Date of Award
Master of Science
Antonio P. Mallarino
Characterizing beef cattle (Bos taurus) manure P and its crop availability is essential to improve the utilization of this resource. The objectives of this study were to survey beef cattle manure in Iowa, analyze manure for P and other chemical properties, and determine the crop-availability of selected sources by soil testing. The survey samples (107) were classified into five categories according to animal and manure management: with bedding (BEDDED), open concrete floor (CONCRETE), dirt floor (DIRT), no feeding of corn (Zea mays L.) co-products (NoCCP), and slurry from deep pits (PIT). Manure total P (TP) and proportion of water-soluble P (MWSP) were higher for BEDDED, CONCRETE, and PIT [10, 11, 15 g TP kg-1 - dry matter (DM) basis - and 59, 57, and 55% of MWSP, respectively] than for DIRT and NoCCP. Representative samples from each group were selected for P fractionation analysis, and a P source-soil 23-wk incubation study that also included di-ammonium phosphate (DAP) and a control. All P sources were applied at 87 kg TP ha-1. Soils were Adair (Aquertic Argiudolls), Harps (Typic Calciaquolls), and Nicollet (Aquic Hapludolls). There were not significant or small and inconsistent changes of Bray-1 (BP), Mehlich-3 (M3P), Olsen (OP), and water-extractable (WEP) P levels over the incubation period between all sources and soils. On average, manure P effectiveness relative to DAP was greater for M3P and OP (79 and 80%) than for BP and WEP (77 and 74%); and 73, 84, and 76% with Adair, Harps, and Nicollet soils, respectively. On average across all soil P test methods, soils, and sources manure P efficiency relative to DAP differed among sources and was greatest for BEDDED and CONCRETE (84 and 85%), intermediate for PIT and DIRT (77 and 74%), and lowest for NoCCP (69%).
Dagna, Nicolas, "Application of soil test methods to study the availability of phosphorus in beef cattle manure" (2012). Graduate Theses and Dissertations. 12663.