• Authors:
    • Gertsson, U.
    • Linden, B.
    • Gunnarsson, A.
  • Source: HortScience
  • Volume: 46
  • Issue: 5
  • Year: 2011
  • Summary: Nitrogen (N) tied up in or lost from decomposing biomass decreases the residual N effects of green manure and of other crop residues. During anaerobic degradation in a biogas digestor (biodigestion), N mineralization takes place under conditions in which losses can be kept to a minimum. Therefore, biodigestion of green manure biomass and beet foliage was tested to generate readily available N and compared with a direct green manure fertilization system. The effluent was applied as fertilizer in field experiments on a sandy soil as a tool for improving N supply for an organic farming system. Data from the field experiments were used for simulating the amount of net inorganic N equivalents (inorganic N equivalents from effluent plus inorganic N equivalents from pre-crops) in three crop sequences: A) green manure ley, red beets rye; B) harvested ley, red beets, winter rye; and C) harvested ley, spring barley, red beets in which (B) and (C) represented biogas nutrient management systems and (A) a green manure system. When all available effluent from biogas production from 1 ha of grass clover ley with two or three harvests (2H-ley or 3H-ley) and one hectare of beet foliage was used as a fertilizer for red beets (Beta vulgaris var. conditiva Alef) after barley (Hordetum vulgare L.), the yield of marketable red beets increased by 5.7 Mg.ha(-1) (33%) with effluent from 2H-ley and beet foliage and 9.1 Mg.ha(-1) (53%) with effluent from 3H-ley and beet foliage compared with red beets grown without effluent fertilization after a green manure ley. When total dry matter production was taken into account, the advantage for the BC systems with 2H- and 3H-Iey was 15% and 28%, respectively. The nitrate concentration in the red beets was not higher with effluent supplied at this level than with green manure as the only N source. The simulated amount of net inorganic N equivalents was 128 kg N for the whole of crop sequence (C) with 1 ha of each crop and where effluent supply to red beets was based on digested biomass in ley and beet tops. The corresponding amount of net inorganic N equivalents for the green manure crop sequence (A), in which no effluent was supplied, was 73 kg N. Unused soil mineral N (0- to 90-cm depth) at red beet harvest indicated that the risk of leaching in BG systems was lower than in GrM systems (88, 76, and 61 kg N(min)/ha left after unmanured beets after Gr-M-Iey, low manured beets after 3H-ley and high manured beets after barley, respectively). Effluent fertilization of red beets directly after 2H- and 3H-ley gave unexpectedly low yield responses compared with red beets after barley. The reasons may be the result of nutritional imbalance of other nutrients than N or may be plant pathological in nature. The conclusion is that a nutrient management system with biodigestion can increase net inorganic N equivalents and reduce risk for N leaching, but inappropriate use of the effluent, i.e., at an unsuitable point in the crop rotation, may negate the benefits.
  • Authors:
    • Jalli, M.
    • Huusela-Veistola, E.
    • Hannukkala, A. O.
    • Hakala, K.
    • Peltonen-Sainio, P.
  • Source: Agricultural and Food Science
  • Volume: 20
  • Issue: 1
  • Year: 2011
  • Summary: A longer growing season and higher accumulated effective temperature sum (ETS) will improve crop production potential in Finland. The production potential of new or at present underutilised crops (e. g. maize (Zea mays L.), oilseed rape (Brassica napus L.), lucerne (Medicago sativa L.)) will improve and it will be possible to grow more productive varieties of the currently grown crops (spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), oats (Avena sativa L.)). Also cultivation of autumn sown crops could increase if winters become milder and shorter, promoting overwintering success. Climatic conditions may on the other hand become restrictive in many ways. For example, early season droughts could intensify because of higher temperatures and consequent higher evaporation rates. Current low winter temperatures and short growing season help restrict the development and spread of pests and pathogens, but this could change in the future. Longer growing seasons, warmer autumns and milder winters may initiate new problems with higher occurrences of weeds, pests and pathogens, including new types of viruses and virus vectors. Anoxia of overwintering crops caused by ice encasement, and physical damage caused by freezing and melting of water over the fields may also increase. In this study we identify the most likely changes in crop species and varieties in Finland and the pest and pathogen species that are most likely to create production problems as a result of climate change during this century.
  • Authors:
    • Shostak, Z. A.
  • Source: Russian Meteorology and Hydrology
  • Volume: 36
  • Issue: 12
  • Year: 2011
  • Summary: The methods are presented of agrometeorological forecasting of winter and spring grain crops for the district, all types of farm units, and field taking account of the regional crop forecast, weather conditions, cereal cropping technologies, and soil cultivation level. The additional yields of winter and spring wheat and spring barley and oat are developed depending on the soil cultivation level, summertime soil moistening, and doses of mineral fertilizers. The method tested on the basis of independent data demonstrated that the accuracy of such forecasts is 83-99% for the fields with intensive cultivation technology and 80% for the farm units.
