Studies were initiated near Zhoda, MB, to determine the impact of the timing and rate of hog manure
applied to forage grown on coarse textured soils with high water tables. Precipitation and soil
groundwater data were also collected. In Experiment 1, manure treatments equivalent to 0, 60, 90, 120 lb
N ac-1 were applied commencing in the summer of 2002 in summer and fall after forage harvesting; a
treatment consisting of a split application of manure equivalent to 120 lb N ac-1 was also applied (60 lb
ac-1 each in summer and fall). Four replicates were arranged in a completely randomized design. In
Experiment 2, manure was applied at rates equivalent to 0, 100, 200, 300, and 400 lb N ac-1 in spring
2004 in three replicates in a strip plot design. Besides forage yield and quality, the distribution of nitrate-
N and phosphorous in the soil profile was also monitored in both experiments. Forages responded strongly to manure application with respect to nutrient uptake, nutrient content, and
dry matter yield. In Experiment 1, dry matter yields increased considerably as manure application rate
increased, as did nutrient uptake. was a trend in most instances of increasing nutrient content with
increasing manure application rate. Fall-applied manure appeared to produce higher forage yields,
possibly as a result of greater nutrient losses in summer-applied treatments as well as the lack of nutrient
response when dry conditions prevailed during the summer period. Split N application was no more
effective at increasing forage productivity than the 120N treatment when considering productivity over a
production cycle (i.e. fall and summer harvest). Tming of nutrient availability is a key consideration in
attempting to maximize forage productivity. In Experiment 2, for example, it was clear that nutrient
availability was delayed somewhat relative to application date, as indicated by a delay in the
accumulation of nitrate-N in the upper soil profile. Given the lack of leaching observed in Experiment 1
(up to target N rate of 120 lb ac-1), increasing manure application rates may be feasible relative to current
recommendations. Splitting manure application rates may also provide another means of increasing
manure application rates without causing adverse effects to the environment.