Spreading Solid Manure

Factors Affecting Application Width of spread Width of spread Speed of the tractor Speed of the tractor Density of the manure/compost Density of the manure/compost Changes across the width of spread Changes across the width of spread

Calculate How Much to Spread Base the amount of manure on the amount of nitrogen the crop needs Base the amount of manure on the amount of nitrogen the crop needs –By knowing the field size you can calculate the weight of manure to be applied

Good Distribution Important Manure or compost should be spread uniformly Manure or compost should be spread uniformly –To get the best crop yields –To maintain the best water quality Non-uniform application Non-uniform application –Uneven crop growth and production –Poor yields

Soil Compaction With heavy machinery we worry about soil compaction in the U.S. With loads under 4500 kg/axle compaction should not be a problem

Spreaders Different types of solid manure spreaders Different types of solid manure spreaders –Rear delivery spreaders –Side delivery spreaders

Rear Delivery Spreader

The Load Moves Back as the Manure is Distributed onto the Ground

Rear Delivery Spreader Note the narrow distribution pattern

Side Delivery Spreader Wider distribution pattern

ISU Research ISU research looked at distribution across the machine width and along the direction of travel ISU research looked at distribution across the machine width and along the direction of travel

Laid Out Plastic Trays

Drive Across the Trays

Weigh the Amount on Each Tray

Swath = 25 ft Rate = 20,820 lb/ac CV = 82 Fall ‘01

Swath = 12.5 ft Rate = 35,700 lb/ac CV = 40 Fall ‘01

Swath Width The swath width…distance between each pass with the spreader…was ½ the total width of throw. The overlap evens out the decreasing application rate near the edges. The swath width…distance between each pass with the spreader…was ½ the total width of throw. The overlap evens out the decreasing application rate near the edges. Pass #

Application Rate Notice the application rate of the manure. - By making such close swath widths (3.8m wide) the application rate is very high…35,700 lb/ac (40,067 kg/ha) of manure - Nutrients will be over applied and wasted - Water quality will be threatened by the excess nutrients

Side Delivery Spreader

Swath = 75 ft Rate = 2430 lb/ac CV = 39 Fall ‘01

Swath = 37.5 ft Rate = 4260 lb/ac CV = 41 Fall ‘01

Application Rate Notice the application rate of the manure. Notice the application rate of the manure. - By making wide swath widths (11.5m wide) the application rate is still low…4260 lb/ac (4770 kg/ha) of manure, even with the overlaps - Nutrients can be applied heavier by driving slower to achieve the desired application rate - Water quality will not be threatened by the excess nutrients

Hand Distributed Manure You can control the distribution very closely when distributing manure by hand…both the uniformity and the amount

Manure Uniformity Uneven distribution is a problem, as we have seen, even when manure has uniform nutrient content Uneven distribution is a problem, as we have seen, even when manure has uniform nutrient content If the manure is not uniform, getting good nutrient distribution is nearly impossible If the manure is not uniform, getting good nutrient distribution is nearly impossible Composting helps make the manure more uniform Composting helps make the manure more uniform

Conclusions from ISU Study 1. Distribution across-the-swath is more variable than in the travel direction. 2. For a rear-delivery, beater-type spreader, heaviest application is between or near the wheelbase.

Conclusions (Cont.) 3. Uniformity increases when application swath is adjusted so that overlap occurs at ½ the peak application rate. 4. Load position did not affect distribution uniformity, but faster apron speed improved uniformity.

Example of Overlap 50% overlap Resulting uniform distribution

Conclusions (Cont.) 5. Application rate of a side-delivery spreader is lower than a rear-delivery, beater-type spreader. 6. A deflector may assist in directing throw on a side-delivery spreader.