[457][458][459][460][461][462][463][464][465][466][467]. A study was initiated in the fall of 1996 in the Black soil zone in east-central Saskatchewan (parkland region) to examine the soil and crop response to application of liquid swine manure at different rates, frequencies and methods of application. Low, medium and high rates of liquid swine manure (equivalent to approximately 100, 200 and 400 kg total N ha -1 , respectively) were applied annually and in reduced frequency applications using injection and broadcast/incorporated placement over a 4-yr period. Crops grown during this period were Argentine canola (Brassica napus L.) in 1997, hard red spring wheat (Triticum aestivum L.) in 1998, hulless barley (Hordeum vulgare L.) in 1999, and Argentine canola in 2000. Under an annual application regime, a significant elevation of pre-seeding available N in the 0-60 cm soil depth and increased grain yield and protein content with increasing application rates of liquid swine manure were observed. Under a reduced frequency application regime, elevation of pre-seeding available N, grain yield and protein content observed in the year of application declined in the second year, and were significantly diminished by the third year. Cumulative N use efficiency (NUE) was highest (50-60%) for low annual application and lowest (10-30%) for high annual application rates that were injected. Generally, injection of liquid swine manure into the soil resulted in better enhancement of pre-seeding available N, higher grain yield and protein content, and better NUE than broadcasting and incorporation. Type of opener used to inject swine manure had no significant effect on either crop response or available N. This study showed that in the Black soil zone of the parkland region of Saskatchewan, annual application of low to medium rates (100 to 200 kg total N ha -1 ) of liquid swine manure are sufficient for high grain yield and grain protein, without leaving excess nitrates in the soil. In contrast, annual application of high rates (400 kg total N ha -1 ) of liquid swine manure has no agronomic advantage over the lower rates, but may result in higher residual nitrates in the soil, increasing potential for environmental pollution.Key words: Swine manure, N availability, manure management, N use efficiency Mooleki, S. P., Schoenau, J. J., Hultgren, G., Wen, G. et Charles, J. L. 2002. Incidence du taux, de la fréquence et de la méthode d'application du purin de porc sur l'azote disponible dans le sol, sur le rendement agricole et sur l'assimilation du N dans le centre-est de la Saskatchewan. Can. J. Soil Sci. 82: 457-467. À l'automne de 1996, les auteurs ont entrepris une étude dans la zone des sols noirs du centre-est de la Saskatchewan (région des prairies-parcs) afin de vérifier la réaction du sol et des cultures à l'application de purin de porc. Le taux, la fréquence et la méthode d'application du purin variaient. Pendant quatre ans, on a appliqué au sol une faible, une moyenne ou une grande quantité de purin de porc (l'équivalent a...

. A study was initiated in 1996 in the Black Soil zone in east-central Saskatchewan to examine soil and crop response to application of feedlot cattle manure at different application rates, frequencies and incorporation timing in a sandy loam and loam soil. Three rates of feedlot cattle manure (approx. 100, 200 and 400 kg total N ha -1 ) were applied annually and under reduced frequency application regimes. Canola (Brassica napus, L.), spring wheat (Triticum aestivum, L.), hulless barley (Hordeum vulgare, L.) and canola were seeded in spring of 1997, 1998, 1999 and 2000, respectively. Pre-seeding available N (0-60 cm) increased with application rates. Annual application resulted in a linear increase in grain yield with application rates but had no effect on grain N concentration. Cumulative N use efficiency was low (7-10%) with no significant difference among treatments. Single application showed significant residual fertility benefit in the second year but not in the third year except at the high rate. Incorporation timing of feedlot cattle manure had no impact on soil or crop performance. Low availability of N in feedlot cattle manure over the short-term suggests the need for high application rates or addition of supplemental N fertilizer in order to meet crop N requirements. de 1997, 1998, 1999 et 2000, ils ont ensuite semé respectivement du canola (Brassica napus L.), du blé de printemps (Triticum aestivum L.), de l'orge nue (Hordeum vulgare L.) et du canola. La quantité de N disponible avant les semis (à une profondeur de 0 à 60 cm) augmente avec le taux d'application. Lorsque l'application est annuelle, le rendement grainier augmente de manière linéaire avec le taux d'application, mais les applications annuelles n'agissent pas sur la concentration de N dans le grain. L'assimilation cumulative de N est faible (de 7 à 10 %) et ne varie pas sensiblement d'un traitement à l'autre. Le sol garde une importante fertilité résiduelle l'année immédiate suivant l'application, mais pas l'année subséquente, sauf au taux le plus élevé. Le moment de l'incorporation n'a aucune incidence sur le rendement du sol ou de la culture. La faible assimilation à court terme du N du FB laisse croire qu'on devrait recourir à un taux d'application élevé ou ajouter un engrais azoté pour satisfaire aux exigences de la culture.

SummaryThe efficiency of nitrogen (N) derived from different manures in the years following application must be determined to optimize use of N and reduce impact on the environment. Five N efficiency parameters that were originally developed for commercial inorganic N fertilizers were selected to measure the manure N efficiency in the second year following application of liquid hog and solid cattle manure in semiarid east-central Saskatchewan, Canada. The manures were applied at two sites (Dixon and Burr) at four rates covering a range from zero to 912 kg N ha ±1 in 1997. A canola (Brassica napus L.) crop was grown in 1997 followed by a spring wheat (Triticum aestivum L.) in 1998 without fertilization. Tested by the wheat, N utilization efficiency (NUE) was similar between the two manures at either site, but it was higher at Dixon site, where the soil properties were better, than at the Burr site (P < 0.07) with cattle manure. Nitrogen physiological efficiency (NPE) was not affected by either manure source or soil. At the Burr site, N agronomic efficiency (NAE) and N recovery rate (NRR) were all higher with the hog than with the cattle manure (P < 0.08 and P < 0.07, respectively), but N harvest index (NHI) was lower with the hog than with the cattle manure (P < 0.04). The similar trends of the NAE, NRR, and NHI between the hog and cattle manure were also found at the Dixon site. However, the differences in NRR between the hog and cattle manure in the second year was rather small in contrast to the large differences in the year of application. Despite that the wheat crop utilized residual hog and cattle manure N equally efficient in producing grain yield, a higher grain N concentration and a higher NHI with the cattle than with the hog manure revealed different N supply dynamics between the two. Possibly due to the low proportion of ammonium (NH 3 )-N in the total N and the high C : N ratio in the cattle manure, mineralization of cattle manure N provided more available N in the later stage of wheat growth than did the hog manure. The N efficiency parameters were useful tools in understanding the impact of residual manure N on wheat production on the Canadian prairies.Key words: liquid hog manure / solid cattle manure / nitrogen utilization efficiency / nitrogen physiological efficiency / nitrogen agronomic efficiency / nitrogen recovery rate / nitrogen harvest index PNSS P113/5B