Building Supportive Networks Among Agricultural Innovators Through a Symposium on Dryland Organic Farming

Extension can play a valuable role by bringing together those who are pioneering innovative practices. We planned, built, and evaluated an Extension symposium on dryland organic agriculture. Post-symposium evaluations indicated that this process disseminated regionally relevant information; fostered networks among producers, researchers, and the organic processing and feed industries; enhanced trust among stakeholders; and increased interest in expanding organic production. Ninety-five percent of respondents indicated that they established new business relationships within 6 months of the symposium. A unique aspect of our project was the enhancement of social capital between geographically separated rural localities

Bacteria and Competing Herbivores Weaken Top–Down and Bottom–Up Aphid Suppression

Herbivore suppression is mediated by both plant defenses and predators. In turn, plant defenses are impacted by soil fertility and interactions with soil bacteria. Measuring the relative importance of nutritional and microbial drivers of herbivore resistance has proven problematic, in part because it is difficult to manipulate soil-bacterial community composition. Here, we exploit variation in soil fertility and microbial biodiversity across 20 farms to untangle suppression of aphids (Brevicoryne brassicae) through bottom–up and top–down channels. We planted Brassica oleracea plants in soil from each farm, manipulated single and dual infestations of aphids alone or with caterpillars (Pieris rapae), and exposed aphids to parasitoid wasps (Diaeretiella rapae) in the open field. We then used multi-model inference to identify the strongest soil-based predictors of herbivore growth and parasitism. We found that densities of Bacillus spp., a genus known to include plant-growth-promoting rhizobacteria, negatively correlated with aphid suppression by specialist parasitoids. Aphid parasitism also was disrupted on plants that had caterpillar damage, compared to plants attacked only by aphids. Relative abundance of Pseudomonas spp. bacteria correlated with higher aphid growth, although this appeared to be a direct effect, as aphid parasitism was not associated with this group of bacteria. Non-pathogenic soil bacteria are often shown to deliver benefits to plants, improving plant nutrition and the deployment of anti-herbivore defenses. However, our results suggest that these plant growth-promoting bacteria may also indirectly weaken top–down aphid suppression by parasitoids and directly improve aphid performance. Against a background of varying soil fertility, microbial biodiversity, competing herbivores, and natural enemies, we found that effects of non-pathogenic soil microbes on aphid growth outweighed those of nutritional factors. Therefore, predictions about the strength of plant defenses along resource gradients must be expanded to include microbial associates

Access to AgriculturalInputs, Technology and Information, Communicating with Farmers,and the Role of Women in Agriculture: Perceptions of Iraqi Extension Agents

The goal of this study was to gain a more comprehensive understanding ofaccess to inputs,technology and information available toIraqi extension agents,and to ascertain current farmercommunication strategies and gender roles within the diverse Iraq agricultural extension system.The conflicts, government policies, and economic sanctions that have enveloped Iraq over thelast several decades have significantly impacted access to agricultural resources. Iraqi extensionpersonnel participating inthe Iraq AgriculturalExtension Revitalization (IAER)programprovided their perspective on the availability of agricultural supplies, technology and relatedinformation. About two-thirds of the extension agents indicated that the flow and availability ofagricultural supplies has become less restricted and generally felt that there was greater accessto basic agricultural information compared to the previous decade. Despite perceivingnoticeable improvement overall in access to agricultural supplies and technology, over 83% ofthe program attendees agreed that access to agricultural inputs was currently insufficient tosuccessfully promote productive agricultural practices. An overwhelming preference for face-to-face communication by both farmers and extension personnel also limits the extent to whichagricultural information can be disseminated. In addition, several regional and gender-baseddifferences emerged.Notably, it appears that farmers donot approachfemaleextensionpersonnel equally, wherein better educated farmers are more likely to interact with femaleextensionagents.We suggest that an approach based on a horizontal exchange of knowledgebetween extension personnel and local farmers, coupled with a better integration of womenextension personnel, will help a revitalized Iraqi extension system achieve greater agriculturalsustainabilit

