19862015
  • Authors:
    • Carvalho, P. C. de F.
    • Cassol, L. C.
    • Anghinoni, I.
    • Flores, J. P. C.
    • Leite, J. G. dal B.
    • Fraga, T. I.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 31
  • Issue: 4
  • Year: 2007
  • Summary: The integration of farming and cattle production activities in no-tillage system areas with winter cover crops can be an income supplement for summer grain farmers. However, many of them are afraid of adopting this integration system because of possible negative effects of animal treading on soil attributes, mainly of those related to soil compaction. This study was conducted: (1) to determine the alterations in the soil physical attributes promoted by animal treading; and (2) to verify if the alterations in soil attributes due to animal treading affect soyabean establishment and grain yield. The experiment was carried out with a Rhodic Hapludox (Oxisol), under black oat [ Avena nuda] + ryegrass [ Lolium] pasture grazed at different heights (10, 20, 30 and 40 cm) and an ungrazed area. After one cycle of animal treading, there were no significant modifications in soil bulk density, porosity and compressibility at different grazing heights. However, soil density and compressibility were higher and the porosity lower in the grazed plots. The soyabean population and grain yield were not affected by modifications in the soil physical attributes.
  • Authors:
    • Agenbag, G. A.
    • Louw, P. J. E.
    • Fourie, J. C.
  • Source: South African Journal of Enology and Viticulture
  • Volume: 28
  • Issue: 2
  • Year: 2007
  • Summary: The trial was conducted over a period of ten years (1993/94 to 2002/03) on a sandy soil in a Sauvignon blanc/Ramsey vineyard near Lutzville (31degrees35′S, 18degrees52′E), situated in the semi-arid Olifants River Valley of the Western Cape. Fourteen treatments, consisting of three grain species and four legumes, managed according to two cover crop management practices, were included. One management practice consisted of cover crops which were sown annually and full surface, post-emergence chemical control which was applied before bud break and when the berries reached pea size (BB). The second management practice consisted of cover crops which were sown biennially. Post-emergence chemical control was applied to the vine row before bud break and full surface when the berries reached pea size (AB). From 1999/2000 to 2002/03 the cover crops were sown annually, while the full surface post-emergence control applied at the end of November was advanced to mid-October. Two treatments in which Avena sativa L. v. Saia ('Saia' oats) and Vicia dasycarpa Ten. (grazing vetch) were sown annually, controlled mechanically in the work row and chemically in the vine row from bud break to harvest (MC), were also applied. These treatments were compared to a control, in which no cover crop was sown and MC was applied. A treatment in which no cover crop was sown and BB was applied (weedchem), was also included. During the third growing season of the vines (1994/95), the grapevine shoot mass of the BB treatments of grazing vetch and Medicago truncatula Gaertn. v. Paraggio ('Paraggio' medic) was significantly more than that of the AB and MC treatments, with the exception of Secale cereale L. v. Henog (AB) and grazing vetch (MC). The first harvest (1994/95) from the grapevines in the BB treatments was significantly higher than that of weedchem and the MC treatments. The grape yield of the BB treatments, grazing vetch (AB) and Ornithopus sativus L. v. Emena (pink Seradella) (AB) was significantly more than that of weedchem and the control during the 1997/98 season. The NO 3-N concentration in the leaf petioles in all the cover crop treatments was, with the exception of the AB treatments of rye, M. truncatula Gaertn. v. Parabinga ('Parabinga' medic) and grazing vetch, significantly higher than that in weedchem and the control, as measured during the 1994/95 season. The NO 3-N concentration in the leaf petioles of the BB and AB treatment of a species differed significantly. The N concentration in the juice of the cover crop treatments during the 1995/96 season was, with the exception of 'Saia' oats (MC) and 'Parabinga' medic (AB), significantly higher than that of weedchem and the control. During the 1998/99 season, the N concentration of the juice in the BB and AB treatments of grazing vetch and pink Seradella was significantly higher than that of the MC treatments, two rye treatments, weedchem and the AB treatments of the other cover crops. The concentration of Ca in the juice of the cover crop treatments was, with the exception of the pink Seradella treatments, significantly higher than that of weedchem and the control. Wine quality did not differ between treatments.
