31. Influence of ley duration on the yield and quality of the subsequent cereal crop (spring oats) in an organically managed long-term crop rotation experiment.

• Authors:
  • Topp, C.
  • Walker, R.
  • Rees, R.
  • Edwards, A.
  • Baddeley, J.
  • Watson, C.
• Source: Organic Agriculture
• Volume: 1
• Issue: 3
• Year: 2011
• Summary: The ability to maintain crop yield and quality in systems based on nitrogen (N) fixed by legumes rather than from synthetic N fertilisers is fundamental to the long-term viability of organic farming. This paper reports crop yield and nitrogen uptake parameters for the first spring oat crop after grass/clover ley in organically managed ley/arable rotations to indicate the amount of fertility built-up during the ley period. The trial site, at Tulloch in North East Scotland, underwent two complete cycles of 6-year ley/arable rotations with different lengths of grazed ley (3 or 4 years). Trials were sufficiently replicated so that each course of the rotation was present in every year. The rotation containing 3 years of ley was also compared with a similar rotation at a nearby site (Woodside) with lower rainfall and soil fertility over one and a half rotational cycles. Grain yields were consistently higher at Tulloch (5.1 tha -1 compared with 4.5 tha -1 at Woodside) and were unaffected by the length of ley. However, grain N percentage was higher following the 4-year ley (1.38% compared with 1.30% following the 3-year ley). While yields were maintained between the first and second cycles of all the rotations, grain N percentage declined. Annual grain yields of the organically grown oats at Tulloch were not significantly different from National List/Recommended List yields in NE Scotland for oats receiving 100 kg N ha -1. Results suggest that these particular rotation designs were suitable for maintaining acceptable grain yields under organic management conditions.

32. Soil organic carbon and total nitrogen under Leucaena leucocephala pastures in Queensland

• Authors:
  • Shelton, H. M.
  • Radrizzani, A.
  • Kirchhof, G.
  • Dalzell, S. A.
• Source: Crop and Pasture Science
• Volume: 62
• Issue: 4
• Year: 2011
• Summary: Soil organic carbon (OC) and total nitrogen (TN) accumulation in the top 0–0.15 m of leucaena–grass pastures were compared with native pastures and with continuously cropped land. OC and TN levels were highest under long-term leucaena–grass pasture (P < 0.05). For leucaena–grass pastures that had been established for 20, 31, and 38 years, OC accumulated at rates that exceeded those of the adjacent native grass pasture by 267, 140, and 79 kg/ha.year, respectively, while TN accumulated at rates that exceeded those of the native grass pastures by 16.7, 10.8, and 14.0 kg/ha.year, respectively. At a site where 14-year-old leucaena–grass pasture was adjacent to continuously cropped land, there were benefits in OC accumulation of 762 kg/ha.year and in TN accumulation of 61.9 kg/ha.year associated with the establishment of leucaena–grass pastures. Similar C : N ratios (range 12.7–14.5) of soil OC in leucaena and grass-only pastures indicated that plant-available N limited soil OC accumulation in pure grass swards. Higher OC accumulation occurred near leucaena hedgerows than in the middle of the inter-row in most leucaena–grass pastures. Rates of C sequestration were compared with simple models of greenhouse gas (GHG) emissions from the grazed pastures. The amount of carbon dioxide equivalent (CO2-e) accumulated in additional topsoil OC of leucaena–grass pastures ≤20 years old offset estimates of the amount of CO2-e emitted in methane and nitrous oxide from beef cattle grazing these pastures, thus giving positive GHG balances. Less productive, aging leucaena pastures >20 years old had negative GHG balances; lower additional topsoil OC accumulation rates compared with native grass pastures failed to offset animal emissions

33. Carbon sequestration and biodiversity restoration potential of semi-arid mulga lands of Australia interpreted from long-term grazing exclosures

• Authors:
  • Bird, M. I.
  • Beeton, R. J. S.
  • Menzies, N. W.
  • Witt, G. B.
  • Noel, M. V.
• Source: Agriculture, Ecosystems & Environment
• Volume: 141
• Issue: 1-2
• Year: 2011

