Research Article
Does growing Canadian Western Hard Red Spring wheat under organic management alter its breadmaking quality?
- H. Mason, A. Navabi, B. Frick, J. O'Donovan, D. Niziol, D. Spaner
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 157-167
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Canadian Western Hard Red Spring (CWRS) wheat is recognized as premium quality wheat, ideal for breadmaking due to its superior milling qualities, baking characteristics and protein content. Organic wheat production is becoming more prevalent in Canada, due to increasing consumer demand for organic wheat products. Differences may exist in the baking and milling quality of wheat grown under conventional and organic management, a result of the dissimilarity between organic and conventional soil and crop management practices. Five CWRS cultivars released from 1885 to 1997 were grown under conventional and organic management and were assessed for their breadmaking potential. Several traits were investigated, including test weight, protein content, flour yield, kernel hardness and several mixograph parameters. Test weight was higher under conventional management, while no differences in protein content were observed between organic and conventionally grown wheat. Higher sodium dodecyl sulfate sedimentation (SDSS) volume, a reflection of gluten strength, was observed under conventional management, while there was a trend towards higher dough strength under organic management. Cultivars differed in grain protein, flour yield, kernel hardness and mixograph parameters, with Park and McKenzie superior to the others, particularly Red Fife, a much older cultivar. Management×cultivar interaction effects suggest that cultivars exhibit somewhat different baking characteristics when grown in the two management systems. There was no evidence that older cultivars (developed prior to the widespread use of pesticides and fertilizers) are better suited, in terms of breadmaking quality, for organic production.
Crop and cattle responses to tillage systems for integrated crop–livestock production in the Southern Piedmont, USA
- A.J. Franzluebbers, J.A. Stuedemann
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 168-180
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Integration of crops and livestock has the potential to provide a multitude of benefits to soil and water conservation and nutrient cycling efficiency, while reducing economic risk and increasing profitability. We conducted a field study from May 2002 to October 2005 to determine crop and cattle responses to three management factors on a Typic Kanhapludult in Georgia, USA. Summer grain/winter cover [sorghum (Sorghum bicolor L. Moench) or corn (Zea mays L.)/rye (Secale cereale L.)] and winter grain/summer cover [wheat (Triticum aestivum L.)/pearl millet (Pennisetum glaucum L. R. Br.)] were managed with either conventional tillage (CT) or no tillage (NT) and with or without cattle grazing of cover crops. All crops were successfully established, irrespective of tillage and cover crop management. Although pearl millet was often lower in the plant stand with NT than with CT, plants compensated with greater biomass on an area basis. Across years, grain yield of sorghum (1.9 Mg ha−1 during three seasons) and corn (7.3 Mg ha−1 in one season) was 25% greater under NT than under CT when the cover crop was not grazed. Wheat grain yield (2.7 Mg ha−1 during three seasons) was unaffected by tillage and cover crop management. Unharvested stover production of summer grain crops was greater with NT than with CT (6.5 versus 4.1 Mg ha−1; P<0.001). Grazing rye rather than allowing it to accumulate as surface residue reduced summer grain yield 23% and reduced standing grain-crop dry matter 26% under NT, but had no effect under CT. In contrast, grazing pearl millet rather than allowing it to accumulate as surface residue increased wheat standing dry matter yield by 25±14% (mean±standard deviation among 3 years and two tillage systems). Ungrazed cover crop production was greater under NT than under CT for rye (7.0 versus 6.0 Mg ha−1; P=0.03) and pearl millet (10.2 versus 7.6 Mg ha−1; P=0.01). Calf daily gain was either greater or tended to be greater under NT than under CT on rye (2.27 versus 2.09 kg head−1 d−1; P=0.15) and pearl millet (2.05 versus 1.81 kg head−1 d−1; P=0.05). Total cattle gain per grazing season was either greater or tended to be greater with NT than with CT on rye (350 versus 204 kg ha−1; P=0.01) and pearl millet (324 versus 277 kg ha−1; P=0.15). Net return over variable costs was greater with grazing than without grazing of cover crops (US$302 versus −US$63 ha−1; P<0.001). Livestock grazing of cover crops had variable effects on subsequent crop production, but increased economic return and diversity overall. Therefore, an integrated crop–livestock production system with conservation tillage is recommended as a viable option for producers to diversify farming operations to avoid risk, improve ecological production of crops, and potentially avoid environmental damage from soil erosion and nutrient loss.
