• Authors:
    • Venterea, Rodney T.
    • Baker, John M.
    • Griffis, T. J.
    • Bavin, T. K.
    • Batjes, Niels
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 134
  • Issue: 3
  • Year: 2009
  • Summary: Agricultural ecosystems have been viewed with the potential to sequester atmospheric carbon dioxide (CO2) by increasing soil organic carbon (SOC) through reduced tillage and cover cropping practices. There remains considerable uncertainty, however, regarding the carbon (C) sink/source potential of these systems and few studies have examined C dynamics in conjunction with other important greenhouse gases. The objective of this study was to evaluate the impact of an alternative management scenario (reduced tillage and cover cropping) on ecosystem respiration (RE) and nitrous oxide (N2O) and methane (CH4) fluxes in a maize (Zea mays L.)/soybean (Glycine max L) rotation ecosystem in east-central Minnesota, United States. The control treatment was managed using fall tillage with a chisel plow in combination with a tandem disk, and the experimental treatment was managed using strip tillage and a winter rye (Secal cereale) cover crop. Over the two-year study period (2004-2005), cumulative RE was 222.7 g C m(-2) higher in the alternatively managed treatment as a result of increased decomposition of the cover crop residue. N2O fluxes were similar in both treatments during the 2004 growing season and were 100.1 mg N m(-2) higher in the conventional treatment during the 2005 growing season after nitrogen (N) fertilization. N fertilization and fertilizer type were the dominant factors controlling N2O fluxes in both treatments. CH4 fluxes were negligible in both treatments and often below the detection limit. Cumulative growing season N2O losses in the control and experimental treatments, which totalled 38.9 +/- 3.1 and 26.1 +/- 1.7 g C m(-2) when converted to CO2 equivalents, were comparable to the annual estimates of net ecosystem CO2 exchange in both treatments. This study further supports that N2O losses are an important component of the total greenhouse gas budget of agroecosystems. It also suggests that spring cover cropping, without residue removal, has limited C sequestration potential. The results from this study, however, may not necessarily represent equilibrium conditions in the experimental treatment. Rather, they are a measure of the transient response of the system after tillage conversion and cover crop addition. It is expected that the soil microbes will continue to adjust to the reduction in tillage and increased C inputs. Therefore, continued, long-term monitoring is needed to confirm whether the results are representative of equilibrium conditions. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Zibilske, L.
    • Makus, D.
  • Source: Geoderma
  • Volume: 149
  • Issue: 3/4
  • Year: 2009
  • Summary: Management of a black oat ( Avena strigosa [Schreb.]) cover crop by mowing method (none, flail mowing, or sickle bar mowing) affected soil micro environmental conditions and soil microbial and chemical properties. Soil temperatures at depths of 0, 5, 10 and 20 cm were highest in flail mowed treatment plots (up to near 45°C at 5 cm depth), followed by sickle bar mowed plots (averaging 10°C lower at 5 cm depth). Lowest soil temperatures were maintained in plots that were not mowed; averaging 5°C lower at 5 cm depth than the sickle bar mowed plots. Increasing temperature convergence was observed below 5 cm, with the highest temperature (flail mowed treatment) at 32°C and the lowest (not mowed) at 27°C. Microbial biomass increased significantly ( P150 mg C kg -1 in the early fall. beta-glucosidase and alkaline phosphatase activities decreased slowly throughout the experiment, and were significantly greater ( P
  • Authors:
    • Azevedo, W.
    • Pereira, H.
    • Reis, E.
    • Souza, E.
    • Carneiro, M.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 33
  • Issue: 1
  • Year: 2009
  • Summary: This study investigated the effects of tillage systems and soil use on the physical, chemical and biological properties of a clayey dystrophic Red Latosol (Oxisol) and a sandy Neosol (Entisol). The treatments for the Oxisol consisted of: native savanna, pasture, conventional tillage, no-tillage with turnip and with forage sorghum as cover crop. For the Entisol: native savanna, native pasture, integrated crop-livestock, cultivated pasture, no-tillage with soyabean and maize in the summer. Soil samples were collected from a depth of 0-10 cm, in a clayey dystrophic Oxisol and a sandy Entisol in a savanna ecosystem, near the Parque Nacional das Emas in Goias, Brazil. Treatments were arranged in a completely randomized design, in 5 plots of 150 m 2, where 10 sub-samples were collected randomly. Chemical, physical and biological analyses were carried out at a soil laboratory. In the Entisol, tillage influenced the soil density, total pore volume, macroporosity and penetration resistance. In the Oxisol, tillage induced variations in soil bulk density, macroporosity and penetration resistance. Small variations in chemical properties were observed in both soils, with higher potential acidity and lower exchangeable cation and phosphorus concentrations. The soil biological properties were influenced by tillage, and were most affected in systems with more anthropic action. In the canonical data analysis the greater weighting coefficient of the physical properties in the canonic variables demonstrated that these were the least important. The contribution of the separate soil properties to evaluate soil quality was minor, but the most sustainable management systems could be defined by multivariate analysis.
