Are there research reports available on crop response to hydrolyzed fish fertilizers, especially on pivot-irrigated rotational pastures?
K.B.WyomingAnswer: Searching the Internet, the AGRICOLA bibliographical database, and the CAB Abstracts bibliographical database, you’ll see that very little has been published beyond a few horticultural studies on hydrolyzed fish, fish emulsion, and fish hydrolysate.The most interesting and relevant research report is probably “Efficient Use of Organic Nitrogen Sources in Green Pepper,” Organic Farming Research Foundation Research Report 98-04, published by Mark Gaskell, Farm Advisor, UC Cooperative Extension, Santa Maria, California. It provides a comparison of compost, pelletized chicken manure, fish meal, liquid fish, bloodmeal + feathermeal, feather meal, and seabird guano, and their effect on soil nitrate nitrogen and bell pepper yields. Further, it compares cost per pound of nitrogen supplied from each product, and also the “additional gross return on peppers per dollar cost of fertilizer.”Ther were no reports directly addressing the use of liquid fish fertilizers in agronomic crop and forage production.Here are a few options to consider.In the early phase of transition from chemical fertilizer-based farming to organic farming, it can be helpful to amend soils with compost at a high rate of application per acre; e.g., 5 to 10 tons per acre. Thereafter, a maintenance rate of compost at 3 to 5 tons per acre may be sufficient. These guidelines are more typical for cropland agriculture.With rotational grazing, it can still be very helpful to make an initial application of compost to supply an organic soil amendment and assist with forage establishment. However, once rotational grazing is underway the system itself is capable of maintaining most or all of its needed nitrogen fertility through nutrient cycling, the use of legumes in the forage mix, and the deposition of urine and manure combined with stomping and mixing from hoof action. A soil test can provide guidance on any additional minerals that will need to be replenished through the use of rock phosphate fertilizer and so forth.If you can obtain compost at a reasonable cost per acre, you will get greater benefit from a compost application than from liquid fish fertilizer. Another alternative to liquid fish fertilizer is compost tea.Compost tea has three principle components: soluble nutrients, bioactive substances that promote plant growth, and beneficial microorganisms. Compost teas that are aerated and brewed with compost tea additives (e.g., molasses, kelp, yucca extract) are, essentially, a bioaugmentative input to enhance the beneficial microbial communities that inhabit the rhizosphere (soil root zone) and phyllosphere (plant leaf zone). In addition, compost teas can be made for less than fish fertilizer costs.Finally, should you wish to explore the use of fish fertilizers as a fertigation input, use the manufacturer’s directions for application rates per acre.ResourcesEfficient Use of Organic Nitrogen Sources in Green PepperOFRF Research Report 98-04Mark Gaskell, Farm Advisor, UC Cooperative Extension, Santa Maria, California www.ofrf.org/publications/Grant%20reports/98.04.02.Gaskell.Spr98.IB9.PDFMarine By-Products as FertilizersDavid ChaneyComponents Newsletter, UC-SAREPWinter 1991 (v2n1)www.sarep.ucdavis.edu/newsltr/components/v2n1/sa-10.htmSeafood Waste Management BibliographyKen Hilderbrand, Oregon State UniversityHTMLhttp://seagrant.oregonstate.edu/sgpubs/onlinepubs/i01002.htmlPDFhttp://seagrant.oregonstate.edu/sgpubs/onlinepubs/i01002.pdf