Research Papers
Sweet corn hybrid tolerance to weed competition under three weed management levels
- R.A. Boydston, M.M. Williams II
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- Published online by Cambridge University Press:
- 23 June 2015, pp. 281-287
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Nearly all commercial sweet corn fields contain weeds that escaped management and, therefore, sweet corn often suffers yield losses due to weed competition. For this reason, field trials were conducted from 2009 to 2011 near Prosser, WA and Urbana, IL to evaluate the responses of weeds and four sweet corn hybrids to three levels of weed management; weed free, high intensity cultivation (HC), and low intensity cultivation (LC). Weed management level had the greatest impact on early season weed densities and HC reduced final weed biomass more than LC in 2 of 4 site-years. Two taller sweet corn hybrids with greater leaf area suppressed final weed biomass more than two shorter hybrids with less leaf area in 3 of 4 site-years. When grown with less intense weed management that resulted in more weeds, taller sweet corn hybrids with greater leaf area maintained yields better than shorter, less competitive sweet corn hybrids. Utilizing hybrids with greater tolerance to weeds and greater ability to suppress weeds could be a valuable component of an integrated weed management system.
The effectiveness of flame weeding and cultivation on weed control, yield and yield components of organic soybean as influenced by manure application
- Strahinja Stepanovic, Avishek Datta, Brian Neilson, Chris Bruening, Charles Shapiro, George Gogos, Stevan Z. Knezevic
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- Published online by Cambridge University Press:
- 22 June 2015, pp. 288-299
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Propane flaming in combination with cultivation could be a potential alternative tool for weed control in organic soybean production. Field experiments were conducted at the Haskell Agricultural Laboratory of the University of Nebraska-Lincoln (UNL), Concord, NE in 2010, 2011 and 2012 to determine the level of weed control and the response of soybean grain yield and its components to flaming and cultivation within two fertility regimes (FRs) (with and without manure) utilizing flaming equipment developed at the UNL. The treatments included: weed-free control, weedy season-long and different combinations of banded flaming (intra-row), broadcast flaming and mechanical cultivation (inter-row). The treatments were applied at VC (unfolded cotyledon) and V4–V5 (4-leaf–5-leaf) growth stages. Propane doses were 20 and 45 kg ha−1 for the banded and broadcast flaming treatments, respectively. The data were collected for visual ratings of crop injury and weed control at 7 and 28 days after treatment (DAT) at V4–V5 growth stages, weed dry matter at 60 DAT, crop yield and yield components. The annual application of 101 t ha−1 manure did not alter weed community or influence the effectiveness of weed management treatment; however, it decreased soybean yield by 0.25 t ha−1 through an increased weed biomass of 0.16 t ha−1. The weed-free control plots yielded 4.15 t ha−1. The combination of mechanical cultivation and banded flaming applied twice (at VC and V4–V5) was the best treatment resulting in 80–82% weed control and 6–9% crop injury at 28 DAT and 3.41–3.67 t ha−1 yield. Cultivation conducted twice provided only 19% weed control at 28 DAT and 1.75 t ha−1 yield. Soybean plants recovered well after all flaming treatments, with the exception of broadcast flaming conducted twice (28% crop injury at 28 DAT). Combining flaming with cultivation has a potential to effectively control weeds in organic soybean production across a range of FRs.
