• 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:
    • 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:
    • Zarzynska, K.
  • Source: BIULETYN INSTYTUTU HODOWLI I AKLIMATYZACJI ROŚLIN
  • Issue: 259
  • Year: 2011
  • Summary: The investigation, carried out in the years 2008-2009, aimed an assessment of effects of four factors: place of growing, irrigation, presprouting of seed potatoes and use of effective microorganisms on marketable quality of potatoes grown under organic farming system. Eight cultivars, representing different earliness groups, were tested. Genotype had the largest influence on occurrence of external and internal tuber disorders. The place of growing (soil type) affected occurrence of common scab, black scurf, deformations and rust spot. Drip irrigation reduced incidence of common scab, tuber deformations and rust spot. Presprouting of seed potatoes and effective microorganisms exerted the smallest influence on the marketable tuber quality.
  • 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.
  • Authors:
    • Wilson, D.
    • Mischler, R.
    • Duiker, S. W.
    • Curran, W. S.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 1
  • Year: 2010
  • Summary: Rolling-crimping to control hairy vetch ( Vicia villosa Roth) may make organic no-till corn ( Zea mays L.) possible. This study investigated how rolling-crimping date and growth stage of the cover crop affected hairy vetch control and if a rolled-crimped hairy vetch cover crop could supply weed control for no-till corn. Hairy vetch was planted in late August and was rolled and crimped and planted to corn at four dates ("planting dates") between late May and late June at three Pennsylvania locations. Hairy vetch biomass, measured at each planting date, varied from 2000 to 8000 kg ha -1. Hairy vetch control with the roller-crimper varied through the flowering stage and was consistent after early pod set. The hairy vetch cover crop reduced weed density by at least 50%, with annual weeds being affected more than perennials. Total weed biomass was reduced 31, 93, and 94% in different site-years compared with no-cover plots. As corn planting dates were delayed, greater amounts of vetch mulch and lower weed density helped reduce weed biomass. Corn yields in the organic no-till system with a hairy vetch cover crop ranged from 1.1 Mg ha -1 to 9.6 Mg ha -1. Low yields were attributed to incomplete control of hairy vetch, weed competition, reduced corn plant populations, increased insect pests, and possibly inadequate N supply. This study shows that it is possible to kill hairy vetch with a roller-crimper and provide weed control for organic corn, resulting in reasonable corn yields, but that production risk increases.
  • Authors:
    • Maul, J. E.
    • Buyer, J. S.
    • Austin, E. E.
    • Treonis, A. M.
    • Spicer, L.
    • Zasada, I. A.
  • Source: Applied Soil Ecology
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Soil microorganisms (bacteria, fungi) and microfauna (nematodes, protozoa) have been shown to be sensitive to organic amendments, but few experiments have investigated the responses of all these organisms simultaneously and across the soil profile. We investigated the impact of organic amendment and tillage on the soil food web at two depths in a field experiment. Over three growing seasons, field plots received seasonal organic amendment that was either incorporated into the soil (tilled) or not (no-till) as part of a tomato/soybean/corn cropping system. Un-amended, control plots that were either tilled or no-till were also included. We hypothesized that the addition of amendments would have a bottom-up effect on the soil food web, positively influencing the abundance of microorganisms, protozoa, and nematodes, primarily in the surface layers of the soil, but that this effect could be extended into deeper layers via tillage. Organic amendment had positive effects on most measured variables, including organic matter, respiration, protozoan and nematode density, and the abundance of PLFA biomarkers for bacteria and fungi. These effects were more pronounced in the 0-5 cm depth, but most variables increased with amendment in the deeper layer as well, especially with tillage. Denaturing Gradient Gel Electrophoresis (DGGE) of bacterial rDNA fragments indicated that distinct bacterial communities were selected for among tillage and amendment treatments and depths. Nematode faunal indices were not influenced by amendment, however. Increased nematode density in amended soils encompassed all trophic groups of free-living nematodes, with the greatest response among fungal-feeders, particularly with tillage. Increased biomass of microorganisms and decomposer microfauna in amended, tilled soils (0-5 cm depth) corresponded with a decline in the abundance of plant-parasitic nematodes. In control soils (0-5 cm depth), tillage reduced the relative abundance of fungal-feeding nematodes and increased the density of bacterial-feeding nematodes, in particular nematode species contributing to the Enrichment Index. When combined with organic amendment however, tillage was associated with increases in fungal-feeding nematodes and fungal biomarker PLFA. The results of this study suggest that when combined with amendment, tillage enhances the soil food web beyond the effect of amendment alone and is associated with declines in plant-parasitic nematodes.
