Cross-Disciplinary Analysis of the On-Farm Transition from Conventional to Organic Vegetable Production

This farm-scale analysis of the three-year transition to organic from conventional vegetable production tracked the changes in crop, soil, pest and management on two ranches (40 and 47 ha) in the Salinas Valley, California. Many small plantings of a diverse set of cash crop and cover crop species were used, as compared to only a few species in large monocultures in conventional production. The general trends with time were: increase in soil biological indicators, low soil nitrate pools, adequate crop nutrients, minor disease and weed problems, and sporadic mild insect damage. Some crops and cultivars consistently produced higher yields than others, relative to the maximum yield for a given crop. Differences in insect and disease damage were also observed. These results support the value of initially using a biodiverse set of taxa to reduce risk, then later choosing the best-suited varieties for optimal production. The grower used some principles of organic farming (e.g., crop diversity, crop rotation, and organic matter management), but also relied on substitution-based management, such as fertigation with soluble nutrients, initially heavy applications of organic pesticides, and use of inputs derived from off-farm sources. The organic transition was conducive to both production goals and environmental quality

Effective monitoring of agriculture: a response

The development of effective agricultural monitoring networks is essential to track, anticipate and manage changes in the social, economic and environmental aspects of agriculture. We welcome the perspective of Lindenmayer and Likens (J. Environ. Monit., 2011, 13, 1559) as published in the Journal of Environmental Monitoring on our earlier paper, “Monitoring the World's Agriculture” (Sachs et al., Nature, 2010, 466, 558–560). In this response, we address their three main critiques labeled as ‘the passive approach’, ‘the problem with uniform metrics’ and ‘the problem with composite metrics’. We expand on specific research questions at the core of the network design, on the distinction between key universal and site-specific metrics to detect change over time and across scales, and on the need for composite metrics in decision-making. We believe that simultaneously measuring indicators of the three pillars of sustainability (environmentally sound, social responsible and economically viable) in an effectively integrated monitoring system will ultimately allow scientists and land managers alike to find solutions to the most pressing problems facing global food security

Short-term Effects of Grassland Set-Asides on Soil Properties in the Fraser River Delta of British Columbia

Grassland set-asides (GLSA) in the Fraser River delta are fields that are taken out of crop production and seeded with a mixture of grasses and legumes for one to four years. During this time, the farmer is compensated with a cost-share payment to recover a portion of the financial returns that could have been earned from cash crops. The objectives of this study were to (i) evaluate the effects of GLSA on soil properties during the initial two seasons of enrollment, (ii) determine how GLSA effects differ between fields that were considered productive and unproductive, and (iii) identify soil baseline indicators and preliminary soil thresholds for predicting GLSA vegetation responses. Out of eight fields entering the program, two were considered to be unproductive and exchangeable sodium had the strongest negative relationship to GLSA aboveground biomass (r= -0.61, P=0.0002). During the second season of GLSA establishment, the mean weight diameter of water-stable soil aggregates was consistently higher in productive GLSAs than paired annual crop rotation (ACR) fields, being 21% higher in April, 14% in July, and 19% in September after crop harvest. After two seasons of GLSA enrolment, both aeration porosity and bulk density were improved by GLSA relative to ACR fields with aeration porosity being 24% greater and bulk density 7% lower in GLSA. The results suggest that GLSA rotations in productive agricultural fields within the Fraser River delta provide an alternative to continued ACR that can improve soil structure and reduce compaction after only two seasons of establishment.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Evaluating ecosystem service trade-offs and synergies from slash-and-mulch agroforestry systems in El Salvador

Peer Revie

Using agroecology to stimulate the greening of agriculture in China: a reflection on 15 years of teaching and curriculum development

Even though worldwide research and teaching in Agroecology blossomed in the 1980s, until recently, the development of Agroecology in China has been constrained by technical, cultural and economic considerations. The delay in the assimilation of Agroecology, as a science, a practice and a movement, has resulted in the discipline of Agroecology in China lacking the holistic, interdisciplinary approaches needed to respond to current global and regional agricultural challenges. There is a need to redefine Agroecology both as a critical discipline and as a pedagogical approach. By using an ecology-oriented systematic approach to integrate education and research, a reframed Agroecology is proposed; this is based on a re-imagined, holistic consideration of the hierarchy of agroecosystems. The practical experience of a 15-year international team-taught Agroecology education programme among participants from Canada and China has helped refine disciplinary classifications, both from horizontal and vertical hierarchies. There are evolving impacts of this experiment in Sino-Canadian cooperation in Agroecological research and education; they include a new generation of highly trained agroecologists prepared to act across inter-related disciplines; the alignment of Chinese universities to international agricultural curricula and a better- informed policy-making process towards greening agriculture in China

Predicting carbon benefits from climate-smart agriculture: Highresolution carbon mapping and uncertainty assessment in El Salvador

Peer Revie