Kathleen Delate

Organic no-tillage system effects on soybean, corn and irrigated tomato production and economic performance in Iowa, USA

Novel technologies to reduce tillage in organic systems include a no-tillage roller/crimper for terminating cover crops prior to commercial crop planting. The objective of this experiment was to compare: (1) weed management and yield effects of organic tilled and no-tillage systems for corn ( Zea mays L.), soybean [ Glycine max (L.) Merr.] and irrigated tomato ( Lycopersicon esculentum Mill.), using a roller/crimper and two cover crop combinations [hairy vetch/rye ( Vicia villosa Roth/ Secale cereale L.) and winter wheat/Austrian winter pea ( Triticum vulgare L./ Pisum sativum L. ssp. arvense (L.) Poir.)]; and (2) the economic performance of each system. Weed management ranged from fair to excellent in the organic no-tillage system for soybean and tomato crops, with the rye/hairy vetch mulch generally providing the most weed suppression. Corn suffered from low rainfall, competition from weeds and hairy vetch re-growth and, potentially, low soil nitrogen (N) from lack of supplemental fertilization and N immobilization during cover crop decomposition. No-tillage corn yields averaged 5618 and 634 kg ha −1 in 2006 and 2007, respectively, which was 42–92% lower than tilled corn. No-tillage soybeans in 2007 averaged 2793 kg ha −1 compared to 3170 kg ha −1 for tilled soybeans, although no-tillage yields were 48% of tilled yields in the dry year of 2006. Irrigated tomato yields averaged 40 t ha −1 in 2006 and 63 t ha −1 in 2007, with no statistical differences among tillage treatments. Economic analysis for the three crops revealed additional cover crop seed and management costs in the no-tillage system. Average organic corn returns to management were US

Alkamide production from hairy root cultures of Echinacea

1028 and US

Organic Pepper Production Systems Using Compost and Cover Crops

2466 ha −1 greater in the tilled system compared to the no-tillage system in 2006 and 2007, respectively, which resulted mainly from the dramatically lower no-tillage yields. No-tillage soybean returns to management were negative in 2006, averaging US

Identification of light-independent inhibition of human immunodeficiency virus-1 infection through bioguided fractionation of Hypericum perforatum

−14 ha −1 , compared to US

Building a farmer-centered land grant university organic agriculture program: A Midwestern partnership

742 ha −1 for tilled soybeans. However, in 2007, no-tillage soybean returns averaged US

Effect of Organic Pest Management Practices on Apple Productivity and Apple Food Safety

1096 ha −1 . The 2007 no-tillage irrigated tomato returns to management averaged US

The Long-Term Agroecological Research (LTAR) Experiment Supports Organic Yields, Soil Quality, and Economic Performance in Iowa

53,515 compared to US

Transition Strategies for Post-CRP Certified Organic Grain Production

55,515 in the tilled system. Overall, the organic no-tillage soybean and irrigated tomato system demonstrated some promise for reducing tillage in organic systems, but until economic benefits from soil carbon enhancement can be included for no-tillage systems, soil improvements probably cannot offset the economic losses in no-tillage systems. Irrigation could improve the performance of the no-tillage system in dry years, especially if grain crops are rotated with a high-value irrigated tomato crop.

Incorporating native plants into multifunctional prairie pastures for organic cow–calf operations

Hairy root cultures of Echinacea, one of the most important medicinal plants in the US, represent a valuable alternative to field cultivation for the production of bioactive secondary metabolites. In this study, the three most economically important species of Echinacea (Echinacea purpurea, Echinacea pallida, and Echinacea angustifolia) were readily transformed with two strains of Agrobacterium that produce the hairy root phenotype. Transformed roots of all three species exhibited consistent accelerated growth and increased levels of alkamide production. Optimization of the culture of Echinacea hairy roots was implemented to enhance both growth and alkamide production concomitantly. The use of half-strength Gamborg’s B5 medium supplemented with 3.0% sucrose was twice as effective in maintaining hairy root production than any other media tested. The addition of indolebutyric acid increased the growth rate of roots by as much as 14-fold. Alkamide production increased severalfold in response to the addition of the elicitor, jasmonic acid, but did not respond to the addition of indolebutyric acid. Induced accumulation of the important bioactive compounds, alkamides 2 and 8, was observed both in transformed roots and in response to jasmonic acid treatments. The results of this study demonstrate the efficacy of hairy root cultures of Echinacea for the in vitro production of alkamides and establish guidelines for optimum yield.

Socio-cultural aspects of cow–calf operation persistence in a peri-urban county in Iowa

ABSTRACT In a national survey and through statewide focus groups, organic farmers identified pest management and soil fertility as their most critical vegetable research needs. In response, a long- term experiment was established to compare pepper (Capsicum annuum L.) growth, productivity, insect populations, harvest cullage and postharvest weight loss under conventional and organic management. Treatments from the first 3 years (1998 to 2000) consisted of combinations of two synthetic fertilizer and three compost-based certified organic soil amendments. In addition to the compost treatments, effects of a cover crop of hairy vetch (Vicia villosa Roth) and rye (Secale cereale L.) were evaluated in the organic system from 1999 onward. Pepper growth, harvest weight and marketable fruit numbers were similar in conventional and organic production systems from 1998 to 2000 when 112 kg ha−1 N was applied through synthetic fertilizer or compost. Zone-tillage or incorporation of cover crops prior to planting resulted in pepper weights equivalent to compost treatments in 1999, but in zone-tilled plots in 2000, pepper growth was significantly reduced. Corn borer [Ostrinia nubilalis (Hübner)] larval populations were similar in both systems, with beneficial insect populations greater in the organic system in 1999 only. The number of culled peppers due to insect or disease damage was similar in conventional and organic systems in 1998 and 1999, but greater in the synthetic fertilizer plots in 2000. Postharvest weight loss was similar in the compost (112 kg ha−1 N) and synthetic fertilizer treatments in 1999 and 2000 after three to nine weeks in 10°C storage.