Comparison of Raw Dairy Manure Slurry and Anaerobically Digested Slurry as N Sources for Grass Forage Production

Table 4

Application rate of fertilizer source at each application period, and seasonal total N and P inputs, 2009–2011.

Application	1	2	3	4	5	1	2	3	4	5	Seasonal total
	Total N kg ha^−1					NH4^+–N kg ha^−1					Total N kg ha^−1	NH4^+–N kg ha^−1	Total P kg ha^−1
	2009
Control	111^a	0	0	143^b	0	51	0	0	83^b	0	254	135	0
Urea	111^a	112	112	143^b	112	51	112	112	83^b	112	590	471	0
Raw	111^a	121	168	143^b	47	51	64	78	83^b	23	590	300	130
Digested	111^a	176	115	143^b	81	51	114	93	83^b	47	626	389	121
	2010
Control	0	0	0	0	0	0	0	0	0	0	0	0	0
Urea	112	112	112	112	0	112	112	112	112	0	448	448	0
Raw	92	112	113	99	84	53	24	58	53	53	500	240	92
Digested	86	121	63	67	129	55	40	35	40	98	466	268	54
	2011
Control	0	0	0	0	0	0	0	0	0	0	0	0	0
Urea	0	112	112	112	0	0	112	112	112	0	336	336	0
Raw	0	52	60	84	63	0	34	24	29	47	258	135	51
Digested	0	33	136	69	70	0	23	52	33	27	308	134	26

^aEarly season slurry application by grower, prior to plot establishment.
^bApplication 4 in 2009 was an unintended application from the grower to all plots. Urea fertilizer considered equal to NH₄⁺ in plant availability.