Hedgerow barriers and other reduced-risk controls for managing Oriental fruit moth, Grapholitha molesta (Busck) (Lepidoptera: Tortricidae) in apples
- Carlos Garcia-Salazar, Larry J. Gut, Mark E. Whalon
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 181-188
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Management of Oriental fruit moth, Grapholitha molesta (Busck), in apple using an ‘Enhanced Integrated Pest Management (IPM)’ program comprised of a hedgerow barrier, pheromone-based mating disruption and reduced-risk [non-organophosphorous (OP) or carbamate] insecticides was investigated over a 5-year period. The barrier was comprised of a planting of three rows of hybrid poplar, Populus deltoides Bartr.×Populus nigra L., one row of Italian alder, Alnus cordata L. (nectar reward), and one row of white pine, Pinus strobus L. The hedgerow completely surrounded the perimeter of the apple orchard and was treated with garlic and a low rate of pyrethroid insecticide in 4 of the 5 years. The Enhanced IPM program significantly reduced G. molesta populations as measured by moth captures in pheromone traps. Captures of G. molesta were significantly higher in apple orchards treated with OP and carbamate insecticides, ‘Conventional IPM’, and either not surrounded by the hedgerow or with the barrier present but not treated with the repellent compounds. To explain these differences in G. molesta control, and the potential non-lethal effect of hedgerow barriers on G. molesta orchard colonization, we studied the adult vertical movement in a traditional unsprayed standard apple orchard at three different heights: 0.95, 1.95 and 3.20 m, respectively. In the overwintering generation at a height of 0.95 and 1.95 m, the mean number of moths captured per sampling period was 14.64 and 14.84, respectively, and only 2.95 at 3.20 m. However, the number of individuals captured in the second and third generations was not significantly different at the three different heights. Fruit damage evaluated before ‘June drop’ closely corresponded to the distribution of moths captured during the overwintering generation. Fruit damage at a height of 1.95 and 3.20 m was 5.8 and 3.5%, respectively. These results indicated that G. molesta is a weak flyer and that hedgerow barriers exerted some influence in the colonization of the orchard by limiting the free movement of adults from the overwintering generation. Thus, hedgerow barriers seem to limit early migration and establishment of G. molesta in the orchard. This in turn may reduce the size of the following generations and makes subsequent control easier under the Enhanced IPM program.
A multi-criteria evaluation of the environmental performances of conventional, organic and integrated olive-growing systems in the south of Spain based on experts' knowledge
- Carlos Parra-López, Javier Calatrava-Requena, Tomás de-Haro-Giménez
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 189-203
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The medium to long-term environmental performances of organic, integrated and conventional olive-growing systems in the average conditions of the south of Spain are evaluated and compared with respect to soil erosion, soil fertility, rational use of irrigation water, water contamination, atmospheric pollution and biodiversity, based on experts’ knowledge. The aim of the research was to test the common implicit assumption of environmental superiority of the two alternative farming systems over the conventional system. For this purpose, the Analytic Hierarchy Process (AHP), a widely used multi-criteria decision-making tool, has been implemented. AHP enables us to deal with complex decision-making problems with multiple criteria, stakeholders and decision-makers, high uncertainty and risk, such as in the case of multi-criteria environmental comparison of alternative farming systems. Twenty experts in olive production, clustered into three groups according to their professional field of interest, were involved in the analysis. The utilization of experts' knowledge is justified when information relevant for urgent decision-making is not available, is partial or is time and resource demanding, and a holistic perspective is required. Indexes and procedures are proposed for group decision-making, to detect variation in expert opinions and differences between alternative systems' performances. Despite bias in the judgments of the groups of experts in some topics, results confirm the holistic environmental superiority of organic and integrated alternatives over the conventional olive system in Andalusia in the medium to long-term. The results represent a scientific base to justify and endorse institutional support regarding the promotion and implementation of organic and integrated olive-growing systems in the region, which are likely to result in greater social welfare.