Influence of different soil management practices on ground-flora vegetation in an almond orchard
- M. Fracchiolla, M. Terzi, L. Frabboni, D. Caramia, C. Lasorella, D. De Giorgio, P. Montemurro, E. Cazzato
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- Published online by Cambridge University Press:
- 21 July 2015, pp. 300-308
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This paper reports a survey on the weed flora and seed bank in an almond orchard sited in Apulia region (Southern Italy), where the following soil management practices have been compared for over 30 yrs: no-tillage, keeping the soil totally weed-free throughout the year by using pre-emergence herbicides to prevent plant emergence or post-emergence herbicides in case of weeds already emerged; no-tillage, with post-emergence herbicides; no-tillage, with mowing of natural weed flora in spring; cover cropping, with faba bean sown in November and green manured in springtime; conventional soil tillage. The different management techniques influenced significantly the weed flora in experimental plots, both in terms of quantity and quality. The seed bank was clearly impoverished after the long-term applications of pre-emergence herbicides, both in terms of richness and of diversity. During the fall period, the plots of conventional tillage or pre-emergence herbicides had less natural ground-flora than the others. During springtime, prior to the sward control practices, the plots treated by foliar herbicides or mowing had the highest total weed cover. We conclude that post-emergence weed control by mowing or using chemical herbicides or the green manure of the cover crop may be proposed to reduce impact to the soil and to promote the growth of abundant and sufficiently diversified and balanced flora. If appropriately managed, this flora can provide potential ecological services, without competing with the orchard, as suggested by the literature. During the autumn, natural flora can uptake soil nitrogen thus preventing leaching in the rainy season. In springtime, after the sward has been destroyed, natural flora can supply a substantial amount of biomass to the soil. Indicator species analysis was also used to find the species characterizing each treatment and some of their combinations. Weeds belonging to the Poaceae botanical family were significantly associated with post-emergence herbicides and mowing treatments. These species produce a substantial amount of biomass and have bunched roots; consequently, they supply beneficial effects by improving porosity and structure of the soil and reducing erosion hazard.
Living mulch cover crops for weed control in small-scale applications
- Anne Pfeiffer, Erin Silva, Jed Colquhoun
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- Published online by Cambridge University Press:
- 02 September 2015, pp. 309-317
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A primary challenge of managing vegetable production on a small land base is the maintenance and building of soil quality. Previous studies have demonstrated the benefits of cover crops for improved soil quality; however, small growers struggle to fit cover crops into rotations. Small-scale growers with limited available land are under significant pressure to maximize their saleable yield and often work to maximize output by using intensive cropping practices that may include both early and late season crops, thus limiting the typical shoulder season windows in which cover crops can be grown. In-season living mulches may be an effective strategy to provide small-scale growers the benefits of cover crops with less land commitment than cover crops used in typical rotations. However, research on living mulches is generally not suited to small-scale organic production systems due to the typical reliance on chemical herbicide to suppress mulches. An experiment was designed with the goal of evaluating living mulch systems for space-limited organic vegetable production. In a 2-year study, four living mulch crops (buckwheat (Fagopyrum esculentum), field pea (Pisum sativum), crimson clover (Trifolium incarnatum) and medium red clover (Trifolium pratense)) and a cultivated control with no mulch cover were planted in early spring each year. Snap beans (Phaseolus vulgaris var. Tavera), transplanted bell peppers (Capsicum annuum var. Revolution), and transplanted fall broccoli (Brassica oleracea var. Imperial) were then planted directly into living mulches. During each summer growing season, living mulches and weeds were mown between-rows and hand-weeded in-row approximately every 10–14 days as needed for management. Labor times for mowing and cultivation were found to be higher in all treatments relative to the cultivated control. An inverse relationship between living mulch biomass and weed biomass was observed, demonstrating that living mulches may contribute to weed suppression. However, lower vegetable yields were seen in the living mulch treatments, most likely due to resource competition among vegetables, living mulches and weeds. High pre-existing weed seedbank and drought conditions likely increased competition and contributed to reduced vegetable yield.