  • Authors:
    • Pereira, J.
    • Prior, M.
    • Uribe-Opazo, M.
    • Nobrega, L.
    • Lopes, R.
  • Source: Acta Scientiarum Agronomy
  • Volume: 29
  • Issue: Suplemento Espec
  • Year: 2007
  • Summary: This study evaluated alterations in the physical properties water content, soil density and porosity in areas under no tillage and tillage systems in the cultures of soybean and maize in three agricultural years. The experiment was carried out at the Experimental Nucleus of Agricultural Engineering of Unioeste (Cascavel, state of Parana). Soybean culture occurred in the first two years and in the third year maize, as summer crop, black oats and forage turnip as winter cover crops. During these three years the study observed reduction of water content and soil density and increase of porosity. The variations as regards the physical properties of the soil showed direct proportional relation between water content and soil density and was in inverse proportion for soil porosity. The soil presented improvements on its physical conditions for the porosity increase and density reduction with the black oats and forage turnip crops and maize. The soybean/maize management in rotation with black oats and forage turnip showed more adequate in the improvement of the physical conditions of the soil as compared with the management systems, since neither of the systems had a major impact in the improvements of the physical properties evaluated throughout this whole period.
  • Authors:
    • Lucca e Braccini, A.
    • Pinheiro Neto, R.
    • Lopes, R.
    • Souza, E.
  • Source: Acta Scientiarum Agronomy
  • Volume: 29
  • Issue: 4
  • Year: 2007
  • Summary: This study evaluated the performance of the soybean under the influence of vegetal covering and soil management in Red Latosol dystrofic. Oats, turnip, hairy vetch, pea, millet and lupine were used. The study evaluated height and density of plants, height of insertion in string beans, number of string beans, productivity, a thousand grain mass, water contend, bulk density and soil resistance to penetration. The no-tillage system had greater height of insertion of string beans, amount of string beans, height of plants, water contend and soil bulk density. Greater values of soil resistance to penetration were verified in the tillage, though higher productivity was observed. The coverings and the soil tillage systems influenced the productivity of soybean plants. The vegetal coverings promoted improvement of the ground with reduction of the compactation in some layers of the soil. The oats/millet association is a viable option of soil covering predecessor of soybean. The no-tillage practice showed to be the adequate management technique for the type of soil studied.
  • Authors:
    • Marshall, A.
    • Mills, A.
    • Moot, D.
    • Edwards, G.
  • Source: Proceedings of the New Zealand Grassland Association
  • Volume: 69
  • Year: 2007
  • Summary: Lucerne sown immediately or after different forage crop sequences was investigated as a pasture option for post forestry conversion. In this experiment superphosphate and lime were applied in March 2005 before final seedbed preparation and establishment of seven cropping sequences; (1) lucerne sown in April 2005; (2-5) greenfeed cereals (oats or triticale) sown in April 2005 followed by lucerne in October 2005 with or without a rape cover crop; (6-7) winter fallow followed by glyphosate presowing in October 2005 or March 2006. After all crop sequences, lucerne was successfully established and provided 100% control of woody and annual weeds. Average lucerne dry matter (DM) yield was ~7.1 t DM/ha/yr for crops after a cereal. The last crop established also contained no woody weeds but produced 10.0 t DM/ha less over the 2 years due to the long (12 month) fallow. Lucerne sown in April 2005 had to be reestablished the following October. Thus, provided soil temperatures were adequate, lucerne was successfully spring and autumn sown after plantation forests. Lucerne offers flexibility for grazing or conserving in commercial conversions where internal fences and stock water supply are often, initially, inadequate for intensive pasture management.
  • Authors:
    • Coscione, A.
    • Quaggio, J.
    • Cantarella, H.
