• Authors:
    • Barbercheck, M. E.
    • Jabbour, R.
  • Source: Biological Control
  • Volume: 51
  • Issue: 3
  • Year: 2009
  • Summary: The growing demand for organic products creates opportunities for farmers. Information on the consequences of management practices can help farmers transition to organic and take advantage of these prospects. We examined the interaction between soil disturbance and initial cover crop on naturally occurring entomopathogenic fungi (EPF) during the 3-year transition to organic production in a feed grain rotation in central Pennsylvania. Our experiment included four systems comprised of a factorial combination of two levels of primary tillage (full vs. reduced) and two types of initial cover crop (timothy/clover vs. rye/vetch). The cropping sequence consisted of an initial cover crop, followed by soybean, and finally, maize. The entire experiment was replicated in time, with the initiation lagged by 1 year. We detected four species of EPF (Metarhizium anisopliae, Beauveria bassiana, Isaria fumosorosea, and Isaria farinosa) by bioassay of soil samples collected four times during each field season. The latter three species were detected infrequently; therefore, we focused statistical analysis on M. anisopliae. Detection of M. anisopliae varied across sampling date, year in crop sequence, and experimental start, with no consistent trend across the 3-year transition period. M. anisopliae was isolated more frequently in the systems initiated with timothy/clover cover crops and utilizing full tillage; however, we only observed a tillage effect in one temporal replicate. M. anisopliae detection was negatively associated with soil moisture, organic matter, and zinc, sulfur, and copper concentrations in the soil. This study helps to inform farmers about management effects on soil function, specifically conservation biological control. (C) 2009 Elsevier Inc. All rights reserved.
  • Authors:
    • Pawar, A. D.
    • Bhoge, R. S.
  • Source: Annals of Plant Physiology
  • Volume: 23
  • Issue: 2
  • Year: 2009
  • Summary: The effects of organic and inorganic farming practices on the performance of sorghum were studied in Rahuri, Maharashtra, India, during the rabi season of 2007-08. The treatments consisted of: (T1) farmyard manure (FYM; 10 t/ha); (T2) dhaincha [ Sesbania aculeata] green manure at 10 t/ha; (T3) 75% of the recommended NPK fertilizer rates (RFR) + 3 t FYM/ha + Azospirillum + PSB [phosphate solubilizing bacteria]; (T4) 100% RFR (100:50:50 kg NPK/ha); (T5) farmers' practice (10 kg N + 3 t FYM/ha); and (T6) soyabean-rabi sorghum rotation. T1, T2 and T3 induced early flowering, whereas T4 delayed flowering. T3 resulted in the highest 100-seed weight (35.80 g), grain yield (29.24 quintal/ha), fodder yield (53.14 quintal/ha), and benefit-cost ratio (2.17). The results indicated that the amount of inorganic fertilizers can be reduced by 25% using organic fertilizers as substitutes. [1.0 quintal=100.0 kg].
  • Authors:
    • Feltran, J. C.
    • De Castro, C. M.
    • De Almeida, D. L.
    • Valle, Teresa L.
    • Duarte Ribeiro, R. De L.
    • Pries Devide, A. C.
  • Source: Bragantia
  • Volume: 68
  • Issue: 1
  • Year: 2009
  • Summary: Organic systems were evaluated for cassava root production directed to human comsumption in natura, at Seropedica-RJ. Treatments consisted of: cassava ('IAC 576-70') in single cropping and its intercropping with corn ('Eldorado'), cowpea ('Maua') or corn plus cowpea. The organic management was standardized and the experimental area was submitted to artificial irrigation during the period of stay of maize in the system. "Green" (immature) corn ears were harvested at the "point" required for fresh marketing and the shoot placed on the ground. The cowpea was included to function as green manure being Cut at flowering with residues left on the soil Surface. Corn and cowpea were sown between cassava rows, in an alternate design, following the first weeding of the main crop (cassava). The cultivar IAC 576-70 showed suitability with respect to organic management, yielding approximatelu 31 Mg ha(-1) of marketable roots. No significant differences were detected between cassava single cropping and any of the intercropping tested systems. Thus, corn crop has considerable potential for additional income to the growers. Yield of 'Eldorado' corn averaged 18.125 ears ha(-1) correspponding to 5,1 Mg ha-1. Residues coming from cowpea cutting brought about an input close to 12 Mg ha(-1), which meant an expressive contribution in nutrient elements, especially nitrogen (about 44 kg N ha(-1)). The legume crop, in addition, completely covered cassava inter-rows demonstrating its potential for controlling erosion and weeds. The triple intercropping becomes advantageous considering that corn harvesting would justify irrigation and that inclusion of cowpea meant benefitial effects to the system and did not interfere on cassava yield.
