Frequency of manure application in organic versus annual application of synthetic fertilizer in conventional vegetable production

Authors: Russo, Vincent; TAYLOR, MERRITT - Oklahoma State Experiment Station

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2010
Publication Date: 11/5/2010
Citation: Russo, V.M., Taylor, M.J. 2010. Frequency of manure application in organic versus annual application of synthetic fertilizer in conventional vegetable production. HortScience. 45(11):1673-1680.

Interpretive Summary: Conventional fertilizers are quickly soluble and readily available to the plant. Manure as an organic fertilizer takes time to break down and is used to change the soil condition. As a result manure may not be completely used in a single year and carry over. It is not clear if it is necessary to apply manure every year to the soil to maintain yields and profit levels. Manure was applied either annually, or biannually, to bell pepper, cv. Jupiter, cucumber, cv. Earli Pik, and sweet corn, cv. Incredible (se endosperm genotype), and results were compared to production of these crops using synthetic fertilizer applied annually. Yields and nutrient contents of the soil and edible plant parts were determined over a four-year period. Economic comparison was done. Application of manure on an annual basis produce higher yields in bell pepper and sweet corn than when manure was applied on a biennial basis. Profit was greater for all crops when manure was used and greater for bell pepper and sweet corn when it was applied annually. It appears that it is necessary to apply manure annually for most vegetable crops.

Technical Abstract: Transporting manure is an input cost that can affect profit. Manure was applied either annually, or biannually, to bell pepper (Capsicum annuum L.), cv. Jupiter, cucumber (Cucumis sativus L.), cv. Earli Pik, and sweet corn (Zea mays var. rugosa Bonaf.), cv. Incredible (se endosperm genotype), grown using organic methods and materials and results were compared to production of these crops using conventional methods and with synthetic fertilizer applied annually. Conventional and organically maintained portions of the field were separated by a 25 m buffer zone planted with the same sweet corn cultivar which was provided manure as fertilizer. Nutrient contents of soil and edible portions were determined, as were yields. Economic analyses comparing yields, prices, and costs of production of the crops was conducted. There were yield responses due to year. Bell pepper yield was little affected by type of fertilizer application. Cucumber and sweet corn benefitted from use of manure over conventional fertilizer. There was no pattern of alternating increased or decreased nutrient content in edible portions or in the soil, due to type of fertilizer used, or to annual or biennial application of manure. Economic analyses indicated that treatment with manure produced higher returns than treatment with conventional fertilizer. Treatment annually with manure produced higher returns in bell pepper and sweet corn than did treatment with manure in alternate years, but the opposite was true for cucumber. Annual application of manure appears to be necessary for most vegetable crops.