34. Modelling and mapping agricultural opportunity costs to guide landscape planning for natural resource management.

• Authors:
  • Ward, J.
  • King, D.
  • Bryan, B.
• Source: Ecological Indicators
• Volume: 11
• Issue: 1
• Year: 2011
• Summary: On-farm actions to better manage natural resources often involve an opportunity cost associated with foregone agricultural production. Spatial information on agricultural opportunity costs is a key indicator that has been demonstrated to increase the cost-effectiveness of environmental investment through spatial targeting. In this paper we develop a method for calculating expected profit as a more robust spatial measure of economic rent accruing from agricultural land and indicator of opportunity cost for use in landscape and planning for natural resource management. We apply this method to the Lower Murray region in southern Australia. Agricultural profit is calculated for three farming system phases (cereals, legumes, and grazing) by census zones based on agricultural statistics and cost of production information within a GIS environment. Zonal profit layers are smoothed using pycnophylactic (mass preserving) interpolation. Farming system rotations are quantified as a set of continuous spatial probability layers for each phase using a moving window kernel density technique based on existing land use data and these probability layers are used in a weighted allocation of expected profit across the landscape. The expected profit layer provides a high spatial resolution description of opportunity costs associated with natural resource management over the Lower Murray region suitable for input into systematic landscape planning analyses. Validation of the opportunity cost layer by field survey identified both random and systematic error. Interpretation of systematic error highlighted the need to augment pycnophylactic interpolation techniques with consideration of covariates of profit such as rainfall for better estimation in areas with high profit gradients.

35. Types of organic production in the Lower Silesia.; Rodzaje produkcji ekologicznej na Dolnym Slasku.

• Authors:
  • Golinowska, M.
• Source: Journal of Research and Applications in Agricultural Engineering
• Volume: 56
• Issue: 3
• Year: 2011
• Summary: In early 2010, in Lower Silesia, there were 1,025 organic farms, including 47% of households had a status of "inconversion". Most of them, up to 23% of organic farms were located in the county Kodzko and 16% in the district of Wroclaw. The diversity of organic farms in various districts of Lower Silesia was high and ranged from 1 (Strzelin district) to 235 (Kodzko district). Lot of factors had an influence on such a large diversity of organic farms deployment and the most important included the quality of agricultural production surface. A characteristic feature of organic farms of Lower Silesia is that about 80% of the main type of organic production are meadows and pastures (package 58A) and fodder crops for animal feed (pack 50A to 57A). Cereal Organic-grown consisted of wheat and spelled (from 3% to 30% of producers) quite a lot consisted of more than 20% rye, oats, from 7.5% to 28.6% and buckwheat. Production of vegetables and fruits is listed only in a few percent of the farms. Due to the possibility of high subsidies for orchards planted with walnut, this package (A 67) has become the direction of production of several agricultural producers. Organic farms of Lower Silesia are mainly focused on plant production. Only in about 20% of organic farms production is carried out by organic livestock, which provides cow's milk, goat cheese, veal, beef and eggs. In tourist areas the equines were bred in many organic farms for recreational purposes.

36. Companion cropping chicory with winter forage cereals for grazing and forage conservation. Dry matter yields, nutritive characteristics and mineral content.