    • Moraes, M.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 31
  • Issue: 4
  • Year: 2007
  • Summary: The efficiency of subsurface acidity alleviation by surface liming in the presence of crop residues is controversial and needs more information. The study aimed to quantify the contribution of cover crop residues, regarding their contents of low molar mass organic acids and soluble nutrients to the mobilization of reaction products of surface-applied lime in the soil profile. Two experiments were conducted under laboratory conditions using 30 cm high PVC cylinders filled with acid and clayey red latosol. Treatments consisted of sole application of lime to 80% soil base saturation (6.1 t ha -1) or lime in combination with radish ( Raphanus sativus) or black oat ( Avena strigosa) [ Avena nuda] crop residues (20 t ha -1), as well as the equivalent amounts of organic acids and inorganic salts present in the plant materials. The application of lime alone or in combination with plant material reduced soil acidity in the 0-8 cm surface layer only. The low recovery of organic acids added to the soils (≤7.2%) indicates that the acids were rapidly metabolized or adsorbed to the soil colloidal fraction, which explains the small effect on cation mobilization. A substantial part of the ion mobilization in the soil and leached solution after application of crop residues was probably due to the plant-own inorganic ion content due to the high water solubility: 65 to 71% for cations and 84% for anions. The greatest amount of aluminium displaced from the soil was due to the application of inorganic salt solutions. The presence of plant residues had little effect on the mobilization of the reaction products of surface-applied lime.
  • Authors:
    • Huang, H.
    • Blackshaw, R.
    • Mover, J.
  • Source: Canadian Journal of Plant Science
  • Volume: 87
  • Issue: 4
  • Year: 2007
  • Summary: There is a renewed interest, especially among organic growers, in using either white sweetclover ( Melilotus alba Desr.) or yellow sweetclover [ M. officinalis (L.) Lam.] as cover crops. Sweetclover cultivars and tillage practices have changed since these crops were widely used as cover crops in the first half of the 20th century. Experiments were initiated in 1999, 2000, and 2002 to compare the effect of high- and low-coumarin cultivars and crop termination methods on weed suppression, available soil N, moisture conservation and following crop yield. Weed suppression was usually more effective when sweetclover residues were left on the surface than when removed as hay. Sweetclover termination at 70% bloom was often more effective in suppressing weeds than termination at the bud stage. In the summer and fall after termination, surface residues of Yukon, a high-coumarin and drought-tolerant cultivar, reduced lamb's-quarters ( Chenopodium album L.) density by >80% compared with the no sweetclover check and essentially eliminated flixweed [ Descurainia sophia (L). Webo]. In the following spring, Yukon reduced kochia [ Kochia scoparia (L.) Schrad.] density by >80% and wild oat ( Avena fatua L.) biomass by >30% compared with the no sweetclover check. There was no difference in available N for a following crop between treatments with surface residue and cultivated fallow. Available soil moisture was about 10 mm less after the highest yielding sweetclover cultivars than after cultivated fallow, but subsequent wheat yield was not reduced. Maximum wheat yields were obtained after Yukon and Arctic sweetclover were grown as cover crops. It may be possible for organic growers to manage weeds with sweetclover in a reduced tillage system that leaves most of the plant residues on the soil surface.
  • Authors:
    • Gomezdelcampo, E.
    • Murphy, R. P.
    • Evans, J. E.
  • Source: JOURNAL OF GREAT LAKES RESEARCH
  • Volume: 33
  • Issue: SI2
  • Year: 2007
  • Summary: The Sandusky River basin, located in northwest Ohio, has been influenced by agriculture since the late-1800s. In 2003, the Ohio Environmental Protection Agency identified various tributaries of the Sandusky River as failing to meet biological water quality standards mainly due to siltation. To assess the effectiveness of best management practices (BMPs), a cutoff channel of the Sandusky River in Crawford County, Ohio was used as a unique archive of channel bed material that existed in the previous channel. Historical aerial photographs and USGS peak discharge data suggest the channel was likely abandoned between 1957 and 1964. Twelve sediment cores between 2 and 3 meters in depth were collected with a vibracore, and grain-size analyses of the cutoff channel substrate were compared to similar data collected from the modern channel. Results showed an historical fining-upward trend in the mean grain size of the coarse fraction, from gravel in the cutoff channel to sand in the modern channel, but no change in the mean grain size of the fine fraction. A series of alternative explanations were examined to elucidate this fining, including sediment storage, trends in population and crop cultivation, existence of BMPs, and sediment transport during floods. Evidence from this study strongly suggests that a shift from the cultivation of low-cover crops (hay and oats) to high-cover crops (corn and soybeans) has changed the proportion of coarse-grained to fine-grained sediment loading in this section of the Sandusky River. The results have implications both for the effectiveness of BMPs in Crawford County and possibly for Lake Erie sediment budgets.
