• Authors:
    • Breland, T. A.
    • Bleken, M. A.
    • Bakken, L. R.
    • Lunde, H. W.
    • Borgen, S. K.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: We applied a mechanistic ecosystem model to investigate the production and environmental performances of (1) current agricultural practice on two fields of a stockless organic cereal farm in southeast Norway and (2) alternative cereal-ley rotations and plowing time scenarios. Scenarios were simulated using historic weather data and a climate change scenario. Measured and simulated soil mineral N concentrations were generally low (1-4 g N m(-2)) and in good agreement. Simulated nitrate leaching was similar for the two fields, except when an extended period of black fallow weeding was practiced on one of them. Scenario simulations indicated that continuous cereal cropping undersown with a clover-grass winter cover crop performed best when evaluated by whole-rotation grain yield, the N yield/input-, and N loss/yield-ratios, and greenhouse gas emissions. However, the rotation had the largest soil organic matter losses. The N use and loss efficiency indicators were especially poor when ley years occurred consecutively and under fall plowing. Total greenhouse gas emissions were, however, smaller for the fall-plowed scenarios. In conclusion, our results indicated a modest potential for improving stockless systems by management changes in plowing time or crop rotation, which was hardly different in the climate change scenarios, although nitrate leaching increased substantially in the winter. Alternative strategies seem necessary to substantially improve the N-use efficiency in stockless organic grain production systems, e.g., biogas production from green manure and subsequent recycling of the digestate. Abandoning the stockless system and reintegrating livestock should also be considered.
  • Authors:
    • Klonsky, K. M.
    • Demoura, R.
    • Elkins, R. B.
    • Ingels, C. A.
    • Lanini, W. T.
    • Shackel, K. A.
  • Source: Acta Horticulturae
  • Issue: 909
  • Year: 2011
  • Summary: In 2009 and 2010, four weed control treatments (in-row mowing, landscape fabric, wood chips, and organic herbicide) and three fertilizer treatments (chicken manure at high vs. low rate and feather meal) were compared in an organic, no-till 'Bosc' pear ( Pyrus communis) orchard with solid-set sprinklers. Weed control in the landscape fabric and wood chip treatments was excellent, and multiple herbicide applications per year resulted in partial control. There were no significant yield differences among treatments, and little difference in fruit diameter or weight. There were no significant differences in trunk growth between treatments. The wood chip treatment had significantly lower stem water potential than other treatments in August 2009 only. In both years, the N content of leaves in mow+no fertilizer was significantly lower than most high-rate manure treatments, and leaf P content followed the opposite trend. Wood chips and fabric tended to have fewer vole holes than in-row mowing, and the herbicide treatment was intermediate. Assuming that landscape fabric lasts 8 years, it is only slightly more expensive per year than in-row mowing alone. An organic herbicide program is more expensive because of the herbicide cost and the many applications required. Wood chips were by far the most expensive treatment because of the cost of chips and spreading them, as well as the need to reapply every year. The use of a low rate of chicken manure was the cheapest fertilization strategy. Doubling that rate doubled the total costs, whereas the use of feather meal was about three times the cost of low-rate manure application for an equivalent amount of N.
  • Authors:
    • Nenova, L.
    • Ivanova, I.
    • Stoyanova, S.
  • Source: Banat's Journal of Biotechnology
  • Volume: 2
  • Issue: 4
  • Year: 2011
  • Summary: A study was conducted from 2008 to 2010 in Bulgaria to evaluate the weed infestation in field crops, grown in crop rotation by organic farming. Beans cv. Obraztsov chiflik, wheat cv. Yantur, soyabeans cv. Zarya, and winter oats line RS-2 were studied. Two variants were used and foliar fertilization using Humustim in four replications, the size of harvesting plot was 52. 5 m 2. Crop rotation technological schemes were applied according to the requirements of the organic farming without using chemicals. During crop rotation, the density of perennial weeds remained relatively constant. In variants with fertilization by Humustim, the total number of weeds decreased compare to those without fertilization. The lowest density of weed infestation was observed in wintering oats, grown after soybeans-100 pcs. /m 2 and in wheat, grown after field beans-122 pcs. /m 2.
  • Authors:
    • Nord, E. A.
    • Curran, W. S.
    • Mortensen, D. A.
    • Mirsky, S. B.