• Authors:
  • Ward, G.
  • Jacobs, J.
• Source: Animal Production Science
• Volume: 51
• Issue: 12
• Year: 2011
• Summary: Limitations to the current perennial ryegrass-based pasture system on dryland dairy farms in southern Australia has led to research into alternatives that can produce either additional DM, out of season feed or can improve nutritive characteristics. The use of winter annual crops followed by a summer crop have the potential to achieve these goals but often result in considerable periods where new crops are establishing and feed is not available for consumption. Companion cropping offers an option to overcome these limitations. The experiment reported in this paper examines the DM yields, nutritive characteristics and mineral content of companion cropping wheat or triticale at different sowing rates into an existing chicory monoculture over a 2-year period. We hypothesised that oversowing cereal crops in autumn into an existing stand of chicory would result in improvements in nutritive characteristics at ensiling, without adversely affecting DM yield or subsequent chicory DM yields following harvesting, thus negating the need to sow a new summer forage crop each year. Total DM yields for the chicory and cereal monocultures were similar over the experimental period, while DM yields for all triticale mixtures were higher than the chicory only treatment. Chicory produced lower DM yields for silage but higher DM yields at most grazing events. The crude protein and estimated metabolisable energy content of the chicory only treatment was higher than the cereal monocultures and all triticale/chicory mixtures at both silage harvests with wheat/chicory mixes being intermediate. The proportion of chicory in the mixed swards declined over the course of the experiment. The use of chicory with cereals resulted in no adverse effects on total DM yields, some improvements in nutritive characteristics and mineral content and a more continuous supply of DM compared with double cropping with annual species in winter and summer. This experiment has highlighted the potential of oversowing cereal forages into an existing chicory sward to contribute to DM production on dairy farms in southern Australia. Such forage mixes can provide flexibility into forage systems through the provision of forage for grazing in early winter, the production of high DM yield silage harvests and then subsequent feed supply over summer and early autumn.

37. Allelopathic Cover Crop Prior to Seeding Is More Important Than Subsequent Grazing/Mowing in Grassland Establishment

• Authors:
  • Ball, L. O.
  • Vandever, M. W.
  • Milchunas, D. G.
  • Hyberg, S.
• Source: Rangeland Ecology & Management
• Volume: 64
• Issue: 3
• Year: 2011
• Summary: The effects of grazing, mowing, and type of cover crop were evaluated in a previous winter wheat fallow cropland seeded to grassland under the Conservation Reserve Program in eastern Colorado. Prior to seeding, the fallow strips were planted to forage sorghum or wheat in alternating strips (cover crops), with no grazing, moderate to heavy grazing, and mowing (grazing treatments) superimposed 4 yr after planting and studied for 3 yr. Plots previously in wheat had more annual and exotic species than sorghum plots. Concomitantly, there were much greater abundances of perennial native grass and all native species in sorghum than wheat cropped areas. The competitive advantage gained by seeded species in sorghum plots resulted in large increases in rhizomatous western wheatgrass. Sorghum is known to be allelopathic and is used in crop agriculture rotations to suppress weeds and increase crop yields, consistent with the responses of weed and desired native species in this study. Grazing treatment had relatively minor effects on basal and canopy cover composition of annual or exotic species versus perennial native grass or native species. Although grazing treatment never was a significant main effect, it occasionally modified cover crop or year effects. Opportunistic grazing reduced exotic cheatgrass by year 3 but also decreased the native palatable western wheatgrass. Mowing was a less effective weed control practice than grazing. Vegetative basal cover and aboveground primary production varied primarily with year. Common management practices for revegetation/restoration currently use herbicides and mowing as weed control practices and restrict grazing in all stages of development. Results suggest that allelopathic cover crop selection and opportunistic grazing can be effective alternative grass establishment and weed control practices. Susceptibility, resistance, and interactions of weed and seeded species to allelopathic cover species/cultivars may be a fruitful area of research.

38. Physiological responses and performance of sheep on pasture supplemented with different protein sources.; Respostas fisiologicas e desempenho produtivo de ovinos em pasto suplementados com diferentes fontes proteicas.

• Authors:
  • Pereira, L. G. R.
  • de Oliveira, P. T. L.
  • Voltolini, T. V.
  • Turco, S. H. N.
  • de Araújo, G. G. L.
  • Mistura, C.
  • Menezes, D. R.
• Source: Revista Ceres
• Volume: 58
• Issue: 2
• Year: 2011
• Summary: This study was carried out to evaluate the influence of climatic factors on performance and physiological responses of sheep fed on different protein supplements in grazing Tifton 85 ( Cynodon spp.) irrigated in conditions of Brazilian semiarid climate. A total of 28 male Santa Ines * SPRD (undefined breed), castrated lambs, with initial weight of 28 kg, received three different sources of protein in the supplement (soybean meal, cotton cake and urea) and a control treatment, only on grass. The parameters evaluated were: dry matter intake, average daily gain, physiological parameters [respiratory rate (FR), surface temperature (TS) and rectal temperature (TR)] and environmental parameters. Under the climatic conditions imposed by the experiment, the period of the afternoon led the animals to a condition of high heat stress, regardless of the diet. Supplementation affected roughage intake without changing sheep performance, making it economically unfeasible. Protein source derived from cotton cake and used in the supplement for the lambs in grazing increased FR, influencing their thermal comfort.