  • Authors:
    • Wierzbicka, A.
  • Source: Journal of Research and Applications in Agricultural Engineering
  • Volume: 56
  • Issue: 4
  • Year: 2011
  • Summary: The aim of the study was to assess the dry matter, starch, vitamin C, glycoalkaloids and nitrates content in potato tubers from organic system cultivated in light, sandy soil of IHAR Jadwisin (Mazovia). The objective of this work was to evaluate the tuber chemical composition of 8 cultivars of potatoes under the influence of the irrigation. Irrigation had no effect on dry matter, starch and vitamin C, but significantly affected glycoalkaloids and nitrates. The study showed a significant effect of variety and years of research on the content of dry matter, starch, vitamin C, nitrates and glicoalkaloids. Genotypic differences were the most evident in the case of nitrates and glycoalkaloids content. Under the influence of irrigation decreased the nitrate content and increased content of glycoalkaloids.
  • Authors:
    • Schoenau, G.
    • Tabil, L.
    • Adapa, P.
  • Source: Biomass and Bioenergy
  • Volume: 35
  • Issue: 1
  • Year: 2011
  • Summary: Grinding experiments were conducted on non-treated and steam exploded barley, canola, oat and wheat straw using a forage chopper and a hammer mill (screen sizes of 30, 6.4, 3.2 and 1.6 mm) to determine specific energy requirements, and geometric mean particle size and distribution of ground material. The bulk density of non-treated biomass was significantly higher than bulk density of steam exploded agricultural biomass. For non-treated agricultural straw, the particle density of canola and oat straw significantly increased with a decrease in hammer mill screen size from 30 to 1.6 mm. The particle density of steam exploded barley and oat straw was significantly higher than non-treated straw, except for barley at 6.4 mm hammer mill screen size. The particle density of steam exploded canola straw was not statistically different from non-treated straw. The chopper consumed highest (3.15 +/- 0.09 kWh t(-1)) and lowest (1.96 +/- 0.33 kWh t(-1)) specific energy to chop barley and canola straw, respectively. The highest and lowest specific energy was consumed by wheat (42.57 +/- 2.04 kWh t(-1)) at 1.6 mm and canola (1.46 +/- 0.30 kWh t(-1)) straws ground using 30 mm hammer mill screen size, respectively. For steam exploded agricultural biomass, the highest and lowest specific energy was consumed by oat (33.18 +/- 3.10 kWh t(-1)) at 1.6 mm and canola (2.69 +/- 0.26 kWh t(-1)) straws ground using 6.4 mm hammer mill screen size, respectively. Specific energy required by hammer mill to grind non-treated and steam exploded barley, canola, oat and wheat straw showed a negative power correlation with hammer mill screen sizes. (C) 2010 Elsevier Ltd. All rights reserved.
  • Authors:
    • Bandici, G. E.
    • Ardelean, I.
  • Source: Analele Universităţii din Oradea, Fascicula ProtecÅ£ia Mediului
  • Volume: 17
  • Year: 2011
  • Summary: The paper based on the research carried out during 2008-2010 in the long term trial placed in 1990 on the preluvosoil from Oradea. Three kind of crop rotation (wheat - monocrop; wheat - maize; wheat - maize - soybean) were studied in unirrigated and irrigated conditions. The smallest content of the protein from wheat grains were registered in the wheat monocrop both nonirrigated and irrigated variant. In the wheat-maize and wheat-maize-soybean crop rotation the values registered were significant statistically bigger than in wheat monocrop. Irrigation determined the decrease of the protein content.
  • Authors:
    • Brown, M. G.
    • Merwin, I. A.
    • Atucha, A.
  • Source: HortScience
  • Volume: 46
  • Issue: 8
  • Year: 2011
  • Summary: Groundcover management systems (GMSs) are essential for fruit production, but very few long-term studies have evaluated orchard GMS sustainability. We evaluated four GMSs-pre-emergence soil-active herbicides (PreHerb), post-emergence herbicide (PostHerb), a turfgrass cover crop (Sod), and hardwood bark mulch (Mulch)-in an apple (Malus domestica Borkh.) orchard over 16 years of continuous observation. There were no consistent long-term trends in fruit yields among GMSs, although during the first 5 years, yields were lower in trees on Sod. Tree growth was greater in PostHerb and Mulch than in Sod during the first 5 years, and during the next decade, trees in Mulch plots were consistently larger than in other GMSs. Total soil nitrogen (N) and carbon (C) content, C-to-N ratios, and essential plant nutrients were much greater in the Mulch soil after 16 years of treatments. Long-term responses of trees to groundcover vegetation indicated that apple trees respond adaptively to compensate for weed and grass competition. Year-round elimination of surface vegetation with residual soil active herbicides may be unnecessary or even detrimental for orchard productivity and soil fertility in established orchards. Post-emergence herbicides that reduce weed competition primarily during the summer months may offer an optimal combination of weed suppression and soil conservation.