Vegetable crop emergence and weed control following amendment with different Brassicaceae seed meals
- A.R. Rice, J.L. Johnson-Maynard, D.C. Thill, M.J. Morra
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 204-212
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Brassicaceae seed meals produced through the oil extraction process release biologically active glucosinolate secondary products and may be useful as a part of biological weed control systems. Before meal can be used most efficiently, recommendations for suitable planting dates that maximize weed control but reduce crop injury must be determined. Our objectives were to determine the impact of 1 and 3% (w/w) meal applications of Brassica napus L. (canola), Brassica juncea L. (oriental mustard) and Sinapis alba L. (yellow mustard) on crop emergence and weed biomass in a growth chamber and field study. Results from the growth chamber experiment indicated that lettuce emergence was reduced by at least 75% when planted into 3% S. alba-amended soil earlier than 5 weeks after meal application. After 5 weeks, emergence was not different among treatments. Crop emergence was not reduced by any meal treatment as compared to the no-meal treatment in year 1 of the field study. In year 2, crop emergence in each 1.2-m row was inhibited by all meal treatments and ranged from 16 plants in the 3% B. juncea treatment to 81 plants in the no-meal treatment. The difference between emergence results in year 1 and year 2 is likely due to differing climatic conditions early in the season prior to irrigation, and the method of irrigation used. Redroot pigweed (Amaranthus retroflexus L.) biomass was 72–93% lower in 1% B. juncea and 3% treatments relative to the no-meal control in the first weed harvest of year 1. These same treatments had 87–99% less common lambsquarters (Chenopodium album L.) biomass. By the second weed harvest, redroot pigweed biomass in meal treatments (0.02–1.6 g m−2) was not different from that in the no-meal treatment (0.97 g m−2). Redroot pigweed biomass in 3% B. juncea plots was reduced by 74% relative to the no-meal treatment in the first harvest of year 2. This treatment also reduced common chickweed [Stellaria media (L.) Vill.] biomass by 99% relative to the 1% meal treatments. While pigweed biomass was reduced by 3% B. juncea in the early part of the season, by the second harvest this same treatment had the greatest pigweed biomass. Despite significant variability between years, 3% B. juncea did provide early season weed control in both years. Repeated meal applications, however, may be necessary to control late season weeds. Inhibition of crop emergence appears to be highly dependent on the amount and distribution of water and needs to be further studied in field settings.
An alternative way to evaluate the environmental effects of integrated pest management: Pesticide risk indicators
- Thomas J. Greitens, Esther Day
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 213-222
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This study examines whether pesticide risk indicators can be used to evaluate the environmental effects of pesticide applications within integrated pest management (IPM) projects. Pesticide risk indicators, commonly used in European countries, are mathematical equations that consider data inputs such as application rates, toxicity levels of a pesticide's active ingredient, meteorological data, the soil characteristics of farm fields, and other information to generate potential risk scores for pesticide applications. These potential risk scores represent the best estimate of a pesticide's impact on the surrounding environment. This project analyzed eight pesticide risk indicators, developed throughout Europe and the United States, with two years of pesticide application data from four farms using IPM. This two-year study allowed for a determination of the validity and reliability of pesticide risk indicators. The findings reveal that only three pesticide risk indicators performed consistently and gave valid results. These indicators are: the synoptic evaluation model for plant protection agents (SYNOPS) indicator from Germany, the multi-attribute toxicity factor from the United States, and the environmental impact quotient from the United States. As a result, the authors recommend these three indicators for future research and for IPM evaluative efforts that emphasize the environmental effects of pesticides.
