EXECUTIVE SUMMARY Continuous application of manure P above crop removal results in a buildup of soil phosphorus (P), which increases the risk of P runoff loss from agricultural landOrganic forms of phosphorus, P associated with organic matter P t Total phosphorus, equal to inorganic plus inorganic P Water-P i Inorganic P in water extractable fraction in manure Water-P o Organic P in water extractable fraction in manure Water-P t Total P in water extractable fraction in manure NaHCO 3 -P iInorganic P in sodium bicarbonate extractable fraction in manure NaHCO 3 -P o Organic P in sodium bicarbonate extractable fraction in manure NaHCO 3 -P t Total P in sodium bicarbonate extractable fraction in manure NaOH-P i Inorganic P in sodium hydroxide extractable fraction in manure NaOH-P o Organic P in sodium hydroxide extractable fraction in manure NaOH-P t Total P in sodium hydroxide extractable fraction in manure HCl-P i Inorganic P in hydrochloric acid extractable fraction in manure HCl-P o Organic P in hydrochloric acid extractable fraction in manure HCl-P t Total P in hydrochloric acid extractable fraction in manure Labile-P i Inorganic P extracted by water + inorganic P extracted by NaHCO 3 Labile-P t Total P extracted by water + total P extracted by NaHCO 3 MAP Monoammonium phosphate synthetic fertilizer (11-52- Alberta Agriculture and Rural Development for the loaned rainfall simulator equipment.

No abstract

Ige, D. V., Sayem, S. M. and Akinremi, O. O. 2015. Nitrogen mineralization in beef-and pig-manure-amended soils measured using anion resin method. Can. J. Soil Sci. 95: 305Á319. A major challenge facing the widespread use of manure is the uncertainty about its fertilizer equivalence. This study was carried out to determine the fertilizer equivalence of locally available manures in two soils in Manitoba. A randomized complete block design was adopted with six treatments [nitrogen fertilizer, a liquid swine manure (LSM), three solid beef manures (SBM) and a control] and four replicates. Each treatment was applied to a cylindrical soil column installed at the site at the rate of 100 kg ha(1 of ''available N'', and leached NO 3 -N was captured by resin bags at the bottom of the cylinder. The soils and resin bags removed from the cylinders were sampled at 0, 1, 2, 4, 6, 8, 10, 14, and 18 wk following treatment application. Ammonium nitrogen in the amendments was nitrified within the first 2 to 3 wk with significant build-up of NO 3 -N in the soil above the control (PB0.05). The greatest available N was in the fertilizer treatment, followed by the LSM and the smallest was in the SBM. The available N in the three SBM was statistically similar (P0.05). Approximately 50% of the inorganic N in LSM was available during the growing season, while 68 to 100% of SBM inorganic N was available. Between 4 and 25% of the organic N in the three SBM was mineralized during the growing season. High soil moisture hindered N mineralization and enhanced N loss in the clay soil. LSM has the greatest fertilizer equivalence, with a mean of 65 to 68%, of the four manure types used. The fertilizer equivalence of the three SBM ranged between 42 and 59% and was influenced by the manure C:N ratio and the soil environmental conditions. Our study suggests the need to revise the assumptions regarding manure N availability by considering soil environmental factors in the estimation of available N. L'azote ammoniacal des amendements se nitrifie au cours des deux ou trois premie`res semaines et on observe une importante accumulation de N-NO 3 dans le sol au-dessus du traitement te´moin (P B0,05). La plus grande quantite´de N disponible a e´te´releve´e avec l'usage d'engrais, puis de lisier de porc, la plus faible de´coulant de l'application du fumier de bovins. La quantite´de N disponible dans les trois types de fumier de bovins e´tait statistiquement similaire (P 0,05). Environ 50 % du N inorganique pre´sent dans le lisier de porc peuvent eˆtre utilise´s durant la pe´riode ve´ge´tative, contre 68 a`100 % de celui pre´sent dans le fumier de bovins. Quatre a`25 % du N organique pre´sent dans les trois fumiers de bovins sont mine´ralise´s pendant la pe´riode de croissance. Une forte teneur en eau dans le sol nuit a`la mine´ralisation du N et favorise la perte de N dans le sol argileux. Le lisier de porc se rapproche le plus des engrais, avec une e´quivalence moyenne de 65 a`68 % pour les quatre types de fumier teste´s. L'e´quivalence des trois types de ...

Olatuyi, S. O., Akinremi, O. O., Flaten, D. N. and Lobb, D. A. 2012. Solute transport in a hummocky landscape: I. Two-dimensional redistribution of bromide. Can. J. Soil Sci. 92: 609–629. Bromide has been widely used in field studies to estimate nitrate leaching in agricultural soils. This study examined the impacts of crop response to nitrogen fertilization on the vertical and lateral redistribution of bromide in the fall and spring seasons in a hummocky landscape. The study was carried out near Brandon, Manitoba, in 2007 and 2008, using two separate plots (Site-2007 and Site-2008). The plots were delineated into three landscape positions as upper (UPP), middle (MID) and lower (LOW) slope. A microplot at each landscape position received 15N labelled fertilizer (KNO3) at the rates of 0, 90 and 135 kg N ha−1, and KBr at the rate of 200 kg Br− ha−1. Site-2007 was seeded to canola while Site-2008 was seeded to winter wheat. Soil samples were taken within the microplot to a depth of 120 cm for vertical distribution, and up to 200 cm away from the microplot for lateral distribution of Br− in the top 20 cm depth. The downward movement of Br− in the soil was reduced under N fertilization. This resulted in the accumulation of Br− in fertilized plots, and a greater lateral movement of Br− in fertilized compared with unfertilized plots. The greatest vertical and lateral movement of Br− occurred at the LOW slope position. In the fall season following Br− application, 55 and 15% of the Br− applied were recovered in the vertical and lateral components of the landscape, respectively. Estimated loss of Br− due to vertical and lateral movement was 47% in the unfertilized treatment and 36% with N fertilization. The order of Br− loss in the two dimensions was: LOW (48%)>MID (40%)>UPP (37%). The study shows that crop response to N fertilization reduced the vertical movement of solute, thereby providing an experimental support for the “Campbell hypothesis” which states that N fertilization and proper rate of N application reduces nitrate leaching.

Woyengo, T. A., Akinremi, O. O., Rossnagel, B. G. and Nyachoti, C. M. 2012. Performance and total tract nutrient digestibility of growing pigs fed hulless low phytate barley. Can. J. Anim. Sci. 92: 505–511. An experiment was conducted to determine the performance and nutrient digestibility of growing pigs fed hulless low phytate (HLP) barley without or with phytase for 28 d. Twenty-four growing pigs (average initial body weight=25.3 kg) were fed three diets in a completely randomised design. The diets included a regular-hulled barley-based diet, and a HLP barley-based diet without or with phytase at 500 phytase units kg−1. Pigs fed the HLP barley-based diet without phytase had greater (P<0.05) average daily gain (0.911 vs. 0.717 kg), and apparent total tract digestibility of dry matter, energy, P, Mg, and Na were higher (P<0.05) than the regular barley-based diet. Supplementation of phytase to the HLP barley-based diet resulted in improved (P<0.05) feed conversion efficiency (0.506 vs. 0.547 kg kg−1), and apparent total tract digestibility of N, P and K. In conclusion, pigs fed the HLP barley-based diet had higher growth performance and nutrient digestibility than those fed the regular-hulled barley-based diet, indicating that the HLP barley is a better source of nutrients for pigs than regular barley. Phytase supplementation to the HLP barley-based diet can result in a further increase in nutrient utilisation by pigs.