  • Authors:
    • Elfstrand, S.
    • Båth, B.
    • Wetterlind, J.
    • Stenberg, M.
    • Bergkvist, G.
  • Source: Field Crops Research
  • Volume: 120
  • Issue: 2
  • Year: 2011
  • Summary: Four two-year field trials, arranged in randomised split-plots, were carried out in southern Sweden with the aim of determining whether reduced N fertiliser dose in winter wheat production with spring under-sown clover cover crops, with or without perennial ryegrass in the seed mixture, would increase the clover biomass and hence the benefits of the cover crops in terms of the effect on the wheat crop, on a subsequent barley crop and on the risk of N leaching. Four doses of nitrogen (0, 60, 120 or 180 kg N ha(-1)) constituted the main plots and six cover crop treatments the sub-plots. The cover crop treatments were red clover (Trifolium pratense L). white clover (Trifolium repens L) and perennial ryegrass (Lolium perenne L.) in pure stands and in mixtures. The winter wheat (Triticum aestivum L.) was harvested in August and the cover crops were ploughed under in November. The risk of N leaching was assessed in November by measuring the content of mineral N in the soil profile (0-30, 30-90 cm). In the following year, the residual effects of the cover crops were investigated in spring barley (Hordeum distichon L) without additional N. Under-sowing of cover crops did not influence wheat yield, while reduced N fertiliser dose decreased yield and increased the clover content of the cover crops. When N was applied, the mixed cover crops were as effective in depleting soil mineral nitrogen as a pure ryegrass cover crop, while pure clover was less efficient. The clover content at wheat harvest as well as the amount of N incorporated with the cover crops had a positive correlation with barley yield. Spring barley in the unfertilised treatments yielded, on average, 1.9-2.4 Mg DM ha(-1) more in treatments with clover cover crops than in the treatment without cover crops. However, this positive effect decreased as the N dose to the preceding wheat crop increased, particularly when the clover was mixed with grass. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Hedtcke, J. L.
    • Stoltenberg, D. E.
    • Posner, J. L.
    • Bernstein, E. R.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 4
  • Year: 2011
  • Summary: A major challenge that organic grain crop growers face is weed management. The use of a rye (Secale cereale L.) cover crop to facilitate no-tillage (NT) organic soybean [Glycine max (L.) Merr.] production may improve weed suppression and increase profitability. We conducted research in 2008 and 2009 to determine the effect of rye management (tilling, crimping, and mowing), soybean planting date (mid-May or early June), and soybean row width (76 or 19 cm), on soybean establishment, soil moisture, weed suppression, soybean yield, and profitability. Soybean establishment did not differ between tilled and NT treatments; and soil moisture measurements showed minimal risk of a drier soil profile in NT rye treatments. Rye mulch treatments effectively suppressed weeds, with 75% less weed biomass than in the tilled treatment by mid-July. However, by this time, NT soybean competed with rye regrowth, were deficient in Cu, and accumulated 22% as much dry matter (DM) and 28% as much N compared to the tilled treatment. Soybean row width and planting date within NT treatments impacted soybean productivity but not profitability, with few differences between mowed and crimped rye. Soybean yield was 24% less in the NT treatments than the tilled treatment, and profitability per hectare was 27% less. However, with fewer labor inputs, profitability per hour in NT rye treatments was 25% greater than in tilled soybean; in addition, predicted soil erosion was nearly 90% less. Although soybean yields were less in NT rye mulch systems, they represent economically viable alternatives for organic producers in the Upper Midwest.
  • Authors:
    • Chiriac, I. P.
    • Bălan, A.
    • Lipșa, F. D.
    • Ulea, E.
  • Source: Lucrări ŞtiinÅ£ifice
  • Volume: 53
  • Issue: 1
  • Year: 2010
  • Summary: Research was carried out on rapeseed ( Brassica napus L.) field trials located in the south region of Moldavian plain (Ezareni Farm), studying the effects of fertilization (organic, mineral) and soil tillage systems on soil population. Soil tillage has been realized with plough (in classic system), with chisel, rotary harrow (in minimum soil tillage) and in no-till system. The objectives of this investigation were to isolate and quantify the existing microbial population in soil (Gram positive bacteria, Gram negative bacteria, micromycetes) establishing their participation ratio, the main fungus genres which activate in soil and their activity level for each variant. The results illustrate the influence of the fertilization and soil tillage systems on the dinamic of microorganisms population, on the relationship between the main groups (bacteria and fungi), and on the micromycetes spectrum determined in each variant of our experiment.