Effect of harrowing and watering on disappearance of dung pats in pastures

Dung pats in pastures limit grass production, and lead to grazing losses and lower eco efficiency in dairy systems. Dragging the pasture with a harrow immediately after grazing could help to break up the pats and distribute the manure more evenly. However, in the absence of rain this may result in flattened, manure-smeared grass. Harrowing drier dung pats after some days of deposition may overcome smearing of the grass. Watering the pasture immediately after harrowing can help to wash the manure off the foliage. In a field experiment we compared the following treatments to spread (artificial) dung pats: 1. Dung pat - untreated (control), 2. Harrowing immediately after deposition (day 0), 3. Harrowing + watering (10 mm) immediately after deposition (day 0), 4.Harrowing 7 days after deposition, 5. Harrowing + watering (10 mm) 7 days after deposition. The results after three weeks show that harrowing fresh dung pats (day 0), if not combined with watering, only slightly increased the dis appearance of dung (43% disappeared) compared to untreated pats (40% disappeared). Harrowing older dung pats (7 days after deposition), if not combined with watering, even resulted in lower dung decomposition than observed for the untreated pats (31% disappearance). The best result was obtained when fresh dung pats were harrowed and the pasture was watered immediately (day 0) (61% disappearance).