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<OL> <LI> Determine the levels of selected phytochemicals in tomato and pac choi grown with organic and conventional fertilizers at low and high N application rates.<LI> Assess the activation of key genes involved in the biosynthesis of phytochemicals in tomato and pac choi as a potential technique for rapid evaluation of crop response to organic fertility treatments. <LI> Measure soil fertility and quality and plant nutrient status in relation to tomato and pac choi production at high and low rates of N-fertilization in open field and high tunnel production systems. <LI> Use field and greenhouse studies to measure the effects of organic N-fertilization and high tunnel production environments on insect and disease pressure in tomato and pac choi. <LI>Determine the relationship between phytochemical content (in response to organic N-fertilization) and disease and insect pest reaction. <LI>Develop fact sheets, websites, workshops, and other outreach information and evaluate impact using pre- and post-tests. Integrate the outreach information into new courses at KSU and develop formats available for distance-education.
Non-Technical Summary: The goal of this multidisciplinary project is to improve our understanding of the influence of organic fertilizer sources on crop health, including pest and disease resistance, yield, and quality of vegetable crops. Specifically, we will compare low and high rates of selected organic fertilizer sources and contrast them to equivalent rates of conventional fertilizers in replicated, long-term field and high tunnel (unheated greenhouse) plots. The effect of these four contrasting systems will be measured on plant and soil nutrient status and soil quality attributes. Insect and disease presence and abundance on plants will be assessed. We will also evaluate whether there is an influence on phytonutrient and phytochemical levels (?-carotene, folic acid, vitamin C, vitamin E, individual and total phenolics, and antioxidant levels) and whether these, in turn, affect pest and disease incidence. Crops evaluated will include tomato and pac choi. Tomato is economically important, and pac choi, an important Asian vegetable, has proven to be a valuable model crop in our preliminary studies, due to its responsiveness to fertility, susceptibility to insect attack, and phytochemical response. This three-year effort will emphasize regionally available organic fertility options in experiment station and farm-based studies to produce results with specific regional application, but with broader relevance to global organic production. <P> Approach: Overview of field site, Replicated trials will be conducted at the KSU Research and Extension Center, Olathe. At this site, 3 organic high tunnels (20ft x 32ft Stuppy Polar Cold Frames, with single layer poly and 5ft rollup sides) and 3 conventional tunnels were established in a paired replicated arrangement in 2002, to allow statistically valid comparisons between organic and conventional systems. Adjacent replicated organic and conventional field plots provide additional environments and permit comparisons between high tunnel and open field conditions. Experimental approach. Soil fertility treatments chosen during the course of trials conducted under this project will be determined by the project team and advisory group, and will be selected based on N availability from mineralization study results, total N content, local availability, cost and other factors, so that the organic fertility treatments represent actual on-farm practices typical of the Great Plains. Soil fertility treatments in the form of composts will be chosen that meet requirements of the National Organics Standards Board for soil fertility and crop nutrient management. Fertility applications will be consistent across all treatment replications and carefully quantified. High fertility levels for organic treatments will be based on soil analyses, and will start from the reference point of our current practice, which is to apply compost at double the conventional N fertilizer requirement for conventionally grown vegetable crops in Kansas. Low fertility levels will be established by applying N at sub optimal rates in organic and conventional plots, with rates to be determined based on soil tests, but aiming to supply one half the required N for the crop. High N plots will likely receive split applications, with shallow pre-plant incorporation of compost followed by fertigation with water soluble fertilizer (e.g., fish emulsion). Low N plots would receive only pre-plant fertility treatments. Inorganic fertilizer salts that are immediately soluble will be applied to the inorganic fertilizer plots. Application rates of other nutrients (P, K, etc.) will be matched between conventional and organic treatments to the extent possible, but the intention of our treatment selection is to represent actual on farm practices. Therefore, effects of any differences in application rates of nutrients besides N, such as micronutrients that are applied via fish emulsion in the organic treatment but not in the inorganic treatment, will be assessed with the plant tissue and soil analyses. Differences between conventional and organic treatments can be correlated to yield and other responses with multivariate statistical analyses. The influences of N-sources at low and high rates on crop phytochemistry, and on disease and pest incidence and reaction will be examined on selected vegetable crops, particularly tomato and pac choi.