Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2007
Publication Date: 6/29/2007
Citation: Wu, Z., Powell, J.M. 2007. Dairy Manure Type, Application Rate and Frequency Impact Plants and Soils. Soil Science Society of America Journal. 71(4):1306-1313. Interpretive Summary: An increased emphasis on whole-farm nutrient management planning requires new information on possible impacts of dairy cow diets on manure nutrients and subsequent crop production. Manure from lactating dairy cows fed three diets differing in crude protein (CP) content were applied to a silt loam and a sandy loam soil at two application rates (agronomic rate and twice agronomic rate), and three application frequencies (once, twice or thrice) in a greenhouse trial. Soil type had the greatest impact on oat, sudangrass and soil response variables, followed by manure application rate and frequency. Plant uptake of manure nitrogen was highest in pots amended with manure from the low CP diet applied as a single application. We will continue to evaluate impacts of dairy cow diets on manure, plants and soil so dairy producers and their advisors will have this information for use in whole-farm nutrient management planning.
Technical Abstract: In many regions of the US, the rate and frequency of manure application to cropland are regulated based on the nitrogen (N) requirements of the subsequent crop. While information is available on impacts of dairy diets on manure N composition, its mineralization in soil and crop N uptake after single manure applications, no information is available on these impacts when manure is applied at different rates and frequencies. Manure from lactating dairy cows (Bos taurus) fed three diets differing in crude protein (CP) content were applied to in a Plano silt loam soil (Fine-silty, mixed, superactive, mesic, Typic Argiudolls) and Rosholt sandy loam soil (Coarse-loamy, mixed, superactive, frigid, Haplic Glossudalfs), at two application rate (R1, 225 kg; or R2, 450 kg total N ha-1), and three application frequencies (F1, once; F1+F2, twice; or F1+F2+F3, thrice). Oat (Avena sativa L.), sorghum (Sorghum bicolor L. Moench) and sorghum ratoon were grown in succession for a total of 170 d. Response variables included shoot dry matter (DM), N uptake and nitrate concentrations, root organic matter (OM) and N, and soil pH and inorganic N (IN). General results showed that soil type had the greatest impact on plant and soil response variables, followed by manure application rate and frequency. Plant uptake of applied manure N was highest in pots amended with manure from the low CP diet applied as a single application (F1). Plant and soil responses to manure types were less pronounced than expected.