  • Authors:
    • Klimek, S.
    • Steinmann, H-H
    • Ulber, L.
    • Isselstein, J.
  • Source: Weed Research
  • Volume: 49
  • Issue: 5
  • Year: 2009
  • Summary: Weed species diversity may benefit from organic farming due to enhanced temporal diversification of crop species in a rotation and omission of herbicide applications. However, in intensively managed conventional systems, little evidence exists as to what extent diversified crop rotations contribute to higher weed species richness. Using an on-farm approach, the effect of crop rotation (organic, conventional diverse (CD) and conventional simple (CS) crop rotations) and weed control (with vs. without) on weed species richness, cover, community composition and crop biomass, was analysed in 24 winter wheat fields. Weed species with beneficial functions for invertebrates and birds were analysed separately. Weed species richness was higher in the organic crop rotation, but did not differ between CD and CS crop rotations. Weed control treatment reduced species richness in both conventional rotations, but not in the organic one. Redundancy analyses revealed that crop rotation intensity accounted for the largest part of the explained variation in weed species composition. Results from the study indicate that the maintenance of weed species richness and conservation of species with important ecological functions requires not only temporal diversification of crop species in the rotation, but also an adjustment of weed control strategies.
  • Authors:
    • Teasdale, J. R.
    • Hanson, J. C.
    • Hima, B. L.
    • Cavigelli, M. A.
    • Conklin, A. E.
    • Lu, Y. C.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 24
  • Issue: 2
  • Year: 2009
  • Summary: We present the results from enterprise budget analyses for individual crops and for complete rotations with and without organic price premiums for five cropping systems at the US Department of Agriculture-Agricultural Research Service (USDA-ARS) Beltsville Farming Systems Project (FSP) from 2000 to 2005. The FSP is a long-term cropping systems trial established in 1996 to evaluate the sustainability of organic and conventional grain crop production. The five FSP cropping systems include a conventional, three-year no-till corn ( Zea mays L.)-rye ( Secale cereale L.) cover crop/soybean ( Glycine max (L.) Merr)-wheat ( Triticum aestivum L.)/soybean rotation (no-till (NT)), a conventional, three-year chisel-till corn-rye/soybean-wheat/soybean rotation (chisel tillage (CT)), a two-year organic hairy vetch ( Vicia villosa Roth)/corn-rye/soybean rotation (Org2), a three-year organic vetch/corn-rye/soybean-wheat rotation (Org3) and a four- to six-year organic corn-rye/soybean-wheat-red clover ( Trifolium pratense L.)/orchard grass ( Dactylis glomerata L.) or alfalfa ( Medicago sativa L.) rotation (Org4+). Economic returns were calculated for rotations present from 2000 to 2005, which included some slight changes in crop rotation sequences due to weather conditions and management changes; additional analyses were conducted for 2000 to 2002 when all crops described above were present in all organic rotations. Production costs were, in general, greatest for CT, while those for the organic systems were lower than or similar to those for NT for all crops. Present value of net returns for individual crops and for full rotations were greater and risks were lower for NT than for CT. When price premiums for organic crops were included in the analysis, cumulative present value of net returns for organic systems (US$3933 to 5446 ha -1, 2000 to 2005; US$2653 to 2869 ha -1, 2000 to 2002) were always substantially greater than for the conventional systems (US$1309 to 1909 ha -1, 2000 to 2005; US$634 to 869 ha -1, 2000 to 2002). With price premiums, Org2 had greater net returns but also greater variability of returns and economic risk across all years than all other systems, primarily because economic success of this short rotation was highly dependent on the success of soybean, the crop with the highest