39. Sediment-bound and dissolved carbon concentration and transport from a small pastured watershed

• Authors:
  • Shipitalo, M. J.
  • Owens, L. B.
• Source: Agriculture, Ecosystems & Environment
• Volume: 141
• Issue: 1-2
• Year: 2011
• Summary: With the current emphasis on the role of carbon in the environment, agricultural systems and their impacts on the carbon cycle are important parts of the overall issue. Organic carbon lost to streams and rivers can promote bacterial production and microbial respiration of CO(2) to the atmosphere. Although pastures and grasslands are major land uses in the humid U.S., row crop agriculture has received most of the carbon research focus. The objective of this study at the North Appalachian Experimental Watershed near Coshocton, Ohio, was to assess organic carbon transported from a pasture system, particularly on a runoff event basis. A beef cow-calf herd rotationally grazed a paddock during the growing season and was fed hay in this paddock during the dormant season (November-April). Surface runoff and sediment loss was measured and sampled throughout the year from the small watershed in the paddock. Most of the sediment samples were collected during the dormant season. With continuous winter occupancy, the percent vegetative cover was often = 10 kg ha(-1) from the watershed in the winter feeding area. The largest 6 events carried nearly 50% of the total sediment and sediment-attached C lost during this period. Annual losses of sediment and sediment-C varied considerably but averaged 2642 and 140 kg ha(-1), respectively. There was no significant correlation between the amount of sediment transported during individual events and the C concentration on the associated sediment. The pasture sediments have a C enrichment ratio of 1.2-1.5 compared with the 0-2.5 cm soil layer. Pasture sediment-C concentrations were >2x the C concentrations on sediments from nearby row crop watersheds. Published by Elsevier B.V.

40. Stream bed substrate composition adjacent to different riparian land-uses in Iowa, USA

• Authors:
  • Schultz, R. C.
  • Zaimes, G. N.
• Source: Ecological Engineering
• Volume: 37
• Issue: 11
• Year: 2011
• Summary: Extensive land-use changes in Iowa have increased erosional processes and the amount of fines deposited on stream beds. Large amounts of fines cover the other bed substrate that are essential habitat for invertebrates and fish. In Iowa and other agricultural Midwestern states, riparian conservation land-uses are being established to minimize sediment inputs to streams. This study compared stream bed substrate composition in reaches adjacent to: riparian forest buffers, grass filters, row-cropped fields, pastures with cattle fenced out of the stream and continuous, rotational and intensively grazed rotational pastures, in three regions of Iowa. The objective was to examine the impacts of the adjacent riparian land-uses on stream bed substrate composition. The percentages of fines in this study ranged from: 36 to 63% in the central region; 10 to 31% in the northeast region; and 22 to 85% in the southeast region. The high percentage of fines in most stream bed reaches indicates high embeddedness. The high embeddedness resulted in the few significant differences in substrate percentages among riparian land-uses. Decades of agricultural land-uses have heavily impacted stream beds and only significant reductions in surface and bank erosion at the watershed scale can begin to reverse this trend. There were indications that riparian forest buffers and to a lesser degree, pastures with cattle fenced out of the stream, could decrease fines resulting in a more diverse substrate composition. Overall, more targeted approaches for the establishment of conservation land-uses in combination with other restoration practices (e.g. in-stream enhancements) are required to successfully decrease fines on stream beds. (C) 2011 Elsevier B.V. All rights reserved.