Farm-gate nutrient balance assessment of organic dairy farms at different intensity levels in Germany
- G. Haas, C. Deittert, U. Köpke
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- Published online by Cambridge University Press:
- 08 August 2007, pp. 223-232
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Organic farms are characterized as low external input agro-ecosystems. Currently, some organic dairy farmers feed higher amounts of concentrates and succulent feed, some of which is purchased, to increase the dairy performance of their cows. To assess the environmental impact of this practice, nutrient balances at the farm-gate level of 26 organic dairy farms located in two different regions in Germany were compiled and analysed. The farms are characterized by different production features and feeding intensity levels [0–2.72 t dry matter (DM) of concentrates per cow and year, which was 0–378 g kg−1 milk] yielding 5150–8790 kg milk on average per cow and year. The area- and product (milk)-related farm-gate nutrient budgets for P and K are almost balanced [mean −3 kg P ha−1, range (R): −14 to 4 kg P ha−1; −0.5 g P kg−1 milk, R: −2.8 to 0.9 g P kg−1 milk and 1 kg K ha−1, R: −13 to 15 kg K ha−1; 0.1 g K kg−1 milk, R: −2.4 to 3.9 g K kg−1 milk]. The N surplus averages only 43 kg ha−1 (R: 8–85 kg N ha−1) and 8.2 g kg−1 milk (R: 2.1–17.1 g kg−1 milk), but the correlation between the amount of feed purchased on a net basis and N surplus is significant (r=0.56, P=0.003). Average area-related nutrient use efficiency for all farms calculated as the proportion of input to output is high for N (45%), P (164%) and K (91%). The share of nutrient input and output components and correlations between parameters are presented. To classify the results, investigations comparing organic and conventional dairy farming in Europe are listed, indicating an N surplus for organic farms, which is often only half or a third of the surplus of conventional farms. However, intensification in organic dairy farming has, in some cases, significant impacts that need to be assessed to determine its environmental performance and profile.
Yield and fruit quality response of sweet pepper to organic and mineral fertilization
- F.M. del Amor
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- 08 August 2007, pp. 233-238
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Sweet pepper plants were grown in a greenhouse under three different cultivation methods (organic, integrated and conventional farming). During the crop cycle, plant growth and especially yield and fruit quality parameters were monitored to determine the effects of the different fertilization strategies. Plant fresh weight and total leaf fresh weight were progressively reduced, relative to the other treatments, in the organic treatment compared with the conventional, and at the end of the crop cycle these parameters were reduced by 32.6 and 35% respectively. This reduction in growth was directly correlated with plant nitrate concentration and, at the end of the study, nitrate concentration was reduced almost completely in the organic treatment. Despite the important effect on growth, no significant differences in total marketable yield were observed between conventional and organic farming, although integrated farming showed the highest yield in the extra and first class fruit categories. Organic farming increased antioxidant activity but reduced both chlorophylls and β-carotene. Fruit firmness, pericarp thickness, pH and total soluble solids content showed higher values with the organic method, but these differences were not significant with respect to the conventional method. Our results show the advantages of the organic fertilization, from both environmental and economic perspectives, if proper dosage is added to the crop and the demonstrated buffer capacity of these plants, with respect to maintaining yield under nutrient depletion at later stages of development, is taken into account.
Book Review
Farming for Us All: Practical Agriculture and the Cultivation of Sustainability. By Michael Mayerfeld Bell, Susan Jarnagin, Gregory Peter, and Donna Bauer. 2004. Pennsylvania State University Press, PA, USA. 299 p. US$22.50, ISBN 0271023872, paperback.
- Michael Gertler, Dr
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- 08 August 2007, pp. 239-240
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