Table 2.

Moderator factors used to group the data and number of observations

Factor	Number of observations
Vegetation
Ryegrass	105
Other	41
Missing	7
Clover
Yes	83
No	65
Missing	5
Diet
Forage	81
Supplemented	34
Missing	38
Urine type
Dairy cow urine	92
Non‐dairy cow urinea	32
Sheep urine	29
Soil texture
Clay loam	32
Sandy loam	49
Silty loam	65
Other	7
Soil type
Freely draining	74
Moderately draining	12
Poorly draining	53
Unknown	14
Time of applicationb
Spring	43
Summer	28
Autumn	54
Winter	19
Missing/other	9
Year
2000–2016	153

^aIncludes unspecified cows.

^bIf two seasons given, then first is used, other seasons (wet, dry, cool) excluded as they have few observations.