Erin M. Silva

Effect of Nectar Composition and Nectar Concentration on Honey Bee (Hymenoptera: Apidae) Visitations to Hybrid Onion Flowers

Abstract Floral nectar characteristics of nine inbred lines of onion (Allium cepa L.) were examined to determine their influence on the attractiveness of the onion flowers to honey bees (Apis mellifera L.). Potassium concentrations and sugar concentrations of the nectar did not significantly correlate with the number of bee visits received by an umbel. The average amount of nectar produced by both the umbels and the individual florets was significantly positively correlated with the number of bee visits. Our results suggest that selection for flowers with high nectar production may lead to a higher rate of pollination of the onion seed crop.

Screening Five Fall-Sown Cover Crops for Use in Organic No-Till Crop Production in the Upper Midwest

Organic no-till systems continue to draw interest from organic producers across the upper Midwest in the United States. Fall-planted cover crops, terminated in the spring through the use of a roller-crimper or a mower, are a key component of these systems. In this study, five different cover crops (hairy vetch, Austrian winter peas, winter rye, winter barley, and winter triticale) were planted in the fall and terminated in the spring in preparation for no-till organic row crop production. This study compared the cover crops through measurements of: a) the amount of biomass produced by the cover crops before termination; b) the weed suppression potential of the cover crops terminated with either a roller-crimper or sickle-bar mower; and c) volumetric soil water content throughout the row crop production season. Biomass production of each of the cover crops differed significantly by variety and by year, ranging from 3.67 to 14.56 Mg DM ha−1. Significant differences in weed densities and weed biomass were also found, with almost complete elimination of weed establishment in the rye treatment in 2011. Roll-crimping and sickle-bar mowing treatments demonstrated similar weed suppression and soil moisture from May through October during 2010 and 2011.

Innovation in urban agricultural practices: Responding to diverse production environments

Although discussion of the role of urban agriculture in developing nations has occurred over the past decade, dialogue relating to urban agriculture in industrialized countries, including the United States (US) has only recently begun to attract significant attention. The unique factors that influence urban agriculture, including limited and non-traditional land access, use of reclaimed soils and alternative growing mediums, local legal and political environments, social and community-based missions, and involvement of non-traditional farmers, create a production system distinct from rural agricultural enterprises. In many cases, specific local environmental and external factors drive urban farms to develop unique innovations for space-intensive production systems, often creating a dominant paradigm for urban farming for a given location. Furthermore, non-production-related organizational goals are often the primary focus of urban agricultural operations, with the food production becoming a secondary objective. In order to address this information gap regarding the status of urban agriculture in the US, our project, centered at the University of Wisconsin-Madison, gathered datathrough site visitsto and interviewsof organizations in sevencities, examining how structural and strategic food system factors shape urban agricultural efforts. A broad range of operations are considered, including diverse business and production models based on both commercial and community-based management strategies and production in parking and vacant lots, warehouses, public land and peri-urban locations. Based on these observations, the unique innovations in space-intensive agricultural production that have arisen in response to urban food system factors are discussed. We conclude with an assessment of the most significant challenges continuing to face urban agriculture.

Seed and Plant Breeding for Wisconsin’s Organic Vegetable Sector: Understanding Farmers’ Needs

Plant breeding and seed issues are of growing importance in organic farming, but more regionally specific information is needed. In 2012, we surveyed Wisconsin organic vegetable growers regarding: a) general characteristics and farm practices; b) challenges in accessing organic seed; c) plant breeding priorities; and d) improving access to appropriate plant breeding and seed systems. Results suggest that growers had more difficulty accessing satisfactory genetics than seed quality, and that seed access was more problematic for growers with larger farming operations. Diverse plant breeding priorities, combined with prevalent variety trialing and seed saving, suggest a good fit with participatory plant breeding.

Living mulch cover crops for weed control in small-scale applications

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.

From the field: A participatory approach to assess labor inputs on organic diversified vegetable farms in the Upper Midwestern USA

Consumer interest in locally grown produce continues to increase in the USA. Small, diversified vegetable farms, including those managed organically, have been important contributors to meet this growing demand for local product. To be profitable in these markets, farmers must be able to appropriately price their products to cover production costs and provide themselves and their employees a living wage. Questions remain, however, as to the most effective method of assessing the cost of production of specific crops on these farms, in part due to the variability in labor inputs associated with diversified farming strategies. This study used a participatory approach to investigate both methodologies for varied widely, with high coefficients of variation calculated for all values, indicating high farm-to-farm variability in labor required for seasonal activities. Farmers reported both challenges with data collection, as well as successes in using data analysis to guide management decisions. This ongoing work highlights the value of collecting farm-specific data for use in cost-of-production determinations.

Cover crop adoption and intensity on Wisconsin’s organic vegetable farms

ABSTRACT Cover crop adoption varies across agroecological contexts, both in terms of the number of farmers using cover crops and in the ways that farmers use them. Most assessments of cover crop adoption treat adoption as a binary variable, rather than as a continuum of practices, and do not use regression analysis to identify the drivers of adoption. In 2014, we surveyed organic vegetable farmers in Wisconsin to assess their use of cover crops in terms of cover crop acreage, species diversity, and complexity of management practices. We also used regression analysis to identify key drivers of cover crop use and assessed farmer and farm characteristics and perceptions of cover crops. Survey results and regression analysis show that cover crops are widely used by Wisconsin’s organic vegetable farmers, but acreage, diversity, and complexity of cover crop use varied and have different explanatory factors. Cover cropping extent is negatively correlated with dependence on vegetable revenue, while cover crop species diversity and complexity are positively linked to more educated and experimental farmers. By using different measures of adoption and regression analysis, we can better understand how and why farmers are using cover crops, providing opportunities for improved adoption through research and policy interventions.

Long-term systems experiments and long-term agricultural research sites: Tools for overcoming the border problem in agroecological research and design

ABSTRACT To most effectively integrate research across scales and disciplines, long-term system experiments (LTSE) can serve as a valuable tool in agroecological studies. In this paper, we discuss the role of LTSE in understanding agroecosystem function, as well as components to effective design these studies to further the implementation of agroecological practices. Further, we describe the contributions of long-term agricultural research sites (LTARs) to LTSE, as places at the crossroad of stakeholders and civil society, agricultural, economic, and social stakes, research and practical questions, and disciplines and methods (if not paradigms). In use ways, LTSEs and LTARs help overcome what we term the border problem of conventional agriculture research. Maintaining LTARs in a world dominated by short-term funding remains a key challenge to support agroecological research in need of multidimensional data, but is essential to address the need for interdisciplinary and transdisciplinary approaches to solve the “wicked problems” facing today’s society.

Time and Technique Studies for Assessing Labor Productivity on Diversified Organic Vegetable Farms

As regional food purchasing continues to gain consumer interest, an increasing number of diversified vegetable farms have emerged to meet market demand. Many of the smalland midscale vegetable farms selling into local markets, however, face continued challenges concerning the financial decision-making and the viability of their operations. Greater understanding of the consequences of financial, labor, and production-management decisions has the potential to improve the longterm success of these farms. In this exploratory work utilizing a comparative case study approach involving 10 diversified vegetable farms, we conducted time and technique studies to assess labor productivity as related to different farm labor and production management decisions. We focused our analysis on three specific activities (transplanting, harvest, and postharvest handling) for five common crops (broccoli, carrots, lettuce, peppers, and squash). Our results showed tremendous farm-tofarm variation in labor productivity, reflecting the diversity of approaches to production and a Rachel J. Weil, Agroecology Graduate Program, Program, University of Wisconsin-Madison; Madison, WI USA;