• 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:
    • Emerick, J. A. N.
    • Calazani, W. R.
    • Silva, C. F. da
    • Wendling, I. J.
    • Cunha, F. F. da
    • Araujo, R. A. S.
  • Source: Bioscience Journal
  • Volume: 27
  • Issue: 6
  • Year: 2011
  • Summary: The success in the use of pastures in silvopastoral systems depends on the understanding of the morphophysiological mechanisms and its interaction with the environment and of the management. It was aimed to evaluate the leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), emerging leaf numbers (EmLN), expanded leaf numbers (ExLN), living leaf numbers (LLN), soil cover and plant height of Marandu grass intercropped with coconut. The experiment was mounted in a completely randomized arrangement, with six replications, in a split-plot design. The plots a treatments irrigated and not-irrigated and six rest periods in the split-plots (14, 21, 28, 35, 42 and 49 days). The irrigation provided increase in the soil cover, plant height, LER and SER of Marandu grass for the rest periods of 49 and 14 days, respectively. The rest periods provided linear reduction in the LAR and SER, and linear increase in the ExLN, LLN, soil cover and plant height of Marandu grass. The LER is bigger when rest periods used of 37 and 29 days, for Marandu grass irrigated and not-irrigated, respectively. It concludes that exactly in shade conditions, Marandu grass, when irrigated and submitted the biggest rest periods, provides to greaters morphogenic taxes and growth, indicating the potential of this fodder plant in integrated systems of production.
  • Authors:
    • Dela Piccolla, C.
    • Mafra, A. L.
    • Pelissari, A.
    • de Moraes, A.
    • da Veiga, M.
    • Balbinot Junior, A. A.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha(-1) of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization (oilseed radish); and natural vegetation, without grazing and nitrogen fertilization (fallow). Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.
  • Authors:
    • Poffenbarger, H.
  • Source: Natural Sciences Education
  • Volume: 39
  • Year: 2010
  • Summary: Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops generally led to increased bulk density, especially in no-till systems. On the other hand, the negative effects of grazing on penetration resistance and aggregate stability were more prominent under conventional tillage than no-till. The deleterious effects of grazing on soil physical properties were most severe when grazing was implemented at high intensity and on wet soils. Microbial biomass C was higher under grazed conditions than ungrazed conditions. Nitrogen was found to be higher when cover crops were grazed than not grazed; however, this was only true for conventional tillage systems. Generally, grazing cover crops did not negatively affect primary crop yields. Cover crops provided nutritious forage for cattle and reduced feed costs by offsetting the use of hay or other pasture.
  • Authors:
    • Rocha, D.
    • Cano, M.
    • Patino, H.
    • Medeiros, F.
    • Gonzalez, F.
  • Source: Ciencia Rural
  • Volume: 40
  • Issue: 1
  • Year: 2010
  • Summary: The impact of energy supplementation on the performance and carcass characteristics of 24 Aberdeen-Angus * Charolais steers grazing an annual ryegrass ( Lolium multiflorum) and oat ( Avena strigosa [ Avena nuda]) pasture managed in order to avoid constrains to animal performance was evaluated. Treatments were levels of supplementation of 0, 0.4, 0.8 and 1.2% BW with a corn and mineral based supplement. Animals were slaughtered after reaching 4.5 mm of fat cover in the rump (P8) evaluated ultrasonography. No differences were observed in fat deposition, measured in live animals with ultrasound at the end of performance period, and in liveweight gain, which showed average values of 3.9 mm and 1.54 kg/day, respectively. Blood serum levels of urea were linearly decreased and cholesterol linearly increased by energy supplementation, with no differences in the serum levels of glucose and triglycerides. Energy supplementation linearly increased the killing-out proportion and carcass weight gain, but no differences were observed on the rib eye area, slaughter weight and hot carcass weight, which averaged 67.85 cm 2, 438.95 kg and 227.75 kg, respectively. Increasing the levels of supplementation resulted in higher killing-out proportion and higher carcass daily gains, without changes in performance and carcass parameters evaluated.
  • Authors:
    • Kovar, J. L.
    • Schultz, R. C.
    • Powers, W. J.
    • Russell, J. R.
    • Ahmed, S. I.