  • Authors:
    • Florio, G.
    • Brigi, A.
    • Sandrini, S.
    • Bona, S.
    • Coletto, L.
    • Sambo, P.
  • Source: Proceedings of the Conference on integrated assessment of agriculture and sustainable development: Setting the Agenda for Science and Policy (AgSAP 2009), Hotel Zuiderduin, Egmond aan Zee, The Netherlands, 10-12 March 2009
  • Year: 2009
  • Authors:
    • Diaz-Zorita, M.
    • Pena-Yewtukhiw, E.
    • Grove, J.
    • Blevins, R.
  • Source: Better Crops with Plant Food
  • Volume: 93
  • Issue: 4
  • Year: 2009
  • Summary: This long-term Kentucky study evaluated the impact of tillage and N rates on crop yield and soil organic matter (SOM). After 29 years of continuous corn with a winter cereal cover crop, the combination of no-till cropping and fertilizer N use resulted in SOM levels similar to those in adjacent grass sod. There was no evidence that fertilizer N caused SOM loss.
  • Authors:
    • Garcia, R.
    • Dornelles, M.
    • Lima, A.
    • Coelho, F.
    • Lima, E.
  • Source: Revista Ceres
  • Volume: 56
  • Issue: 6
  • Year: 2009
  • Summary: The objective of this work was to evaluate a number of soybean agronomic characteristics in green manuring succession with two types of residue management. An experiment arranged in a complete randomized block design with four repetitions distributed in a split-plot scheme was carried out in Campos dos Goytacazes-RJ, in the agricultural year 2001/2002. The plots consisted of two managements (with and without clipping) and the subplots consisted of the cover species (black oat, millet, forage sorghum, teosinte, forage radish, dwarf velvet bean, white lupin, pigeonpea, and spontaneous vegetation). In the treatment without clipping, the mean grain yield of soybean in succession with black oat and spontaneous vegetation was 50% higher than the succession with dwarf velvet bean, millet, pigeonpea and forage sorghum. However, in the treatment with clipping, the mean grain yield in succession with millet, teosinte and spontaneous vegetation was 79% higher than the succession with lupin and dwarf velvet bean. The management of millet with mechanical clipping resulted in the increase of 1.154 kg ha -1 of soybean compared wih the treatment without management.
  • Authors:
    • Nakagawa, J.
    • Cavariani, C.
    • Crusciol, C.
    • Lima, E.
  • Source: Revista Brasileira de Sementes
  • Volume: 31
  • Issue: 1
  • Year: 2009
  • Summary: Soybean productivity under the no till system (NTS) can be influenced by the preceding type of plant cover and surface liming. However, the effects of this technique on yield components and the seed physiological quality have been little studied, especially in ("safrinha") off-season soybean under NTS. Therefore, this study aimed to evaluate some agronomic traits, yield components, productivity, and physiological quality of soybean grown during the off-season ("safrinha"), as a function of different cover plants, with or without surface liming, under NTS. The experiment was conducted during the 1999/00 cropping season on the Lageado Experimental Farm, FCA/UNESP/Botucatu-SP, Brazil. The experimental design was organized as randomized blocks in split-plots, with 4 replications. The 6 m * 10 m plots consisted of broomcorn ( Sorghum bicolor), millet ( Pennisetum americanum), fall panicum ( Panicum dichotomiflorum), spontaneous vegetation, and no vegetation. At 53 days after emergence the cover plants were desiccated and lodged, and a surface application of 3.1 t.ha-1 lime was made in half of the plots, in order to increase V% to 70. Soybean (cv. IAC-19) was sown two weeks later, during the off-season ("safrinha"). Determinations were made for the final stand, first pod height, plant height, total number of pods and blank pods per plant, total number of seeds per pod, 100-seed weight and yield. As to seed physiological quality, determinations were made for germination, artificial aging, germination at 18C, plantlet D.M., and electric conductivity. During NTS implementation, plant cover type and surface liming did not affect the agronomic traits studied, yield components, seed productivity, and physiological quality of soybean seeds grown in the off-season ("safrinha") system, except for electric conductivity.