    • Jones, B. P.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Rolled cover crop mulches can suppress weeds in subsequent cash crops, reduce the need for herbicides, and allow organic no-till cash crop establishment. This study investigated the weed suppressiveness of a cereal rye ( Secale cereale L.) cover crop mulch across varying weed seedbank density. Cereal rye was seeded at two dates in the fall and terminated at five dates in the spring to create biomass ranging from 100 to 1600 g m -2. The first three termination dates included both herbicide (glyphosate) and rolling of the rye, while later three dates were only rolled. Soybean [ Glycine max (L.) Merr.] was no-till planted after rye termination, and weed biomass and soybean yield were assessed. Spring termination date more strongly affected cereal rye biomass than fall planting date; a termination delay of 5 to 15 d compensated for a planting delay of 30 d. Weed biomass generally declined with increasing cereal rye biomass, and this relationship was stronger at higher weed seedbank densities. Supplemental weed control reduced weed biomass compared to no supplemental control and postherbicide was more effective than cultivation. While increasing cereal rye biomass was associated with a decline in soybean yield in 2009, it did not consistently impact soybean stand. Instead soybean stand establishment appeared to be impacted by high cover crop biomass and changing edaphic conditions at planting. Future research should focus on improved technology for direct seeding in high residue environments and developing longer term cropping systems less reliant on tillage and herbicides.
  • Authors:
    • Parr, M.
    • Grossman, J. M.
    • Reberg-Horton, S. C.
    • Brinton, C.
    • Crozier, C.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Sixteen winter annual cover crop cultivars were grown in North Carolina to determine total N accumulation, biological N fixation (BNF) potential, and compatibility with a roller-crimper-terminated organic corn ( Zea mays L.) production system. Cover crops and termination dates were tested in a stripped block design. Treatments included hairy vetch ( Vicia villosa Roth), common vetch ( Vicia sativa L.), crimson clover ( Trifolium incarnatum L.), Austrian winter pea ( Pisum sativum L.), berseem clover ( Trifolium alexandrinum L.), subterranean clover ( Trifolium subterraneum L.), narrow leaf lupin ( Lupinus angustifolius L.), and Balansa clover ( Trifolium michelianum Savi.), as well as bicultures of rye ( Secale cereale L.), hairy vetch, and Austrian winter pea. Roller-crimper termination occurred in mid-April, early May, and mid-May. Total biomass, N concentration, and C/N ratios were determined for cover crops at all roll times and natural 15N abundance at the optimal kill date. Hairy vetch and crimson clover monocultures had the greatest overall biomass in 2009, and bicultures the greatest biomass in 2010. Crimson clover successfully terminated in late April, hairy vetch and Austrian winter pea in mid-May, and berseem clover and common vetch in late May. All cover crops except lupin and subterranean clover derived between 70 and 100% of their N from the atmosphere. Corn response to cover crop mulches was significantly affected by the time of rolling, with poor stands resulting from competition with insufficiently terminated mulches. Crimson, Balansa, and subterranean clover mulches resulted in poor corn yields despite relatively high levels of total N. The highest corn yields were achieved in hairy vetch and rye plus hairy vetch bicultures.
  • Authors:
    • Poje, T.
  • Source: SAD, Revija za Sadjarstvo, Vinogradnistvo in Vinarstvo
  • Volume: 22
  • Issue: 1
  • Year: 2011
  • Summary: Spreading organic fertilizers in perennial plantations, such as vineyards and orchards, by mechanical means is discussed, and the different basic types of manure spreader suited to this operation are described.
  • Authors:
    • Scherer, E. E.
  • Source: Agropecuaria Catarinense
  • Volume: 24
  • Issue: 2
  • Year: 2011
  • Summary: Organic agriculture in no-till system requires a new set of producer skills especially in the area of soil fertility and fertilizer use. In a field experiment in organic system in Chapeco, SC, Southern Brazil, the effect of different organic fertilizers (poultry dry litter, swine deep litter, swine composted manure, cattle composted manure and liquid swine manure) on the corn and common been yields was investigated. The organic fertilizers were scattered on the soil surface in the no-till system on the day of the sowing of common bean and corn. The solid manure was applied at 5 and 10 t/ha, dry weight, and the liquid manure at 30 and 60 m 3/ha for common beans and corn, respectively. A completely randomized block experimental design with six replications was used. The utilization of solid and liquid organic manure increased the grain yield of both cultures in all six years. Common beans and corn grain average yield with organic fertilizers use was 30% and 54% greater than yield without fertilizer, respectively. Solid swine manure and organic compost had a better performance on common bean grain yield, and liquid swine manure on corn yield.
  • Authors:
    • Slepetiene, A.
    • Slepetys, J.