    • Mickelson, S. K.
    • Webber, D. F.
  • Source: Journal of Soil and Water Conservation
  • Volume: 65
  • Issue: 1
  • Year: 2010
  • Summary: Livestock grazing in the Midwestern United States can result in significant levels of runoff sediment and nutrient losses to surface water resources. Some of these contaminants can increase stream eutrophication and are suspected of contributing to hypoxic conditions in the Gulf of Mexico. This research quantified effects of livestock grazing management practices and vegetative filter strip buffers on runoff depth and mass losses of total solids, nitrate-nitrogen (NO3-N), and ortho-phosphorus (PO4-P) under natural hydrologic conditions. Runoff data were collected from 12 rainfall events during 2001 to 2003 at an Iowa State University research farm in central Iowa, United States. Three vegetative buffers (paddock area: vegetative buffer area ratios of 1:0.2, 1:0.1, and 1:0 no buffer [control]) and three grazing management practices (continuous, rotational, and no grazing [control]) comprised nine treatment combinations (vegetative buffer ratio/grazing management practice) replicated in three 1.35 ha (3.34 ac) plot areas. The total 4.05 ha (10.02 ac) study area also included nine 0.4 ha (1.0 ac) paddocks and 27 vegetative buffer runoff collection units distributed in a randomized complete block design. The study site was established on uneven terrain with a maximum of 15% slopes and consisted of approximately 100% cool-season smooth bromegrass. Average paddock and vegetative buffer plant tiller densities estimated during the 2003 project season were approximately 62 million and 93 million tillers ha(-1) (153 million and 230 million tillers ac(-1)), respectively. Runoff sample collection pipe leakage discovered and corrected during 2001 possibly reduced runoff depth and affected runoff contaminant mass losses data values. Consequently, 2001 runoff analysis results were limited to treatment comparisons, within the 2061 season and were not compared with 2002 and 2003 data. Analysis results from 2001 showed no significant differences in average losses of runoff, total solids, NO3-N, and PO4-P among the nine vegetative buffer/grazing practice treatment combinations. Results from 2002 indicated significantly higher losses of runoff and total solids from 1:0 no buffer/rotational grazing and 1:0 no buffer/continuous grazing treatment combination plots, respectively, compared among other 2002 season treatment combinations. The 2003 results showed significantly higher runoff and total solids losses from 1:0 no buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and from 1:0.1 vegetative buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and with respective 2002 treatment combinations. However, the 2003 results indicated effective vegetative buffer performance with significantly lower runoff, total solids, and NO3-N losses from the larger 1:0.2 buffer area compared among the smaller 1:0.1 buffer area and 1:0 no buffer treatment combinations. The 2003 results also indicated a highly significant increase in losses of NO3-N from 1:0.1 buffer/no grazing treatment combination plots compared among other 2003 season treatment combinations and with respective 2002 treatment combinations. Overall results from this study suggest a shift from significantly higher 2002 season plot losses Of Continuous and rotational grazing treatment combinations to significantly higher 2003 season losses of no grazing treatment combinations. We speculate this shift to significantly higher runoff and contaminant losses from no grazing treatment combination plots during 2003 reflects the variability inherent to a complex and dynamic soil-water environmental of livestock grazing areas. however, we also hypothesize the environmental conditions that largely consisted of a dense perennial cool-season grass type, high-relief landscape, and relatively high total rainfall depth may not necessarily include livestock grazing activities.
  • Authors:
    • Hyman, J. M.
    • Lichau, A.
    • Richardson, A.
    • Kerchner, C. D.
    • Winsten, J. R.
  • Source: Journal of Dairy Science
  • Volume: 93
  • Issue: 4
  • Year: 2010
  • Summary: This paper provides a summary of results from a recent survey of 987 dairy farmers in 4 northeastern US states. The survey results provide descriptive characteristics of the current state of dairy farming in the region, as well as farmer satisfaction levels, concerns, and plans for the future of their farming operations. The paper analyses characteristics of two increasingly important dairy production systems used in the Northeast. Averages from across the survey states (Maryland, Pennsylvania, New York, and Vermont) show that approximately 13% of dairy producers use management-intensive or rotational grazing and 7% use large, modern confinement systems with more than 300 cows. These more specialized production systems show many significant differences in farm and farmer characteristics, satisfaction levels, and plans for the future compared with farms using more traditional production systems. The changing structure of the dairy industry has potentially important implications for environmental quality, rural communities, and the food system.
