Swailes coefficient of uniformity; application efficiency; deep percolation ratio; tail water ratio; and adequacy. The model was used to develop operation diagrams and provided guidelines for making irrigation decisions in the new controlled traffic/permanent bed system and in a standard conventional system.
  • Authors:
    • Maldaner, G. L.
    • Spera, S. T.
    • Fontaneli, R. S.
    • dos Santos, H. P.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to assess energy conversion and balance of integrated crop-livestock production systems, under no-tillage. The experiment was carried out from 2001 to 2008. From 2001 to 2002, the following systems were evaluated: 1, wheat/soybean, and black oat pasture+common vetch/corn; 2, wheat/soybean, and black oat pasture+common vetch+ryegrass/corn; 3, wheat/soybean and black oat pasture+common vetch/millet pasture; 4, wheat/soybean and black oat pasture+common vetch+rygrass/millet pasture; 5, wheat/soybean, white oat/soybean, and black oat pasture+common vetch/millet pasture; 6, wheat/soybean, white oat/soybean, and black oat pasture+common vetch+rygrass/millet pasture. From 2003 to 2008, the following systems were evaluated: 1, wheat/soybean, and common vetch/corn; 2, wheat/soybean, and black oat pasture/corn; 3, wheat/soybean, and black oat pasture/soybean; 4, wheat/soybean, and field pea/corn; 5, wheat/soybean, common vetch/soybean, and double purpose triticale/soybean; and 6, wheat/soybean, double purpose white oat/soybean, and double purpose wheat/soybean. Corn showed highest returned energy in comparison to the other grain crops, and to winter and summer annual pastures. Of the winter cover crops and green manure species evaluated, field pea was the most efficient in energy conversion. Systems 1, 2, and 4, from 2003 to 2008, had the most efficient energy balance.
  • Authors:
    • Kumar, V.
    • Kumar, V.
    • Saharawat, Y. S.
    • Ladha, J. K.
    • Gathala, M. K.
    • Sharma, P. K.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 5
  • Year: 2011
  • Summary: Rice-wheat (Oryza sativa L.-Triticum aestivum L.) rotation is the major production system in Asia, covering about 18 million ha. Conventional practice of growing rice (puddled transplanting) and wheat (conventional till, CT) deteriorate soil physical properties, and are input- and energy-intensive. Zero-tillage (ZT) along with drill-seeding have been promoted to overcome these problems. A 7-yr permanent plot study evaluated various tillage and crop establishment (CE) methods on soil physical properties with an aim to improve soil health and resource-use efficiency. Treatments included transplanting and direct-seeding of rice on flat and raised beds with or without tillage followed by wheat in CT and ZT soil. Bulk density (D(b)) of the 10- to 20-cm soil layer was highest under puddled treatments (1.74-1.77 Mg m(-3)) and lowest under ZT treatments (1.66-1.71 Mg m(-3)). Likewise, soil penetration resistance (SPR) was highest at the 20-cm depth in puddled treatments (3.46-3.72 MPa) and lowest in ZT treatments (2.51-2.82 MPa). Compared with conventional practice, on average, water-stable aggregates (WSAs) > 0.25 mm were 28% higher in ZT direct-seeding with positive time trend of 4.02% yr(-1). Infiltration was higher (0.29-0.40 cm h(-1)) in ZT treatments than puddled treatments (0.18 cm h(-1)). The least-limiting water range was about double in ZT direct-seeding than that of conventional practice. Gradual improvement in soil physical parameters in ZT system resulted in improvement in wheat yield and is expected to be superior in long-run on system (rice+wheat) basis. Further research is needed to understand mechanisms and requirements of two cereals with contrasting edaphic requirements in their new environment of ZT direct-seeding.