returns. Soybean yield variability was high due to the impact of weather on the success of weed control in the organic systems. The longer, more diverse Org4+ rotation had the lowest variability of returns among organic systems and lower economic risk than Org2. With no organic price premiums, economic returns for corn and soybean in the organic systems were generally lower than those for the conventional systems due to lower grain yields in the organic systems. An exception to this pattern is that returns for corn in Org4+ were equal to or greater than those in NT in four of six years due to both lower production costs and greater revenue than for Org2 and Org3. With no organic premiums, present value of net returns for the full rotations was greatest for NT in 4 of 6 years and greatest for Org4+ the other 2 years, when returns for hay crops were high. Returns for individual crops and for full rotations were, in general, among the lowest and economic risk was, in general, among the highest for Org2 and Org3. Results indicate that Org4+, the longest and most diverse rotation, had the most stable economic returns among organic systems but that short-term returns could be greatest with Org2.
  • Authors:
    • Hedtcke, J. L.
    • Posner, J. L.
    • Chavas, J. P.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 2
  • Year: 2009
  • Summary: This article, the second in a series looking at the Wisconsin Integrated Cropping Systems Trial (WICST), reports on the profitability of six conventional and organic systems, with a focus on net returns and associated risk exposure. Several pricing scenarios were compared to evaluate the impact of government programs and organic price premiums. When net return estimates are made using only neighboring elevator prices (no government programs or organic price premiums), we found that the no-till corn-soybean system [ Zea mays L. and Glycine max (L.) Merr.] was the most profitable grain system, and management intensive rotational grazing (MIRG) the most profitable forage system. When government programs and organic price premiums are included, returns increased by 85 to 110% for the organic grain system corn-soybean-wheat+red clover ( Triticum aestivum L.+ Trifolium pratense L.) and 35 to 40% for the organic forage system [companion seeded alfalfa with oat+field pea ( Medicago sativa L., Avena sativa L., and Pisum sativum L.), hay, and then corn]. This places both organic systems with higher returns than any of the Midwestern standards of no-till corn-soybean, continuous corn, or intensive alfalfa production. Also, the results indicate how risk exposure varied across systems. Interestingly, taking risk into consideration did not drastically affect the ranking among those systems. Our analysis shows that, under the market scenarios that prevailed between 1993 and 2006, intensive rotational grazing and organic grain and forage systems were the most profitable systems on highly productive land in southern Wisconsin.
  • Authors:
    • Baker, B.
  • Source: Proceedings of the 5th Organic Seed Growers Conference, Salem, Oregon, USA
  • Year: 2008
  • Summary: The market for organic seed poses a great opportunity for both organic producers who want to diversify into new crops as well as for seed producers who want to enter into the rapidly growing organic market. While organic standards in the United States require the use of organic seed, organic producers are not able to find organic seed in sufficient quantity and of suitable quality to meet their production needs. Because commercial availability must be evaluated as part of the certification process, the certifying agents play an important role in assessing both the supply and demand for organic seed. Certifying agents were surveyed to identify how they assess commercial availability, what information resources are used, and what crops and varieties are considered commercially unavailable. More research is needed to forecast organic seed demand and overcome production obstacles.
  • Authors:
    • Mbuya, O.