Investment behavior and status quo bias of conventional and organic hog farmers: An experimental approach
- Daniel Hermann, Oliver Mußhoff, Katrin Agethen
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- Published online by Cambridge University Press:
- 22 July 2015, pp. 318-329
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Despite the economic benefits of organic farming, the conversion rates to this production method are low. The reasons for this reluctance are largely unknown; however, understanding this behavior is important for policy recommendations. Therefore, we experimentally investigate and compare the investment behavior of organic and conventional hog farmers. We examine whether the investment behavior depends on the organic or conventional farmers’ status quo of their production method. Our results show that farmers are more reluctant to invest in production methods they are not currently using compared with those already in use on their farm. Conventional, more risk-averse farmers, and those farmers holding a university degree, invest later in a hog barn. The results provide evidence that investment decisions depend on the status quo production method of a farmer and, thus, reveal that current subsidy structures may be ineffective in encouraging farmers to invest in production methods they are not currently using on their farms.
The potential of surplus grass production as co-substrate for anaerobic digestion: A case study in the Region of Southern Denmark
- Ane Katharina Paarup Meyer, Caroline Schleier, Hans-Peter Piorr, Jens Bo Holm-Nielsen
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- Published online by Cambridge University Press:
- 20 July 2015, pp. 330-349
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This paper presents an assessment of the surplus grass production in the Region of Southern Denmark, and the perspectives of utilizing it in local biogas production. Grass production represents a significant role in the Danish agricultural sector. However, statistical data show an excess production of averagely 12% in the period 2006–2012. Based on spatial analyses and statistical data, the geographical distribution of grass production and consumption was estimated and mapped for the Region of Southern Denmark. An excess production of grass was estimated for several of the municipalities in the Region of Southern Denmark, but the excess production was found to be quite sensitive to the management practice of the grass fields and the productivity of the grass. The yields of excess grass estimated in the sensitive and conservative scenario were found to be sufficient to serve a sole co-substrate in 2–8 biogas plants using animal manure as primary feedstock. The yields in the intensive scenario were assessed to be sufficient to serve a sole co-substrate in 8–16 biogas plants. Alternatively, at least 31% of the regionally produced maize which is exported to the biogas sector could annually be substituted by methane produced from the production of excess grass. The intensive scenario was estimated to have significantly higher grass yields than the sensitive and conservative scenario. The environmental impacts of intensified agricultural management should, however, be assessed carefully in order to ensure that the ecosystems are not increasingly being burdened. The potential of utilizing residual grass for energy production in the region or as an alternative to the maize exported to Northern Germany, was concluded to seem as a promising possibility for a sustainable development of the regional biogas sector. Furthermore, it could provide incentives for establishing new biogas plants in the region and thereby increase the share of manure being digested anaerobically, which could help extrapolate the environmental and climate related benefits documented for the use of digested animal manure as fertilizer on agricultural land.
Conversion of rural abattoir wastes to an organic fertilizer and its application in the field cultivation of tomato in India
- Malancha Roy, Rimi Das, Anupam Debsarcar, Pradip Kumar Sen, Joydeep Mukherjee
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- Published online by Cambridge University Press:
- 12 August 2015, pp. 350-360
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Sophisticated capital intensive waste-recycling technologies are unviable in small rural abattoirs in India due to low volume of wastes (principally blood and rumen digesta) generated and lack of infrastructural facilities. We report recycling of slaughterhouse wastes as an organic fertilizer, ‘bovine-blood-rumen-digesta-mixture’ (BBRDM). Bovine blood and rumen digesta were mixed in 3:1 ratio in a metallic container, boiled and stirred continuously till the mixture was largely free of water. The mass was sun-dried for 3 days to obtain the final product. BBRDM was applied for field cultivation of tomato (Lycopersicon esculentum L., local variety ‘Patharkuchi’) in West Bengal state (India) during 2012–13 and 2013–14. We compared tomato yields obtained with BBRDM (N:P2O5:K2O 30.36:1:5.75) and conventional inorganic fertilizers [diammonium phosphate (DAP), N:P2O5:K2O 18:46:0 + potash, N:P2O5:K2O 0:0:44]. BBRDM was applied at a higher rate compared with DAP + potash to meet the farmers’ desire for enhanced yields. 75 kg ha−1 was applied at the 2nd week while 150 kg ha−1 was applied at the 8th week after transplantation. Yields (total fruit weight) obtained from BBRDM-treated plants were higher in comparison with DAP + potash-fertilized plants by 46–48% as the former supplied 2.5 times more nitrogen (N) than the latter. The partial factor productivity of DAP + potash was 73–76% higher than BBRDM. Conversely, as BBRDM was produced through local entrepreneurship from slaughterhouse wastes, the cost of this organic product would be expected to be much lower than the commercial inorganic fertilizer. Furthermore, application of BBRDM negates the environmental cost of treating slaughterhouse effluent. Considering the same cost of applying 225 kg fertilizer ha−1, higher yield with BBRDM should result in greater potential revenue for the farmer compared with yields with DAP + potash. The C/N ratio of BBRDM is 4.8, having relatively high N content. Accordingly, rapid release of plant-available N was observed in BBRDM-fertilized soils. The temporal increase in soil NH4+may be attributed to lack of soil N immobilization. Local farmers are willing to accept the new fertilizer as a substitute for currently used chemical fertilizers.