Effect of Arbuscular Mycorrhizal Fungi, Selenium and Biochar on Photosynthetic Pigments and Antioxidant Enzyme Activity Under Arsenic Stress in Mung Bean (Vigna radiata)

Environmental perturbations alter biochemical compounds in food crops. Arsenic (As), a toxic metalloid, is known to affect the cultivation of food crops in many regions of the world; however, the changes in chlorophyll, catalase (CAT), and proline in response to As stress and the role of stress relief substances remain largely unknown in mung bean (Vigna radiate L.). In this study, biochar (BC), arbuscular mycorrhizal fungi (AMF), and selenium (Se) were applied to soils as stress relief substances (under 30 mg kg-1 As stress), and the effects of BC, AMF, and Se on chlorophyll a, chlorophyll b, total chlorophyll, CAT activity, and proline content were studied in different mung bean genotypes. Under As stress, the chlorophyll a, chlorophyll b, and total chlorophyll contents in BARI mung 3, BARI mung 5, and BARI mung 8 were found statistically similar. Meanwhile, CAT activity increased in comparison to the control due to the application of BC, AMF, and Se in mung bean crops. However, proline was found significantly lower in AMF, BC, and Se-treated mung bean. This indicates that oxidative stress was potentially minimized in As-stressed mung bean crops due to the application of these stress relief substances. Notably, AMF was relatively effective against As stress in comparison to BC and Se. It is concluded that BC, AMF, and Se are all highly effective in enhancing antioxidant defenses as well as the nutritional quality of mung bean crops under As stress

On-farm composting of large animal mortalities

Composting can be a safe and effective method for disposing of on-farm mortalities when the correct procedures are followed and the system is managed well. This bulletin provides the necessary information for large animal producers in Washington State to start and maintain a safe and effective on-farm mortality composting system

One Plus One Equals Three: The Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition

Corn grown under annual corn-soybean crop rotation has greater accumulation of certain mineral nutrients and higher yields than corn grown in monoculture. This study was conducted to determine if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-soybean- wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high input (fertilizer application for 8.15 Mg ha-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha-1 yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel plow/spring disk and cultivation operations)] on soil fertility (pH, organic matter, NO3-N, P, K, and total N) and on corn shoot dry weight, mineral nutrient (N, P, Ca, Mg) concentration and accumulation at tassel stage of development were investigated at Brookings, SD. Soil samples taken at the V6 stage of corn development indicated that crop rotation treatments reduced soil pH, increased soil NO3-N level, and decreased soil P level when compared to corn monoculture. Shoots of plants grown under either 2-yr rotation intermediate input or 4-yr rotation no input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. These results demonstrate a beneficial effect of crop rotation upon soil fertility and corn mineral nutrition. The results of this experiment are discussed in terms of nutrient synergisms whereby nutrient absorption proceeds at a faster rate than dry weight accumulation

Use of Phospholipid Fatty Acids and Carbon Source Utilization Patterns To Track Microbial Community Succession in Developing Compost

Carbon source utilization and phospholipid fatty acid analyses were used to track the rapidly changing microbial community in composting dairy waste. Microbial abilities to utilize common plant sugars increased during composting. Community phospholipid profiles changed significantly over time. Phospholipids suggested the presence of more thermophiles and fewer bacteria with continued compost development

PLANT UPTAKE OF SOLUBLE ORGANIC MOLECULES AS N SOURCE

Plants take up nitrogen principally in the form of nitrate and ammonium; however, evidence is growing that they can also utilize organic nitrogen in the form of amino acids and soluble proteins. We are conducting research to determine whether wheat grown in soil fertilized with organic N utilizes more organic N directly than wheat grown with inorganic N. We are also testing for differences in uptake of amino acids between pre 1930s varieties and modern varieties of wheat to determine whether this trait has been selected for or against by breeding under high inorganic N input. Preliminary results show both wheat varieties Arco and Madsen take up 14C labeled glycine under sterile conditions. Further experiments to determine the role of microbial competition are underway. Selecting varieties well adapted to competing for organic N could be an important means of maximizing productivity in organic and low input agricultural systems as plants gain more effective access to a wider pool of available nutrients in any given time