  • Authors:
    • de Klein, C. A. M.
    • Grainger, C.
    • Eckard, R. J.
  • Source: Livestock Science
  • Volume: 130
  • Year: 2010
  • Authors:
    • Dalal, R. C.
    • Wang, W. J.
  • Source: Soil Solutions for a Changing World
  • Year: 2010
  • Summary: This study aimed to assess the feasibility of predicting ranges in N2O emission with a boundary line approach using a few key driving factors. Intact soil cores (9 cm dia. and ~20 cm in depth) were collected from pasture, cereal cropping and sugarcane lands and incubated at various temperature and moisture conditions after addition of different forms of mineral nitrogen (NH4+ and NO3⎯). The pasture and sugarcane soils showed greater N2O production capacity than the cropping soils with similar mineral N and organic C contents or under similar temperature and water filled pore space (WFPS%), and thus different model parameters need to be used. The N2O emission rates were classified into three ranges: low (< 16 g N2O/ha/day), medium (16 –160 g N2O/ha/day) and high (> 160 g N2O/ha/day). The results indicated that N2O emissions were in the low range when soil mineral N content was below 10 mg N/kg for the cropping soils and below 2 mg N/kg for the pasture and sugarcane soils. In soils with mineral N content exceeding the above thresholds, the emission rates were largely regulated by soil temperature and WFPS and the emission ranges could be estimated using linear boundary line models that incorporated both temperature and WFPS. Using these key driving factors (land use, temperature, WFPS and mineral N content), the boundary line models correctly estimated the emission ranges for 85% of the 247 data points for the cropping soils and 59% of the 271 data points for the pasture and sugarcane soils. In view of the fact that N2O emissions from soil are often very variable and difficult to predict and that the soil and environmental conditions applied in this study differed substantially, the above results suggested that, in terms of accuracy and feasibility, the boundary line approach provides a simple and practical alternative to the use of a single emission factor and more complex process-based models.
  • Authors:
    • Bryan, B. A.
    • King, D.
    • Wang, E.
  • Source: Global Change Biology Bioenergy
  • Volume: 2
  • Issue: 6
  • Year: 2010
  • Summary: First-generation biofuels are an existing, scalable form of renewable energy of the type urgently required to mitigate climate change. In this study, we assessed the potential benefits, costs, and trade-offs associated with biofuels agriculture to inform bioenergy policy. We assessed different climate change and carbon subsidy scenarios in an 11.9 million ha (5.48 million ha arable) region in southern Australia. We modeled the spatial distribution of agricultural production, full life-cycle net greenhouse gas (GHG) emissions and net energy, and economic profitability for both food agriculture (wheat, legumes, sheep rotation) and biofuels agriculture (wheat, canola rotation for ethanol/biodiesel production). The costs, benefits, and trade-offs associated with biofuels agriculture varied geographically, with climate change, and with the level of carbon subsidy. Below we describe the results in general and provide (in parentheses) illustrative results under historical mean climate and a carbon subsidy of A$20 t−1 CO2−e. Biofuels agriculture was more profitable over an extensive area (2.85 million ha) of the most productive arable land and produced large quantities of biofuels (1.7 GL yr−1). Biofuels agriculture substantially increased economic profit (145.8 million $A yr−1 or 30%), but had only a modest net GHG abatement (−2.57 million t CO2−e yr−1), and a negligible effect on net energy production (−0.11 PJ yr−1). However, food production was considerably reduced in terms of grain (−3.04 million t yr−1) and sheep meat (−1.89 million head yr−1). Wool fiber production was also substantially reduced (−23.19 kt yr−1). While biofuels agriculture can produce short-term benefits, it also has costs, and the vulnerability of biofuels to climatic warming and drying renders it a myopic strategy. Nonetheless, in some areas the profitability of biofuels agriculture is robust to variation in climate and level of carbon subsidy and these areas may form part of a long-term diversified mix of land-use solutions to climate change if trade-offs can be managed.