  • Source: Grassland farming and land management systems in mountainous regions. Proceedings of the 16th Symposium of the European Grassland Federation
  • Year: 2011
  • Summary: The main objective of the current study was to evaluate the effects of six legume species ( Trifolium pratense, Medicago sativa, Trifolium repens, Galega orientalis, Medicago lupulina, Trifolium resupinatum) ploughed down as green manure, on the seed yield of timothy ( Phleum pratense) and meadow fescue ( Festuca pratensis). Legumes were undersown into barley. In the first year of production legumes were chopped and ploughed down for green manure in June. The sown timothy and meadow fescue were used for organic seed for three years. Although T. resupinatum grew well in the year of sowing it completely disappeared after winter. Based on 3-year mean production data, the highest timothy and meadow fescue seed yield was obtained after ploughing down a mixture of three legumes ( T. pratense+ M. sativa+ T. repens). Seed yield increased by 27.8-33.1%. Ploughed-down pure legumes (except G. orientalis) gave a lower but significant increase in seed yield. Having ploughed down legumes, the positive effect on organic seed was more substantial in the second and third years of production.
  • Authors:
    • Maul, J. E.
    • Meisinger, J. J.
    • Cavigelli, M. A.
    • Spargo, J. T.
    • Mirsky, S. B.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 90
  • Issue: 2
  • Year: 2011
  • Summary: Sustainable soil fertility management depends on long-term integrated strategies that build and maintain soil organic matter and mineralizable soil N levels. These strategies increase the portion of crop N needs met by soil N and reduce dependence on external N inputs required for crop production. To better understand the impact of management on soil N dynamics, we conducted field and laboratory research on five diverse management systems at a long-term study in Maryland, the USDA- Agricultural Research Service Beltsville Farming Systems Project (FSP). The FSP is comprised of a conventional no-till corn ( Zea mays L.)-soybean ( Glycine max L.)-wheat ( Triticum aestivum L.)/double-crop soybean rotation (NT), a conventional chisel-till corn-soybean-wheat/soybean rotation (CT), a 2 year organic corn-soybean rotation (Org2), a 3 year organic corn-soybean-wheat rotation (Org3), and a 6 year organic corn-soybean-wheat-alfalfa ( Medicago sativa L.) (3 years) rotation (Org6). We found that total potentially mineralizable N in organic systems (average 315 kg N ha -1) was significantly greater than the conventional systems (average 235 kg N ha -1). Particulate organic matter (POM)-C and -N also tended to be greater in organic than conventional cropping systems. Average corn yield and N uptake from unamended (minus N) field microplots were 40 and 48%, respectively, greater in organic than conventional grain cropping systems. Among the three organic systems, all measures of N availability tended to increase with increasing frequency of manure application and crop rotation length (Org2 < Org3 ≤ Org6) while most measures were similar between NT and CT. Our results demonstrate that organic soil fertility management increases soil N availability by increasing labile soil organic matter. Relatively high levels of mineralizable soil N must be considered when developing soil fertility management plans for organic systems.
  • Authors:
    • Kravchenko, A. N.
    • Mokma, D. L.
    • Corbin, A. T.
    • Syswerda, S. P.
    • Robertson, G. P.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 1
  • Year: 2011
  • Summary: Soil C sequestration research has historically focused on the top 0 to 30 cm of the soil profile, ignoring deeper portions that might also respond to management. In this study we sampled soils along a 10-treatment management intensity gradient to a 1-m depth to test the hypothesis that C gains in surface soils are offset by losses lower in the profile. Treatments included four annual cropping systems in a corn ( Zea mays)-soybean ( Glycine max)-wheat ( Triticum aestivum) rotation, perennial alfalfa ( Medicago sativa) and poplar ( Populus * euramericana), and four unmanaged successional systems. The annual grain systems included conventionally tilled, no-tillage, reduced-input, and organic systems. Unmanaged treatments included a 12-yr-old early successional community, two 50-yr-old mid-successional communities, and a mature forest never cleared for agriculture. All treatments were replicated three to six times and all cropping systems were 12 yr post-establishment when sampled. Surface soil C concentrations and total C pools were significantly greater under no-till, organic, early successional, never-tilled mid-successional, and deciduous forest systems than in the conventionally managed cropping system ( p≤0.05, n=3-6 replicate sites). We found no consistent differences in soil C at depth, despite intensive sampling (30-60 deep soil cores per treatment). Carbon concentrations in the B/Bt and Bt2/C horizons were lower and two and three times more variable, respectively, than in surface soils. We found no evidence for C gains in the surface soils of no-till and other treatments to be either offset or magnified by carbon change at depth.