  • Authors:
    • Cargnelutti Filho, A.
    • Assis, R.
    • Procopio, S.
    • Monteiro, F.
    • Pires, F.
    • Pacheco, L.
    • Carmo, M.
    • Petter, F.
  • Source: Planta Daninha
  • Volume: 27
  • Issue: 3
  • Year: 2009
  • Summary: The objective of this experiment was to evaluate the efficiency of soybean oversowing, using cover crops, in reducing weed emergence and its reflections on the productivity of the soybean cultivated in the following season. The experiment was arranged in a randomized block design, in split-plot, with four replications. The soybean was sown four times: (1) 10/27/2005, (2) 11/10/2005, (3) 11/24/2005 and (4) 12/14/2005, under a no-tillage system, corresponding to four times of soybean oversowing, occurring respectively, on 01/30/2006; (b) 02/13/2006; (c) 02/22/2006; and (d) 03/14/2006. Six cover crops were evaluated [ Brachiaria brizantha, B. ruziziensis, B. decumbes, Eleusine coracana, Pennisetum glaucum and cover crop-sorghum hybrid ( Sorghum bicolor cv. Bicolor) with Sudan-grass ( Sorghum bicolor cv. Sudanense)] and untreated (spontaneous vegetation) in four oversowing times. Oversowing was performed manually when the soybean reached the R 7 stadium (beginning of defoliation during physiological maturation), in each of the four sowing times of the 2005/06 soybean crop. The first cover crop desiccation was carried oat on 10/23/2006. After 20 days, the second desiccation was applied, followed by soybean sowing, cultivar MSOY 6101, early cycle, 0.45 m spaced, aimed at a population of 500.000 plants ha -1. Soybean oversowing, especially when using brachiaria, showed to be an important tool for the integrated management of weed plants, since it provides a larger biomass contribution and soil cover and sustainability to no-till systems in the cerrado.
  • Authors:
    • Balasubramanian, V.
    • Kumar, A.
    • Prabhu, M.
    • Jagadeesan, R.
  • Source: Asian Journal of Horticulture
  • Volume: 4
  • Issue: 1
  • Year: 2009
  • Summary: This review discusses the various cropping systems (multiple cropping, intercropping and cover cropping) that are successfully adopted for some tropical vegetables in India, including a few tuber vegetables. The role of cropping systems in crop protection (specifically the management of diamond back moth [ Plutella xylostella] in cabbage using collard as a trap crop, use of maize as an intercrop to control a viral disease of pepper, reduction of the incidence of bacterial wilt caused by Pseudomonas solanacearum [ Ralstonia solanacearum] in tomato by intercropping, and use of French marigold [ Tagetes patula] as a trap crop for the control of Meloidogyne incognita on potato) is briefly discussed.
  • Authors:
    • Oliveira, E.
    • Baliza, D.
    • Rodrigues, T.
    • Avila, F.
    • Faquin, V.
    • Rodrigues, C.
  • Source: CIENCIA E AGROTECNOLOGIA
  • Volume: 33
  • Issue: 6
  • Year: 2009
  • Summary: This study investigated the effect of the previous cultivation of different forage grasses fertilized with triple superphosphate (TSP) and reactive Arad phosphate (RAP) on growth, yield, and accumulation of P by soyabean. Two experiments were carried out: one in Haplic Cambisol typical distrophic, medium texture and the other in Red Latosol typical distrophic very clayey texture. For both experiments, the experimental design was a completely randomized one in a 4*2*2 factorial scheme; the previous crop being of four forage grasses utilized as cover plants in no-tillage system ( Brachiaria decumbens [Urochloa decumbens], Brachiaria brizantha [U. brizantha], millet and forage sorghum) fertilized with two sources of P (RAP and TSP) and two additional treatments, which are the cultivation of soyabean and bean plant without the previous growing of cover plants, and also fertilized with TSP and RAP. The plants were harvested after they had completed the development cycle. Grain and shoot dry matter yield and P accumulation in the shoot and in the grains of soyabean were determined. The forage plants immobilized the P of TSP, reducing the residual effect for soyabean. When forage grasses are fertilized with RAP, there is increased residual effect with increasing yield of soyabean in succession to the cover plants, with exception for the growing in succession to B. brizantha.