    • Chase, C.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 2
  • Year: 2008
  • Summary: Twelve winter cover crops were planted in Citra and Live Oak, FL, in 2004, to evaluate their potential for use as living mulches in organic vegetable production: black oat, rye, annual ryegrass, hard fescue, two cultivars of white clover, berseem clover, crimson clover, subterranean clover, arrowleaf clover, barrel medic, and a hybrid disc * strand medic cultivar. The best canopy development and weed suppression occurred with black oat, rye, and annual ryegrass. In 2005, black oat, two rye cultivars, and annual ryegrass were evaluated as living mulches in broccoli at Citra and Live Oak, using organic production methods. 'Florida 401' (FL 401) rye was tallest, black oat was intermediate, and 'Wrens Abruzzi' (WA) rye and 'Gulf' ryegrass were of similar height and were the shortest living mulches. Biomass harvested at 12 and 13 wk after planting at Citra and Live Oak, respectively, was greatest with FL 401 rye. At Live Oak, the three other mulches had similar amounts of biomass; however, at Citra, black oat biomass was greater than that of WA rye, and biomass of ryegrass was lowest. The greatest weed infestation occurred with the weedy control. Weed biomass was highest with the weedy control, intermediate with ryegrass, and lowest with rye and black oat. However, the biomass of the weedy control was lower than that of the living mulches plus any associated weeds. Marketable broccoli yield was highest with the weed-free control. Yields with black oat, WA rye, and ryegrass were similar to that of the weedy control, whereas yield with the FL 401 rye was lower than with the weedy control. Suppression of living mulches by mowing at 3 and 7 wk after planting had no effect on broccoli growth or yield.
  • Authors:
    • Wolfe, M.
    • Boyd, H.
    • Haigh, Z.
    • Jones, H.
    • Clarke, S.
  • Source: Cultivating the future based on science. Volume 1: Organic Crop Production. Proceedings of the Second Scientific Conference of the International Society of Organic Agriculture Research (ISOFAR), held at the 16th IFOAM Organic World Conference in Cooperatio
  • Year: 2008
  • Summary: Two seasons (2005/06 and 2006/07) of field experiments which aimed to study the suitability of new and established husked oat varieties, variety mixtures and a husked oat population for organic systems were established at two sites in the west and east of the UK. The ground cover and leaf area indices of the varieties had significant effects on final yields in the 2005/06. Mixtures generally yielded similarly to the means of component varieties but the mixtures in 2005/06 and 2006/07 had 25% and 18% less disease, respectively, than the average of the component varieties at one site.
  • Authors:
    • Pridham, J. C.
    • Entz, M. H.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 5
  • Year: 2008
  • Summary: The success of organic wheat ( Triticum aestivum L.) production can be severely inhibited by weed and disease pressures. This study sought to determine the effectiveness of wheat intercrop mixtures in suppressing weeds and diseases and increasing grain yield and net return. Field experiments were conducted on organically managed land in 2004 and 2005 and three representative intercrop systems were tested: wheat with other cereals [oats ( Avena sativa L.), barley ( Hordeum vulgare L.), and spring rye ( Secale cereale L.)]; wheat and noncereal seed crops (flax [ Linum usitatissimum L.], field pea [ Pisum sativum L.], oriental mustard [ Brassica juncea L.]); and wheat and cover crops (red clover [ Trifolium pratense L.], hairy vetch [ Vicia villosa L.], annual ryegrass [ Lolium multiflorum Lam.]). The cereal intercrop systems provided no consistent yield benefit over wheat monocultures. Results from noncereal-wheat intercrops were variable. Wheat-flax reduced the wheat crop to unacceptable levels but was capable of reducing wheat flag leaf disease levels. Wheat-field pea resulted in the lowest disease levels, yet had inconsistent yields, and more weeds than wheat monoculture. Wheat-mustard did not reduce weeds or diseases, but it was capable of high grain yields and net returns, though usually hampered by flea beetle ( Phyllotreta cruciferae) attack. The effect of cover crops on wheat was affected by environment. Wheat-red clover and wheat-hairy vetch did demonstrate the ability to maintain high wheat grain yield in certain site-years. In conclusion, wheat intercrop mixtures provided little short-term benefit over monoculture wheat in this study.