Cover crop and tillage intensities alter ground-dwelling arthropod communities during the transition to organic production
- Randa Jabbour, Tara Pisani-Gareau, Richard G. Smith, Christina Mullen, Mary Barbercheck
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- Published online by Cambridge University Press:
- 12 August 2015, pp. 361-374
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We conducted a cropping systems experiment in central Pennsylvania, USA, to determine the effects of initial cover crop species and soil management on the abundance and composition of the ground-dwelling arthropod community. We hypothesized that we would detect legacy effects of the cover crops planted in year 1 of a 3-yr crop sequence on the arthropod community in the subsequent 2 yrs, and that these effects would be influenced by the intensity of tillage. We compared four systems in a factorial combination of perennial sod and legumes or annual cereal grain and legume as initial cover crops and moldboard or chisel plow tillage implemented in soybeans followed by maize in the subsequent 2 yrs. The entire experiment was initiated twice in adjacent locations, starting in 2003 (Start 1) and 2004 (Start 2). We quantified soil arthropod activity-density and community composition and identified all arthropods to order or family, and the ground and tiger beetles (Coleoptera: Carabidae) to species. In Start 1, but not Start 2, arthropod activity-density increased with each year following implementation of organic management. We observed few legacy effects of cover crop or tillage intensity on arthropod activity-density. The composition of the soil arthropod community was primarily defined by the initial cover crop in the first year, and by the interaction between cover crop and tillage intensity in the second and third year. A legacy effect associated with a yr-1 cover crop of cereal rye was observed for Scarabaeidae beetles and Formicidae (ants) in yr 2 and Carabidae beetles in yr 3 of Start 1, but not Start 2. Weed indicators contributed significantly to the variation in the soil arthropod community that was explained by the environment in yr 2 in Start 1, and in yr 3 in both Starts. Our observations support the concept that both immediate and legacy effects of management shape arthropod communities during the organic transition period, suggesting that transitioning systems could be managed in ways that conserve or enhance natural enemy populations.
Spatial analysis of the participation in agri-environment measures for organic farming
- Fabio Boncinelli, Fabio Bartolini, Gianluca Brunori, Leonardo Casini
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- Published online by Cambridge University Press:
- 07 September 2015, pp. 375-386
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Support for organic farming is a key strategy of rural development policies in several countries. This paper studied the spatial pattern of participation in agro-environmnetal policy the policies designing to foster diffusion of organic farming. The ultimate goal is to investigate the impact of local factors for improving the policy targeting. Indicators of spatial association and a spatial econometrics model were performed for the analysis. The results show regional agglomeration effects of the rate of participants to the measures adopted to promote organic farming. In addition, a spatial relation among the farms that obtain public support is found, highlighting that the diffusion of participation is driven mainly by imitation process and external economies of scale.