first rainfall simulation event, a period of approximately 48 hours.
On the same day that slurry was applied, the sub-plots were hydrologically isolated from overland and shallow sub-surface flow by inserting stainless steel surrounds into the soil along the sides and across the up-slope end of each plot to a depth of 0.05 m.
Rainfall simulations were carried out using the same methodology as described in a number of similar studies: Brennan et al . (2011) , O’Rourke et al . (2012) , McConnell et al . (2013 a , b ), Doody et al
V. Nagarajappa, S.N. Battula, S. Arora and L.N. Naik
10–12 h and then churned into butter using a domestic mixer (National, Bengaluru, India). The butter was washed with cold water to remove excess buttermilk and was heated with continuous stirring in a stainless steel container. The heating was adjusted so that the temperature rose very slowly and did not exceed 100°C. Finally, the clarified fat was filtered using Whatman Grade No. 4 filter paper to obtain butteroil with a moisture content of <0.3%.
Preparation of oil-in-water (o/w) emulsion
DATEM were used as an emulsifier and butteroil was used as a source
W. Burchill, G.J. Lanigan, P.J. Forrestal, F. Reville, T. Misselbrook and K.G. Richards
used to measure NH 3 volatilisation. Each wind tunnel unit consisted of (i) a canopy (0.5 m × 2 m) made of polycarbonate, (ii) a galvanised sheet steel duct and (iii) a control box. The wind tunnel canopy was placed over each lysimeter immediately after urea application and it stayed in place until the end of the experiment. Wind speed through the wind tunnels was set at 1 m/s (air flow rate of 0.229 m 3 /s), which was chosen to mimic atmospheric wind speed above the soil surface. Air entering and leaving the wind tunnel canopy was sampled and pumped through two