  • Authors:
    • Ponizil, A.
    • Henriksen, B.
    • Pozdisek, J.
    • Hunady, I.
    • Loes, A. K.
  • Source: Vyzkum v Chovu Skotu
  • Volume: 52
  • Issue: 3
  • Year: 2010
  • Summary: Controlled field trials with legume-cereal mixtures and monocultures were conducted on five organic farms in CR, to determine the suitability for feeding ruminants. Mixtures of 60% peas to 40% cereals (wheat and barley) were compared with peas, wheat, and barley monocultures. The obtained results are useful to assess how mixtures may be included in animal feed rations. For feeding beef cattle, it is most beneficial to harvest green matter in the BBCH 79 growth phase (green ripeness), which is characterized by a higher protein and energy content and a lower fiber content. Advantageous crop for beef cattle appeared to be the mixture with peas and barley, because the crude protein and NEL contents come the closest to the requirements for a balanced state between breakdown and synthesis in the rumen (CP 130 g kg -1, NEL 5.9 MJ kg -1 DM). The results support that legume-cereal intercropping is a feasible technology to produce high quality feed on organic farms, which may provide animals with good health, and potential to utilize their genetic capacity for growth and production.
  • Authors:
    • Guiducci, M.
    • Tosti, G.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Intercropping cereals and grain legumes is a common practice because of the advantages in N use, in pest and volunteer plant smothering, but when the grains need to be separated, there are several technical difficulties. These problems may be overcome by adopting a particular form of intercropping (termed "temporary intercropping") where the coexistence of the crops is limited to a portion of their life cycles. In a cereal-legume temporary row-intercropping, the legume component is ploughed into the soil before cereal shooting; thus the legume is used with a mere fertility purpose in order to improve N availability for the cereal component. The presence of such a positive effect, already confirmed in permanent intercropping, needs to be verified in temporary intercropping systems. In an organic farming system, a field experiment was carried out in two consecutive years (2005 and 2006) to evaluate the technical feasibility of a temporary intercropping between three varieties of durum wheat ( Triticum durum Desf.) and faba bean ( Vicia faba L. var. minor Beck.) and to test the effects on interspecific competition for light, N availability, cereal grain yield and quality. The species were temporarily intercropped following an additive design, and there was no fertilisation or crop protection. The N incorporated into the soil by the faba bean biomass was rather stable across years. The competitive effect of the legume reduced the biomass accumulation of the intercropped wheat, but the cereal N status was considerably improved. After the faba bean incorporation into the soil, the marked asymmetry of the temporary intercropped wheat (i.e. large inter-row space coupled with high plant density in the row) affected the radiation balance, nevertheless the yield was positively affected and the wheat grain protein content was increased to an excellent (from 12.0 to 13.9% in 2005) or a good (from 10.2 to 11.5% in 2006) level. Temporary intercropping was shown to be excellent method to improve the quality of organic durum wheat in the Mediterranean environmental conditions.
  • Authors:
    • Trawczynski, C.
  • Source: Journal of Research and Applications in Agricultural Engineering
  • Volume: 55
  • Issue: 4
  • Year: 2010
  • Summary: The aim of this investigation was to determine balance of nitrogen, phosphorus and potassium in organic crop rotation system on light soil. The crop rotation comprised following agricultural plant species: potato, oat, yellow lupine, rye, phacelia. Apart from these main species 3 plants were cultivated as intercrop: field pea, white mustard, serradella. Before potato cultivation the manure in dose of 25 t.ha -1 was applied. The calculations were based on real data of obtained yields and nutrients content in the yields. The "on surface of field" method was used in this investigation. In the crop rotation positive balance of nitrogen (+20,4 kg N.ha -1 per year -1) and slightly negative one for phosphorus (-3,1 kg P.ha -1 per year -1) and potassium (-4,5 kg K.ha -1 per year -1) were noted.