  • Authors:
    • Castillo Gonzalez, F.
    • Perez Olvera, M. A.
    • Navarro Garza, H.
  • Source: Revista Fitotecnia Mexicana
  • Volume: 30
  • Issue: 2
  • Year: 2007
  • Summary: In this study we compared the plant coverage ability and main agronomic characteristics of five plant species in Nonoalco (2250 masl) and Ixayoc (2500 masl) in north eastern State of Mexico. The populations were: Scarlet runner bean ( Phaseolus coccineus), two faba bean varieties ( Vicia faba, var 'Purepecha' and 'V-35'), common vetch ( Vicia sativa), and oat ( Avena sativa var 'Saia'), in an experimental design in random blocks with three replications, in 6*4 m experimental plots. The scarlet runner and faba beans were planted in rows, while the vetch and oat were thrown sowed. The main variables evaluated were: percentage of area coverage and plant height, on four dates; biomass production at 70 d and at harvest, and grain yield. The results showed differences among populations in ground coverage and agronomic characteristics. Oat and vetch had the best ground cover in both sites. Oat showed the highest growth in both sites, and vetch had the second best behavior. The 'Purepecha' faba bean showed the lowest growth in both sites. The highest production of biomass for all populations in both periods, were obtained in Nonoalco because of its physical-chemical soil characteristics.
  • Authors:
    • Balkcom, K. S.
    • Gamble, B. E.
    • Patterson, M. G.
    • Reeves, D. W.
    • Price, A. J.
    • Arriaga, F. J.
    • Monks, C. D.
  • Source: Peanut Science
  • Volume: 34
  • Issue: 1
  • Year: 2007
  • Summary: Information is needed on the role of cover crops as a weed control alternative due to the increase in adoption of conservation-tillage in peanut production. Field experiments were conducted from autumn 1994 through autumn 1997 in Alabama to evaluate three winter cereal cover crops in a high-residue conservation-tillage peanut production system. Black oat ( Avena strigosa Schreb.), rye ( Secale cereale L.), and wheat ( Triticum aestivum L.) were evaluated for their weed-suppressive characteristics compared to a winter fallow system. Three herbicide systems were utilized: no herbicide, preemergence (PRE) herbicides followed by (fb) postemergence (POST) herbicides, and PRE fb sequential POST herbicides. The PRE fb POST herbicide input system consisted of pendimethalin at 1.12 kg ai/ha fb an additional early POST application of paraquat at 0.14 kg ai/ha plus bentazon at 0.56 kg ai/ha. The PRE fb sequential POST herbicide input system contained the aforementioned herbicides fb 2,4-DB at 0.22 kg ai/ha plus chlorimuron at 0.14 kg ai/ha applied late POST. No cover crop was effective in controlling weeds without a herbicide program. However, when black oat or rye was utilized with PRE fb POST herbicides, weed control was similar to the high input system in two out of three years. Yield increased in 14 of 27 comparisons following conservation-tilled peanut using the Brazilian cover crop management system, compared to a winter fallow system. Yields never decreased following a winter cover crop compared to winter fallow. The winter fallow, high herbicide input system yielded between 7 and 26% less peanut compared to the highest yielding system that included a winter cover crop. The Brazilian system using black oat or rye cover crop has potential to increase peanut productivity and reduce herbicide inputs for peanuts grown in the Southeast.