Effect of dairy manure type on the carbon balance of mowed grassland in Nasu, Japan: comparison between manure slurry plus synthetic fertilizer plots and farmyard manure plus synthetic fertilizer plots

Figures & data

Table 1 Manure application rates and their chemical and physical properties

Application date	Type	Wet weight (Mg ha^−1)	Dry weight (Mg ha^−1)	C input (Mg ha^−1)	N input (kg ha^−1)	C/N	Moisture content (wt%)
25 March 2008	Slurry^†	32.8	3.97	1.24	150	8.23	87.9
25 March 2008	FYM^‡	36.5	12.6	5.07	252	20.1	65.4
28 May 2008	Slurry^†	33.6	3.09	1.43	150	9.57	90.8
26 March 2009	Slurry^†	31.7	3.49	1.47	150	9.79	89.0
26 March 2009	FYM^‡	39.2	11.0	3.92	252	15.5	71.9
28 May 2009	Slurry^†	34.1	3.44	1.36	150	9.07	89.9

^†Dairy cattle slurry.

^‡Dairy cattle manure containing sawdust.

Figure 1 Temporal changes in (a) CO₂ flux, (b) temperature at a depth of 5 cm below the soil surface. Values are means ± SEM (n = 3). Vertical lines indicate fertilizer applications.

Table 2 Mineral nitrogen supplied from synthetic fertilizer, slurry, and FYM

		N supply (kg N ha^−1 year^−1) from 22 March 2008 to 21 March 2009						N supply (kg N ha^−1 year^−1) from 22 March 2009 to 21 March 2010
Plot type	Fertilizer	25 March	28 May	10 July	1 September	Slurry^† or FYM^‡	Total	26 March	28 May	13 July	1 September	Slurry^† or FYM^‡	Total
Control	Ammonium sulfate	–	–	–	–	–	0	–	–	–	–	–	0
Slurry	Slurry	(150)^§	(150)^§	–	–	120	210	(150)^§	(150)^§	–	–	120	210
	Ammonium sulfate	–	–	60	30	–		–	–	60	30	–
FYM	FYM	(252)^§	–	–	–	33	210	(252)^§	–	–	–	51	210
	Ammonium sulfate	40	47	60	30	–		29	40	60	30	–

^†Mineral N supplied from slurry was estimated to be 40% of the total content in the applied year (HPAES and HARC 2004).

^‡Mineral N supplied from FYM was estimated to be 13.4% of the total content in the applied year and 7.0% in the following year, respectively (Shiga et al. 1985; HPAES and HARC 2004).

^§Total N in the applied slurry or FYM is shown in parentheses.

Table 3 CO₂ emission from grassland, R_s and R_m

	CO2 emission
Plot	1st year (Mg C ha^−1 year^−1)	2nd year (Mg C ha^−1 year^−1)	Total (Mg C ha^−1 2-years^−1)	Treatment effect	Rs^†(Mg C ha^−1 2-years^−1)	Rm^‡ (Mg C ha^−1 2-years^−1)
Control	4.2 ± 0.6	4.0 ± 0.3	8.2 ± 0.8	a	8.2	−
Slurry	6.8 ± 0.0	6.0 ± 0.1	12.8 ± 0.1	b	8.2	4.6
FYM	5.6 ± 0.5	4.7 ± 0.9	10.3 ± 1.3	a	8.2	2.1
Interannual difference	A	A

Values are means ± SEM (n = 3). Different letters represent significant differences among treatments (P < 0.05, Scheffé's test) or years (P < 0.05, ANOVA).

^†R_s was assumed to be the cumulative CO₂ emission in the control plots.

^‡R_m was estimated by subtracting R_s from the cumulative CO₂ emissions in the slurry and FYM plots.

Figure 2 (a) Manure input for each crop and (b) manure that remained on 21 March 2010. FYM, farmyard manure; R_m, manure decomposition.

Figure 3 Dry matter yields (Scheffé’s test). FYM, farmyard manure.

Figure 4 (a) Plant residue inputs and (b) amount of plant residues remaining until the end of the study (21 March 2010). FYM, farmyard manure. R_p, decomposition of plant residue.

Figure 5 Proportion of the plant-residue mass in the litter bags remaining at various times during the study period. Values are means ± SEM (n = 5). Arrows represent the harvest times for the1st to 4th crops.

Figure 6 Carbon contents in the roots and stubble. Values are means ± SEM (n = 3). FYM, farmyard manure.

Figure 7 (a) Soil inputs and outputs of C to the soil and (b) net SOC balance. FYM, farmyard manure; R_p, decomposition of plant residues; R_m, decomposition of manure; R_s, decomposition of soil organic matter; SOC, soil organic carbon.

Hokkaido Prefectural Agricultural Experiment Stations and Hokkaido Animal Research Center (HPAES and HARC) 2004: Method for manure utilization. In Handbook of Animal Waste Management and Utilization in Hokkaido 2004, Eds. Ohara M, Takeda Y, Omura K, pp. 64–67. Hokkaido Prefectural Agricultural Experiment Stations and Hokkaido Animal Research Center, Sapporo. (in Japanese)

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Shiga H, Ohyama N, Maeda K, Suzuki M 1985: An evaluation of different organic materials based on their decomposition pattern in paddy soils. Res. Bull. Natl. Agric. Res. Cetr., 5, 1–19. (in Japanese with English summary)

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